Phenology of Bobgunnia madagascariensis (DESV.) J. H. Kirkbr. &amp; Wiersema and Euphorbia sepium N.E. Br. in relation to climatic factors in the Sudano-Guinean zone of Benin

doi:10.21203/rs.3.rs-5154654/v1

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Phenology of Bobgunnia madagascariensis (DESV.) J. H. Kirkbr. & Wiersema and Euphorbia sepium N.E. Br. in relation to climatic factors in the Sudano-Guinean zone of Benin

https://doi.org/10.21203/rs.3.rs-5154654/v1

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Bobgunnia madagascariensis and Euphorbia sepium are two galactogenic species used for livestock farming in Benin. However, there is a few studies on these two species, especially about their characterization and phenology. Knowing plant phenology provides a useful understanding of their autoecology and contributes to conservation and management strategies. The study aimed to describe in relation to climatic factors the different phenological stages of B. madagascariensis and E. sepium in the Sudano-Guinean zone of Benin. Trees spaced at least 13 m apart were chosen randomly and ten individuals of each species were identified and monitored. The observations were made on the phenological stages of both species and were carried out every 10 days during two years in the municipality of Nikki located in Sudano-Guinean zone of Benin. The results shown a single phenological stage (leafing) on E. sepium, characterized by alternating leaf emergence from March to October and leaf fall between November and February. However, three phenological stages were observed (leafing, flowering and fruiting) on B. madagascariensis. Leafing occurred from March to November, flowering from May to August and fruiting from July to February. Peak flowering and fruiting were observed in May-June and August-September, respectively. Leafing of both species was positively and significantly correlated with rainfall. Minimum temperature was positively and significantly correlated (r = 0.61) with flowering on B. madagascariensis. However, fruiting in the same species was negatively correlated (r = -0.89) with maximum temperature. This study provides important information for a better valorization and in situ conservation of the two species in Benin.

Biological sciences/Developmental biology

Biological sciences/Physiology

Biological sciences/Plant sciences

Climatic factors

Conservation

Ecology

Reproductive stage

Vegetative stage

Plant resources exploited by the populations are supposed to be available in large quantities to allow them to achieve their need. However their plant resources are in continuous degradation due to demographic pressure, climate change and strong socio-economic changes characterized by the mechanization of agriculture and overexploitation of forest (Dan et al., 2012 ; Soulama et al., 2015 ; Kouakou et al., 2018). This situation represents a threat to the survival of plant species, particularly those subject to strong anthropogenic pressures. It is necessary to study their phenology to conserve, reproduce and sustain them. Indeed, the phenology of plants (woody or not, domestic or wild) has been the focus of several scientific works (Baker et Reddy, 2001 ; Casero et Galán, 2007 ; Saska et Kuzovkina, 2010 ; Alcaraz et al., 2013 ; Wei et al., 2013). These works, carried out in different ecosystems, helped to improve our knowledge of certain species (vegetation, flowering, fruiting and senescence stages) and to assess the effect of climatic factors on plant phenology. According to Seghieri et al. (2009) and Diallo et al. (2016), plant phenology is the seasonal chronology of periodic phenomena of plant growth and development. It consists of observing the phenological phases or phenophases of plant species (Leafing and leaf fall, flowering and fruiting) (Scheiter and Higgins, 2009). The study of different phenological stages of woody plant species is an important tool for breeders and allows them to have precise data on the phenology of these species. In Benin, some species, especially non-domesticated plants are less studied. Accurate data on the phenology of non-domesticated useful woody species are limited. Most studies to date of important plant species have focused on their ethnobotanical uses (Assogba et al., 2017 ; Adjahossou et al., 2019 ; Lawin et al., 2019). Badou et al. (2017) and Sinasson Sanni et al. (2018) have recently studied the floral and reproductive phenology of Syzygium guineense and the reproductive phenology of Mimusops andongensis and Mimusops kummel respectively. Overall, the level of knowledge of the different phenological stages of the tree species used by local people remains very low in Benin (Adomou et al., 2018). It is probably for this reason that Lawin et al. (2018) felt it necessary to conduct work on the phenological study of Cola millenii (a wild edible fruit tree) for its conservation and domestication. In fact, the knowledge of the phenological characteristics makes it possible to follow the production and to have good seeds in time to better study a plant species, its domestication or its reproduction (Badou et al., 2017 ; Baraka et al., 2018). The study of the phenology of a plant species contributes not only to better describe of the plant but also for better valorization. Studies have shown that the phenological stages of tropical trees are influenced by biotic, climatic and edaphic factors (Forrest et al., 2010 ; Diallo et al., 2016 ; Sinasson Sanni et al., 2018), hence the importance of having detailed data on the phenology of species to enable rational management of plant genetic resources. According to Richardson et al. (2013) and Fétéké et al. (2016), the phenological rhythms of trees are mainly influenced by the intensity of solar radiation and the extent of the dry season. The leaf fall and leafing phases of trees affect photosynthetic activity, which in turn affects primary and secondary growth, survival, and productivity of trees (Kariuki et al., 2006 ; Wagner et al., 2014). Leaf and reproductive phenology are closely linked to local climate variations on an inter and intra-annual scales (Stahle et al., 1999). The main objective of this study was to describe the different phenological stages (phenophases) of Bobgunnia madagascariensis and Euphorbia sepium, two species of galactogenic plants used by livestock farmers and agro-pastoralists in Benin to improve milk production in cows. The specific objectives of the study were to: i) describe Bobgunnia madagascariensis and Euphorbia sepium phenology in Sudano-Guinean zone of Benin, ii) describe and quantify the interannual variation in flowering and fruiting of B. madagascariensis for two consecutive years, iii) test the effect of climatic parameters on the phenology of the two species.

