竹叶眼子菜种子的萌发实验研究

Seed Germination of Potamogeton malaianus

竹叶眼子菜(Potamogetonmalaianus)是长江中下游湖泊沉水植被中的优势种,在野外条件下主要依靠断枝繁殖,很少发现它的实生苗。在实验条件下对竹叶眼子菜进行了种子萌发研究,探讨了萌发基质、温度和光暗周期以及冷藏时间对种子萌发的影响。结果表明,干藏3个月后未处理种皮的种子发芽率极低,撕破种皮后显著地提高了种子发芽率。在水基质条件下,25°C最适宜竹叶眼子菜的萌发,光暗周期对种子发芽率有显著影响。冷藏6个月的种子发芽率最高,8个月时发芽率显著降低,表明竹叶眼子菜的种子不耐贮藏。还讨论了竹叶眼子菜种子休眠与萌发机制的生态学意义。

Potamogeton malaianus is a dominant submersed aquatic macrophyte that has colonized the lakes across the middle and lower reaches of the Changjiang River. Vegetative reproduction is prevalent in P. malaianus and is highly visible, because of the extraordinary capacity of this plant to spread by fragmentation. Because of this, sexual reproduction has been considered of limited importance and little is known about the seed germination of this species. Laboratory studies were conducted on seeds of P. malaianus to determine the substrate, temperature and light requirements necessary for maximum seed germination. Seed germination was also examined in different duration of cold storage. The results showed that few 3-month-old whole seeds germinated in all treatments, but rose after the seed coats were cracked. Optimum germination occurred in a temperature of 25℃ and water substrate. Photoperiod significantly effected the seed germination. Seed retain viability for a short period in the cold storage condition, the highest germination occurred in 6-month storage seeds. The ecological implications of such behavior are discussed.