Epimedium sagittatum (Sieb. et Zucc.) Maxim. (also known as “three branches and nine leaves grass”) is one of the most important traditional medicinal plants in China. It belongs to Epimedium, a perennial herbaceous plant in the Berberidaceae family (Wen et al.,2022). First recorded in Shennong's Classic of Materia Medica, it was listed as a top grade herb (Xu et al.,2020) with the effects of reinforcing kidney yang, strengthening muscles and bones, dispelling rheumatism, etc. It is often used to treat kidney yang deficiency, osteoporosis and other diseases (Wei et al.,2023; Wang et al.,2023). With the continuous in-depth research on Epimedium in modern science, the latest research has found that it also has anti-tumor effects, especially on patients with advanced liver cancer (Li et al.,2021). This has led to an increasing demand for Epimedium, and wild resources cannot meet the demand, resulting in rising prices. In order to obtain a large amount of Epimedium, artificial cultivation has begun. Currently, Epimedium seeds are expensive. In the cultivation process, it was discovered that although Epimedium sagittatum has abundant flowering, its reproductive ability is low, the seed setting rate is low, and the germination rate is extremely low. Therefore, there are few seedlings in natural populations (Cui et al.,2022).
It can be seen from the above that the weak reproductive ability and low seed germination rate of Epimedium sagittatum have always been a problem in Epimedium cultivation. Studies have found that the size of pollen viability directly affects the pollination and fertilization processes of plants, which is closely related to the yield and quality of plant seeds (Bai et al.,2023). Testing the viability of Epimedium sagittatum pollen at different flowering stages before pollination can understand the viability, development and physiological characteristics of Epimedium sagittatum pollen, and grasp the morphology of sterile pollen, providing a theoretical basis for artificial breeding (Li et al.,2023; Xu et al.,2012). Therefore, researching the viability and germination characteristics of Epimedium sagittatum pollen is very necessary to improve pollination breeding efficiency and reasonably carry out breeding to increase seed germination rate and obtain high-quality Epimedium sagittatum seeds. On this basis, it is of great value and significance to establish scientific and effective pollination methods for the future, accelerate the breeding process of excellent Epimedium sagittatum varieties, shorten the differentiation period between varieties, and thus enhance the competitiveness of Epimedium sagittatum germplasm. At the same time, it can provide a basis for the construction of the Epimedium sagittatum breeding system under artificial cultivation conditions and production application, thereby promoting the realization of maximized economic benefits in the large-scale production of Epimedium sagittatum. However, research and reports on pollen viability detection of this species have not been seen so far.
This paper systematically studies the flowering dynamics and floral characteristics of Epimedium sagittatum. It also determines the pollen viability at different developmental stages and screens suitable methods for rapid detection of pollen viability in Epimedium sagittatum. The aim is to deeply understand its flowering habits and reproductive characteristics, enrich data on flower development and reproductive regulation of Epimedium sagittatum, explore the limiting factors affecting its breeding process, discuss its breeding habits and pollination methods, and explore ways to improve the pollen viability of Epimedium sagittatum. This study aims to reveal the flowering mechanism of Epimedium sagittatum, clearly understand the physiological and biochemical characteristics of its pollen at different developmental stages, grasp the changes in pollen viability, thereby determine the optimal pollination time and pollen testing method. The purpose is to provide preliminary research basis for exploring artificial assisted fertilization technology, improving seed viability, guiding artificial cultivation management for high yield and efficiency, simplifying production procedures, and selecting new varieties in the future. This will provide preliminary research basis for renewing and reproductive biological studies as well as selecting new varieties of this species.