2.1. Study area

The study was conducted in the municipality of Nikki located in the Sudano-Guinean zones of Benin (Fig. 1). This area is located between 7°30’ and 9° 45’N (Gandji et al., 2020; Imorou et al., 2022). The Table 1 summarizes the ecological characteristics of the study area.

Table 1

Climatic characteristics of Sudano-Guinean zones in Benin Republic1
Characteristics	Sudano-Guinean zone
Latitude	8°50′ − 9°10′ N
Longitude	1°55′ − 2°25′ E
Rainfall regime	Unimodal (5–6 months)
Rainy season	April – October
Dry season	November – March
Annual rainfall range (mm)	900–1200
Temperature (°C)	21–40 (mean: 32°C)
Humidity (%)	65
Climate type	Humid tropical
¹Information collected from Gandji et al. (2020) and Ahoyo et al. (2021)

The study area was selected based on the availability of species following the results of a survey carried out in 2019 on galactogenic plant species (Imorou et al., 2021). In fact, Bobgunnia madagascariensis is a species distributed in the Sudano-Guinean zone in Benin (Kirkbride and Wiersema,1997); Euphorbia sepium is a species of the Sahelian zones (Mies et Aschan, 1995).

Figure 1

2.2. Sampling and data collection

The phenological study was conducted in the natural habitat of the species. Phenological surveys were carried out on 10 trees of each species, previously identified based on their health status (green and large leaves, absence of parasites, appropriate age, …) and numbered. The trees were randomly selected at a minimum distance of 13 m from each other (Badou et al., 2017). The surroundings of the trees have been well cleaned (firewalls and fires) to avoid their disturbance by bush fires.

Phenological monitoring of trees was carried out over two years, from October 2019 to September 2021. They were carried out by qualitative observations using the same phenological stages as recommended by Diallo et al. (2016) and Badou et al. (2017): leafing, flowering, and fruiting. Phenological surveys were carried out every month while phenological observations were made every 10 days to identify the duration of each phenological stage. Furthermore, from flower initiation onwards, phenological observations were intensified and carried out every two days until the ripe fruit stage to have an accurate duration of these phenological stages.

Two types of observations (direct and indirect) inspired by the work of Baraka et al. (2018) were performed. Direct observations were made visually on the trees. For indirect observations, the base of the trees was cleaned to observe flowers and fruits as well as dead leaves on the ground. A form was established for the phenological records of each stage, and the following scale was used.

Nothing or no organs characteristic of the stage concerned: 0
Presence of organs characteristic of the stage concerned: 1

During the phenological observations, the start and end dates of each phenological stage were recorded. Climatic data (rainfall, temperature, air and soil moistures) were obtained from the POWER | Data Access Viewer (https://power.larc.nasa.gov/data-access-viewer/).

2.3. Data analysis

The proportion of trees in each phenological stage (leafing, flowering, and fruiting) was calculated per month for each species. Phenological diagrams were made using Minitab 17 software to illustrate the variation of the proportion for each phenological stage over the two years of observation. Spearman correlation coefficient was used to assess the correlation of each phenological stage with the climatic variables. The significance of the correlation coefficient value was tested in the 'Hmisc' package (Lawin et al., 2021) of the R software version 3.6.3 (2020-02-29). The paired Student's t-test was used to examine the variation in the duration of the productive stages (flowering and fruiting) of B. madagascariensis according to the collection periods (October 2019 to September 2020 and October 2020 to September 2021). Statistical analyses were performed with R software version 3.6.3 (2020-02-29).

3.1. Rainfall, temperature and humidity in the Sudano-Guinean zone during the two years of the study

The rainfall was spread over a period of eight months in both the first and second years of observations, but with a difference in the quantities of rainfall. Total rainfall was 1212.89 mm in the first year (October 2019 to September 2020) and 1526.17 mm in the second year (October 2020 to September 2021). July, September, and October were the wettest months in the first year, while June, July and August were the wettest months in the second year (Fig. 2a). Rainfall was irregularly distributed. The average rainfall for the two study years was 1369.50 mm.

The maximum temperatures were observed during the months of March, April and May in both years of the study (Fig. 2b). Indeed, during the first year of observation as well as during the second year of observation, the recorded climatic conditions (rainfall and temperature) seem to be quite favourable for plant development. Relative humidity followed the same trend during the two years of the study. The lowest humidity values were recorded in February and the highest values between July and October (Fig. 2c).

Figure 2

3.2. Phenological stages of Bobgunnia madagascariensis

The leaf production phase took place each year during nine months from March to November (Fig. 3). This phase of leafing began in March with the first rains and extends until November, a dry month without rain and therefore little water availability (Fig. 3a). Full leafing (production phase) took place between April and November. However, some trees still had leaves in December. The trees lost their leaves between December to February corresponding to the leaf fall phase (Fig. 3). This period corresponds to the dry period of the year characterized by a cessation of the rains and a cool dry wind (drop in temperature) accelerating the drying of the leaves of the trees. The numbered and monitored trees completely lost their leaves in January and February of each year during the two years of study.

Flowering started in May and lasted until September, corresponding to a duration of four months (Fig. 3). Flowering took place only during the rainy season, when the average temperature was between 25 and 28.5°C. The highest proportions of flowering trees were observed in May-June in the first year and in June in the second year.

The fruiting stage was observed from July to January in the first year (seven months) and from July to February in the second year (eight months) (Fig. 3c and d). This stage started in the rainy season and continued into the dry season to produce ripe fruit (July to February). The temperature during fruiting varied between 21.9 and 26.6°C with an average temperature of 24.6°C (Fig. 3b). Trees of B. madagascariensis were therefore fruiting during the low temperature period in both years.

The results of this study also revealed a low fruiting rate of B. madagascariensis trees. In year 1, only 50% of the monitored trees fruited and 60% in year 2. From October of each observation period, a decrease in the proportion of fruiting trees was observed (Fig. 3c and d). Peak fruiting was observed in August and September in both the first and second years of observation. The minimum proportion of fruiting trees was observed in February in both years of observation.

Figure 3

3.3. Interannual variation in flowering and fruiting of B. madagascariensis for two consecutive years

In year 1, flowering lasted 80.3 ± 21.5 days (about 2 months and 20 days), compared to 89.2 ± 31.5 days (about 3 months) in year 2 (Table 2). Fruiting lasted approximately 4 months 12 days (132.0 ± 69.1 days) in year 1 compared to 4 months 20 days (140.0 ± 64.9 days) in year 2. The average flowering and fruiting times were 84.75 ± 26.5 days and 136 ± 67.0 days respectively. There was not a significant difference between years in the duration of flowering (p = 0.310 > 0.05) (Table 2). There was also no significant difference in fruiting between the years (p = 0.762 > 0.05) (Table 2).

Table 2

Interannual variation in the duration of reproductive stages
Phenophase	Duration (days)		mean ± SE	t-value	P
Phenophase	Year 1	Year 2	mean ± SE	t-value	P
Flowering	80.3 ± 21.5	89.2 ± 31.5	84.75 ± 26.5	-1.129	0.310^ns
Fruiting	132.0 ± 69.1	140.0 ± 64.9	136.0 ± 67.0	-0.324	0.762^ns
ns: test not significant at the 5% level according to Student's t test.

3.4. Phenological stage of Euphorbia sepium

During the two years of observation, only the leafing stage was observed in E. sepium. This stage was characterized by a leaf production phase that took place during eight months from March to October of each year (Fig. 4c and d). The leaf production phase started in March with the first rains and lasted until October, the beginning of the dry period of the year. However, some shrubs (about 2/10) continued to bear leaves in November. Full leafing (leaf production) occurs between May and October. Total leaf loss by the shrubs was observed between December and February (Fig. 4c and d) which corresponds to the dry and cold period of the year in the study area (Fig. 4a and b). In contrast, during the two years of observations, none of the ten (10) monitored E. sepium shrubs flowered or produced fruit.

Figure 4

3.5 Effect of climatic parameters and soil moisture on the phenology of B. madagascariensis and E. sepium

Significant positive or negative correlations were observed between climatic variables, soil moisture and phenological stages of the two species (Figs. 5 and 6).

Indeed, on B. madagascariensis, the results showed that the average rainfall (r = 0.71; p = 0.010; Fig. 5a), the average relative humidity (r = 0.90; p = 0.000; Fig. 5d) and the minimum temperature average (r = 0.79; p = 0.002; Fig. 5g) were positively and significantly correlated with leafing. The results also showed a positive and significant correlation between minimum temperature and flowering (r = 0.61; p = 0.035; Fig. 5h). However, a negative and significant correlation (r = -0.89; p = 0.000) was observed between maximum temperature and fruiting (Fig. 5l).

Only phenological stage observed on E. sepium shrubs was leafing. Spearman's correlation test revealed that the average rainfall (r = 0.87; p = 0.000; Fig. 6a), the average minimum temperature (r = 0.89; p = 0.000; Fig. 6b), and the average relative humidity (r = 0.89; p = 0.000; Fig. 6d) were positively and significantly correlated with the leafing.

concerning the influence of soil moisture on the phenological stages of the two species studied, the results highlighted a significant correlation. Indeed, soil moisture at 5 cm was positively and significantly correlated with leafing (r = 0.74; p = 0.006; Fig. 5m) and fruiting (r = 0.73; p = 0.006; Fig. 5o) of B. madagascariensis. The same results were obtained with soil moisture in the root zone for leafing and fruiting of this species. Also, on E. sepium a positive and significant correlation was observed between soil moisture at 5 cm and leafing, then between soil moisture at root level and leafing (Fig. 6e and f).

Figure 5

Figure 6

4.1. Phenology of Bobgunnia madagascariensis and Euphorbia sepium

The study aimed to characterize the phenology of B. madagascariensis and E. sepium in the Sudano-Guinean zone of Benin. The results showed that B. madagascariensis trees bore leaves from March to November, i.e. for nine months, and E. sepium shrubs from March to October, i.e. for eight months of the year. These results were slightly different from those obtained by other authors in different tropical species. In South Africa, Venter et Witkowski (2019) found that Adansonia digitata trees bear leaves for six months of the year. In Benin, Lawin et al. (2021) reported that Cola millenii K.Schum., carries the leaves throughout the year. The observed difference in the duration of the leafing stage of these species could be related to the genetic characteristics of each species but also to the environment since the studies were conducted in different environments. This idea is reinforced by the work of Azalou-Tingbe et al. (2022) in Benin, which showed that the phenophases of Garcinia kola vary according to phytogeographical districts. Also, the influence of rainfall and temperature on Prunus avium leafing in Tunisia had been reported by Jdaidi et Hasnaoui (2016). Furthermore, in both species studied, leafing stage (leaf emergence) started in March, the month in which the first rains were recorded in the study area during the two years of tree monitoring and data collection. This would explain the leaves emergence and thus the beginning of leafing stage in B. Madagascariensis and E. sepium. Our results are different from those obtained by Azalou-Tingbe et al. (2022) on Garcinia kola Heckel in the Guineo-Congolese zone of Benin. These authors reported that leafing takes place globally from August to December and then from January to March. Comparing to our results, the different could be related to the difference of climatic zones (Adomou et al., 2006), Guineo-Congolese zone in these case against Sudano-Guinean zone of our study area.

Trees of both species lost almost all their leaves between January and February for B. madagascariensis and between December and February for E. sepium. This result, which provides information on the periods of leaflessness, particularly on E. sepium, is very important for the valorization of this species. In fact, the organ of E. sepium that is used in galactogenic preparations by the populations is the leaf. It is therefore important to know at what time of year this organ is available to plan its harvesting and operations allowing its conservation over a long period.

The results also showed the total absence of flowering and fruiting in E. sepium despite they got the fruiting age. Indeed, during the two years of observation, any flower buds, flowers, or fruits on the monitored shrubs were not observed. This result is opposed to those of Riina (2020) and Riina et al. (2021) who observed flowers and fruits in E. sepium. This is because the shrubs monitored for this study are subject to human pressure characterized by leaf removal and severe pruning (abusive cutting) of branches, which could affect their productive phenology (flowering and fruiting). For example, in Burkina Faso, Nacoulma et al. (2017) found that A. africana trees subjected to very severe bark and leaf harvesting intensity did not produce fruit. Similarly, Gaoue and Ticktin (2008) reported that pruning significantly reduced fruit production of Khaya senegalensis, in the Sudanese region of Benin.

B. madagascariensis flowered in May, June, July, August and September and fruited from July to February. Thus, the entire flowering stage of the species takes place in the rainy season. The fruiting stage begins in the rainy season and lasts until the dry season. Similar results were obtained by Lomalisa et al. (2021) in Guarea cedrata (A.Chev.) Pellegr. and Guarea thompsonii Sprague & Hutch. (Meliaceae) in the Democratic Republic of Congo. Diatta et al. (2022) had also obtained similar results in 18 populations of Acacia senegal (L.) Wild., from the distribution area of this species in Africa and Asia. Our results are contrary to those obtained by Sinasson Sanni et al. (2018) in Mimusops andongensis and Mimusops kummel Bruce ex A.DC. in Benin and Jaouadi et al. (2012) in Tunisia on Acacia tortilis subsp. The first authors found that flowering in the species studied starts in the dry season and ends in the rainy season, whereas fruiting took place in the rainy season. The second authors found that the flowering and fruiting phases of this species (Acacia tortilis subsp.) occurred in the dry period. These differences could be due to abiotic factors in the different study environments and/or the genetic characteristics of the species studied.

Within the two species (B. madagascariensis and E. sepium) studied, the trees monitored did not begin their phenophases (leafing, flowering and fruiting) at the same time. These results are similar to those of Lawin et al. (2021) who also reported that monitored C. millenii plants did not start flowering and fruiting at the same time. This would be an expression of genetic variability of the monitored tree individuals. Satake et al. (2022) reported that phenological traits in plant species, namely growth, flowering and fruiting are determined by genotype and environment.

B. madagascariensis and E. sepium showed differences in their phenological stages. For B. madagascariensis, leafing, flowering and fruiting were observed while only leafing was observed on E. sepium. In fact, B. madagascariensis is a species that can reproduce both asexually (Berger and Schaffner, 1995 ; Amri, 2012) and sexually (Thokozani et al., 2011). The second mode of reproduction of the species (sexual reproduction) justifies that it carries out the reproductive phenological stages which include flowering and fruiting, fundamental to produce seeds. In contrast, E. sepium is vegetatively propagated from cuttings (Riina, 2020 ; Biaou et al., 2022). This rarity of the generative phase could be due to the polyploidy that characterizes many vegetatively propagated plants.

4.2. Climatic parameters and phenological behaviour of Bobgunnia madagascariensis and Euphorbia sepium

The phenology of B. madagascariensis as well as that of E. sepium is dependent on climatic parameters and soil moisture. Indeed, the results of the study showed that rainfall, minimum temperature, and relative humidity are positively correlated with the leafing of the two species.

Thus, the emergence and production of leaves in trees are linked to the increase in precipitation combined with the drop in temperature and the increase in the relative humidity of the air. Mahaman et al. (2007) obtained in their study on the phenology of 28 ligneous species of the "W" National Park of Niger, that the phase of leafing is under the close dependence of the climatic conditions, of the humidity of the air especially in zone tropical. Also, Jdaidi and Hasnaoui (2016) indicated that the increase in precipitation was favorable to leafing of Prunus avium. These results not only allow to know the periods of availability of leaves in B. madagascariensis and E. sepium in the Sudano-Guinean zone of Benin but also to predict, in a context of climate change, the duration and intensity of the leafing stage. of both species. In fact, the possible reduction in the duration of the rainy season combined with the rise in temperature would reduce the duration of leafing.

Flowering and fruiting of B. madagascariensis are influenced by temperature. This study showed a positive and significant correlation between minimum temperature and flowering in B. madagascariensis. The low temperatures are favorable to the flowering of the species. Fruiting is negatively correlated with maximum temperature. High temperatures are unfavorable to the production of fruits in the species and a continuous rise in temperature during the fruiting period would compromise its regeneration since one of the ways of propagation of the species is sexual reproduction (Thokozani et al., 2011). Lawin et al. (2021) and Ávila et al. (2022) reported that flowering and fruiting of C. millenii and flowering of Mauritiella armata were positively correlated with maximum temperature. Sène et al. (2020) reported also that increased temperature and humidity induced flowering of Sclerocarya birrea (A. Rich.) Hochst. These results are contrary to ours which showed a negative effect of high temperatures on the fruiting of B. madagascariensis. The results of the study then indicate that temperature, as well as the physiology of plant species, are important indicators to be considered in models for predicting reproductive phenology (flowering and fruiting) and therefore the production of B. madagascariensis. Barrett et Brown (2021) had mentioned that temperature was the factor most affecting flowering and fruit and pod production of several species (Dichrostachys cinerea L.) Wight & Arn., Senegalia burkei (Benth.) Kyal. & Boatwr., Vachellia robusta subsp. Robusta) of the botanical family Fabaceae or Leguminosae like B. madagascariensis.

Although rainfall is considered as the main factor regulating plant phenology in the dry tropics, the results of this study did not show a significant correlation between rainfall and reproductive phenology (flowering and fruiting) of B. madagascariensis. This suggests that the numbers of flowers and fruits produced do not necessarily increase with increasing precipitation. Our results are similar to those of Bao et al. (2022), obtained in the desert species Nitraria tangutorum concerning its fruiting. Polansky et Boesch (2013) obtained in Ivory Coast, significant and negative correlations between precipitation and the total proportion of individuals showing fruits in 39 of the 44 species studied, also suggesting that the variability of fruit abundance was not associated with precipitation. Similar observations were made by Seghieri et al. (2009) in several tropical species including P. biglobosa, Pericopsis laxiflora (Benth.) Harms, Isoberlinia doka Craib & Stapf and Isoberlinia tomentuosa (Harms) Craib & Stapf. However, Lima et al. (2021) reported contrary results on different tropical species (Bauhinia cheilantha (Bong.) Steud., Piptadenia stipulacea (Benth.) Ducke), demonstrating that precipitation was the climatic factor most likely to affect flowering and fruiting tropical woody species.

Soil humidity at 5 cm and at the root level significantly influenced the leafing of E. sepium and the leafing and fruiting stages of B. madagascariensis. However, the flowering of the latter remains unaffected by soil humidity at 5 cm and humidity at the root level. These results, which give more information about these two species, the phenological stages most sensitive to a lack of water in the soil, provide guidance on the measures to be taken in dry conditions. The effects of soil moisture on plant phenology were also reported by Luo et al. (2021) who indicated that soil moisture is a determining factor in plant growth.

4.3. Implications for development

The continuous harvesting of organs of Bobgunnia madagascariensis and Euphorbia sepium, whose phenology and propagation techniques remain poorly known and poorly controlled respectively, constitutes a major threat to national biodiversity. This study has deepened and provided more detailed knowledge on the phenology and diversity of these two species, which are two of the most promising galactogenic plant species for improving milk production in cows in Benin (Imorou et al., 2021 ; Agani et al., 2022 ; Atchouké et al., 2022). Indeed, the study on phenology made it possible to identify the phenological stages of these two species, knowledge that is essential for their better use and conservation. The results thus obtained provide guidance to breeders, agro-pastorals and promoters of livestock farms on the precise periods of availability and therefore of collection of the organs of these species, particularly the leaves of E. sepium used in galactogenic recipes. They also provide information on the period of availability of the fruits of B. madagascariensis which represent seeds for domestication and the establishment of a garden of galactogenic plants for exploitation and improvement of milk production in cows.

This study provides useful information on the phenology of B. madagascariensis and E. sepium. The study revealed that E. sepium has only the leafing stage, important information for domestication and propagation studies. The results showed that B. madagascariensis bears leaves for nine months and E. sepium for eight months of the year. This information is essential for users of the leaves of both species in various galactogenic and medicinal recipes who now know the period and duration of availability of this organ in the year. Concerning B. madagascariensis, flowering takes place from May to September and fruiting from July to February. These results, which provide information on the periods of availability of the fruits and therefore of the seeds of this species, which is useful for the domestication and conservation programs in situ and ex situ of the species. The study showed that climatic factors significantly influence the phenological stages of the two species studied. Taking these results into account will be of great importance in predicting the regeneration of B. madagascariensis and the phenological patterns of both species. The same observations could be made in the Sudanian zone to analyze the phenological behaviour of the two species in this climatic zone and to evaluate the effect of the climatic zone on their phenological stages to identify the periods of availability of organs (leaves, fruits) of importance for a better valorisation and a sustainable management of the two species. Morphological and molecular characterization studies will be needed to understand the variability within these two species to initiate strategies for their sustainable management.

CRediT authorship contribution statement

Lucien Imorou conceived the work with advice from Lucrain Cakpo and Léonard E. Ahoton. Lucien Imorou and Lucrain Cakpo collected the data. Lucien Imorou processed the data and performed the statistical analyses with a significant contribution of Dayou Ephreme Dossavi. Lucien Imorou drafted the manuscript with significant contribution of Dayou Ephreme Dossavi, Daouda O. Bello, Hubert Adoukonou-Sagbadja, Adam Ahantchédé and Léonard E. Ahoton. Léonard E. Ahoton and Hubert Adoukonou-Sagbadja supervised the work. All authors read and approved of the final manuscript.

Conflict of Interest

All authors declare that they do not have any conflict of interest.

Funding

This work was supported by the University of Abomey-Calavi (UAC), Benin Republic, through the Research Competitive Funds allocated to the PROLAIT project Number 626–2018/UAC/SG/SAF/VR-RU/ SPRSP/SA. The funder did not play a rule in the research design data collection and paper written.

Author Contribution

Acknowledgement

The authors acknowledge the Ministry of Higher Education of Benin and the University of Abomey-Calavi for the financial support through the Research Competitive Funds allocated to the PROLAIT project. The authors also extend their special thanks to all the fellow doctoral students who have contributed to this work. We are also grateful to the anonymous reviewers for their constructive comments on this work.

Data Availability

The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.

Adjahossou SGC, Houéhanou DT, Toyi M, Salako VK, Ahoyo CC, Lesse P, Tente B, Houinato MRB (2019) Dépendance socioculturelle des connaissances locales des usages de Isoberlinia spp. au Moyen-Bénin, Afrique de l’Ouest. Bois For Trop 339: 33–43. https://doi.org/10.19182/bft2019.339.a31702
Adomou AC, Sinsin B, der Maesen V, Gerardus LJ (2006) Phytosociological and chorological approaches to phytogeography: a meso-scale study in Benin. Syst Geogr Plants 76:155–178.
Adomou CA, Dassou GH, Yedomonhan H, Favi GA, Ouachinou J, Aboudjan M, Houenon GAH (2018) Analyse des connaissances traditionnelles et des déterminants relatifs à l’utilisation de Newbouldia laevis (P. Beauv.) Seemann ex Bureau (Bignoniaceae) au Sud-Bénin. Afr Sci 14(1): 194–205.
Agani Z, Cyrille BK, Guénole AC, Habirou SI, Bello O, Daouda HM, Dossou J, Babatoundé S (2021) Préparations galactogènes utilisées par les agroéleveurs au Bénin: espèces végétales, proportions d’organes impliqués et production laitière chez les vaches Borgou. J Appl Biosci 157 : 16161–16171. https://doi.org/10.35759/JABs.157.2
Ahoyo CC, Houehanou TD, Yaoitcha AS, Prinz K, Kakai RG, Sinsin BA, Houinato MR (2021) Traditional medicinal knowledge of woody species across climatic zones in Benin (West Africa). J Ethnopharmacol 265: 113417. https://doi.org/10.1016/j.jep.2020.113417
Alcaraz ML, Thorp TG, Hormaza JI (2013) Phenological growth stages of avocado (Persea americana) according to the BBCH scale. Sci Hortic 164: 434–439. https://doi.org/10.1016/j.scienta.2013.09.051
Amri E (2012) The effect of auxins (IBA, NAA) on vegetative propagation of medicinal plant Bobgunnia madagascariensis (Desv.) JH Kirkbr & Wiersema. TaJONAS Tanzan. J Nat Appl Sci 2: 359–366.
Assogba GA, Fandohan AB, Salako VK, Assogbadjo AE (2017) Usages de Bombax costatum (Malvaceae) dans les terroirs riverains de la Réserve de biosphère de la Pendjari, République du Bénin. Bois For Trop 333: 17–29. https://doi.org/10.19182/bft2017.333.a31465
Ávila MAD, Azevedo IFPD, Antunes JR, Souza CRD, dos Santos RM, Fonseca RS, Nunes YRF (2022) Temperature as the main factor affecting the reproductive phenology of the dioecious palm Mauritiella armata (Arecaceae). Acta Bot Bras 36: e2021abb0111. doi: 10.1590/0102-33062021abb0111
Azalou-Tingbe CN, Assogbadjo AE, Ahanhanzo C, Idohou R, Cacaï GTH, Akin YY (2022) Phénophases de Garcinia kola au Bénin: Influence du phytodistrict et de l’âge des sujets. Rev. Marocaine Sci Agron Vét 10(1): 185-194
Badou RB, Yedomonhan H, Adomou AC, Akoegninou A (2017) Phénologie florale et production fruitière de Syzygium guineense (Willd.) DC. subsp. macrocarpum (Myrtaceae) en zone soudano-guinéenne au Bénin. Int J Biol Chem Sci 11(5): 2466–2480.
Baker JT, Reddy VR (2001) Temperature effects on phenological development and yield of muskmelon. Ann Bot 87: 605–613.
Bao F, Xin Z, Liu M, Li J, Gao Y, Lu Q, Wu B (2022) Preceding Phenological Events Rather than Climate Drive the Variations in Fruiting Phenology in the Desert Shrub Nitraria tangutorum. Plants 11: 1578.
Baraka LP, Semeki NJ, Maloti JM, Kadiata BD (2018) Observations préliminaires de la phénologie des Annonaceae, Fabaceae, Myristicaceae et Rubiaceae dans la Réserve de Biosphère de Luki, en République Démocratique du Congo. Int J Innov Appl Stud 23(4): 465–473.
Barrett A, Brown L (2021) Effects of rainfall, temperature and photoperiod on the phenology of ephemeral resources for selected bushveld woody plant species in southern Africa. Plos One 16: e0251421. https://doi.org/10.1371/journal.pone.0251421
Berger K, Schaffner W (1995) In vitro propagation of the leguminous tree Swartzia madagascariensis. Plant Cell Tissue Organ Cult 40: 289–291.
Biaou ODB, Balogoun I, Bello OD, Chabi F, Saïdou A, Ahoton EL (2022) Propagation by stem cutting of Euphorbia balsamifera (Aiton), a galactogenic plant in Benin. J Appl Biosci 172: 17894–17904. https://doi.org/10.35759/JABs.172.4
Casero MTG, Galán C (2007) Flowering phenology of Mediterranean" Quercus" species in different locations (Córdoba, SW Iberian Peninsula). Acta Bot Malacit 127–146.
Dan CB, Sinsin BA, Mensah GA, Lejoly J (2012) Influence des activités anthropiques sur la diversité floristique des communautés végétales de la forêt marécageuse de Lokoli au Sud-Bénin. Int J Biol Chem Sci 6(6): 3064–3081.
Diallo MD, Mahamat-Saleh M, Diallo A, Bassene C, Ndiaye O, Niang K, Aliou D, Guisse A (2016) Caractérisation de la variabilité des phénophases de cinq espèces végétales sahéliennes dans la zone nord Ferlo, Sénégal. Rev Ivoir Sci Technol 27: 117–135.
Diatta O, Diallo AM, Sanogo D, Nielsen LR, Ræbild A, Kjær ED, Hansen JK (2022) Variation in phenology of Acacia senegal (L.) Wild. in relation to origin and ploidy level: Implications for climatic adaptation. Glob Ecol Conserv 33: e01957. https://doi.org/10.1016/j.gecco.2021.e01957
Fétéké F, Fayolle A, Dainou K, Bourland N, Dié A, Lejeune P, Doucet J-L, Beeckman H (2016) Variations saisonnières de la croissance diamétrique et des phénologies foliaire et reproductive de trois espèces ligneuses commerciales d’Afrique centrale. Bois For Trop 330: 3–21.
Forrest J, Inouye DW, Thomson JD (2010) Flowering phenology in subalpine meadows: Does climate variation influence community co-flowering patterns? Ecology 91: 431–440.
Gandji K, Tovissodé FC, Azihou AF, Akpona JDT, Assogbadjo AE, Kakaï RLG (2020) Morphological diversity of the agroforestry species Moringa oleifera Lam. as related to ecological conditions and farmers’ management practices in Benin (West Africa). South Afr J Bot 129: 412–422. https://doi.org/10.1016/j.sajb.2019.10.004
Gaoue OG, Ticktin T (2008) Impacts of bark and foliage harvest on Khaya senegalensis (Meliaceae) reproductive performance in Benin. J Appl Ecol 45: 34–40.
Imorou L, Fassinou Hotegni NV, Togbe EC, Goudou HG, Achigan-dako EG, Adoukonou-Sagbadja H, Ahoton LE (2022) Morphological diversity of Bobgunnia madagascariensis (Desv.) J. H. Kirkbr. & Wiersema, across the Sudanian and Sudano-Guinean zones of Benin Republic. South Afr J Bot 147: 731–740. https://doi.org/10.1016/j.sajb.2022.03.013
Imorou L, Togbé EC, Fassinou Hotegni NV, Bello DO, Biaou BO, Nuer AT, Adoukonou-Sagbadja H, Ahoton LE (2021) Galactogenic plant diversity, phenology and local in situ conservation practices in agro-ecological zones of Benin Republic. Genet Resour Crop Evol 68: 979–998. https://doi.org/10.1007/s10722-020-01039-7
Jaouadi W, Hamrouni L, Khouja ML (2012) Phénologie d’Acacia tortilis subsp. addiana dans le parc national de Bou Hedma en Tunisie, effet du site sur les phénophases de l’espèce. Bois For Trop 312: 21–29.
Jdaidi N, Hasnaoui B (2016) Influence des facteurs climatiques sur la phénologie de Merisier (Prunus avium) au Nord-Ouest de la Tunisie. Rev Marocaine Sci Agron Vét 4: 23–31.
Kariuki M, Rolfe M, Smith RGB, Vanclay JK, Kooyman RM (2006) Diameter growth performance varies with species functional-group and habitat characteristics in subtropical rainforests. For Ecol Manag 225: 1–14. https://doi.org/10.1016/j.foreco.2005.07.016
Kirkbride JH, Wiersema JH (1997) Bobgunnia, a new African genus of tribe Swartzieae (Fabaceae, Faboideae). Brittonia 49: 1–23.
Kouakou ATM, Assale AAY, Barima YSS (2018) Impact des pressions anthropiques sur la flore de la forêt classée du Haut-Sassandra (Centre-ouest de la Côte d’Ivoire). Tropicultura 36(2): 155-170.
Lawin IF, Fandohan AB, Gandji K, Assogbadjo AE, Ouinsavi CAIN (2018) Cola millenii K. Schum: Etat des connaissances et perspectives de recherche. Int J Biol Chem Sci 12(3): 1494–1515.
Lawin IF, Houètchégnon T, Fandohan AB, Salako VK, Assogbadjo AE, Ouinsavi CAIN (2019) Connaissances et usages de Cola millenii K. Schum.(Malvaceae) en zones guinéenne et soudano-guinéenne au Bénin. Bois For Trop 339: 61–74. https://doi.org/10.19182/bft2019.339.a31716
Lawin IF, Salako KV, Fandohan AB, Assogbadjo AE, Ouinsavi CAIN (2021) Phénologie de Cola millenii K.Schum. au Bénin. Biotechnol. Agron Soc Env 25(3): 161-171
Lima DF, Mello JH, Lopes IT, Forzza RC, Goldenberg R, Freitas L (2021) Phenological responses to climate change based on a hundred years of herbarium collections of tropical Melastomataceae. PloS One 16: e0251360. https://doi.org/10.1371/journal.pone.0251360
Lomalisa RK, Mokoso JDDM, Sefu JA, Malale HNSW (2021) Phenological studies and fruit scattering of Guarea cedrata and Guarea thompsonii (Melaiceae) in the semi-deciduous Forestry Massive of Kisangani (Democratic Republic of Congo). Geo-Eco-Trop 45: 145–159.
Luo M, Meng F, Sa C, Duan Y, Bao Y, Liu T, De Maeyer P (2021) Response of vegetation phenology to soil moisture dynamics in the Mongolian Plateau. Catena 206: 105505. https://doi.org/10.1016/j.catena.2021.105505
Mahamane A, Mahamane S, Lejoly J (2007) Phénologie de quelques espèces ligneuses du parc national du «W» du Niger. Sécheresse, 18(4): 1-13.
Mies BA, Aschan G (1995) Radiation regime and temperature condition in the canopy of the succulent shrub Euphorbia balsamifera. Vieraea 24: 15–125.
Nacoulma BMI, Lykke AM, Traoré S, Sinsin B, Thiombiano A (2017) Impact of bark and foliage harvesting on fruit production of the multipurpose tree Afzelia africana in Burkina Faso (West Africa). Agrofor Syst 91: 565–576. https://doi.org/10.1007/s10457-016-9960-9.
Polansky L, Boesch C (2013) Long-term changes in fruit phenology in a West African lowland tropical rain forest are not explained by rainfall. Biotropica 45: 434–440.
R Core Team (2020) R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. URL https://www.R-project.org/
Richardson AD, Keenan TF, Migliavacca M, Ryu Y, Sonnentag O, Toomey M (2013) Climate change, phenology, and phenological control of vegetation feedbacks to the climate system. Agric For Meteorol 169: 156–173.
Riina R (2020) Three sweet tabaibas instead of one: splitting former Euphorbia balsamifera sl and resurrecting the forgotten Euphorbia sepium. World 16(2): 41-45
Riina R, Villaverde T, Rincón-Barrado M, Molero J, Sanmartín I (2021) More than one sweet tabaiba: Disentangling the systematics of the succulent dendroid shrub Euphorbia balsamifera. J Syst Evol 59: 490–503.
Salifou CFA, Kassa KS, Ahounou SG, Moussa H, Dotché IO, Agbozo JM, Issifou MT, Youssao IAK (2017) Plantes lactogènes des bovins et leurs modes de préparation dans les élevages traditionnels au Bénin. Livest Res Rural Dev 29: 29.
Saska MM, Kuzovkina YA (2010). Phenological stages of willow (Salix). Ann Appl Biol 156: 431–437.
Satake A, Nagahama A, Sasaki E (2022) A cross-scale approach to unravel the molecular basis of plant phenology in temperate and tropical climates. New Phytol 233: 2340–2353.
Scheiter S, Higgins SI (2009) Impacts of climate change on the vegetation of Africa: an adaptive dynamic vegetation modelling approach. Glob Change Biol 15: 2224–2246.
Seghieri J, Vescovo A, Padel K, Soubie R, Arjounin M, Boulain N, de Rosnay P, Galle S, Gosset M, Mouctar AH (2009) Relationships between climate, soil moisture and phenology of the woody cover in two sites located along the West African latitudinal gradient. J Hydrol 375: 78–89. https://doi.org/10.1016/j.jhydrol.2009.01.023
Sène AL, Diallo A, Diallo MD, Sagna MB, Ndiaye O, Guisse A (2020) Influence of temperature and rainfall on the phenology of Sclerocarya birrea (A. Rich) Hoscht in the Ferlo Zone (Senegal). Am J Agric For 8: 181–189.
Sinasson Sanni GK, Shackleton CM, Sinsin B (2018) Reproductive phenology of two Mimusops species in relation to climate, tree diameter and canopy position in Benin (West Africa). Afr J Ecol 56(2): 323–333.
Soulama S, Kadeba A, Nacoulma BM, Traoré S, Bachmann Y, Thiombiano A (2015) Impact des activités anthropiques sur la dynamique de la végétation de la réserve partielle de faune de Pama et de ses périphéries (sud-est du Burkina Faso) dans un contexte de variabilité climatique. J Appl Biosci 87: 8047–8064.
Stahle DW, Mushove PT, Cleaveland MK, Roig F, Haynes GA (1999) Management implications of annual growth rings in Pterocarpus angolensis from Zimbabwe. For Ecol Manag 124: 217–229.
Thokozani BL, Zulu D, Sileshi CW, Teklehaimanot Z, Gondwe DS, Sarasan V, Stevenson P (2011) Seed germination and in vitro regeneration of the African medicinal and pesticidal plant, Bobgunnia madagascariensis. Afr J Biotechnol 10: 5959–5966.
Venter SM, Witkowski ET (2019) Phenology, flowering and fruit-set patterns of baobabs, Adansonia digitata, in southern Africa. For Ecol Manag 453: 117593.
Wagner F, Rossi V, Aubry-Kientz M, Bonal D, Dalitz H, Gliniars R, Stahl C, Trabucco A, Herault B (2014) Pan-tropical analysis of climate effects on seasonal tree growth. PLoS One 9: e92337. https://doi.org/10.1371/journal.pone.0092337
Wei YZ, Zhang HN, Li WC, Xie JH, Wang YC, Liu LQ, Shi SY (2013) Phenological growth stages of lychee (Litchi chinensis Sonn.) using the extended BBCH-scale. Sci Hortic 161: 273–277.

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Phenology of Bobgunnia madagascariensis (DESV.) J. H. Kirkbr. & Wiersema and Euphorbia sepium N.E. Br. in relation to climatic factors in the Sudano-Guinean zone of Benin

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