珍稀濒危植物蛛网萼的种子形态及萌发特性

摘要

In this paper the biological characteristics of Platycrater arguta seed germination were studied aiming to understand the underlying mechanisms relevant to the impediment in the regeneration of P.arguta population.Base on the analysis of the anatomical structure of the seeds and seed coats,the effects of different temperature,storage time and different concentrations of GA3 on the germination of P.arguta.were studied.Sim-ulation test results showed that GA3 exhibited promotion effect on the seed germination,high germination rate and early germination time were achived with high GA3 concentration (1 000 mg/L).25℃ was the optimal temperature for the seed germination of P.arguta.But along with extended cold storage time,the seed germi-nation rate decreased.To sum up the above results,the immediate causes that made it difficult for the natural populations of P.arguta to regenerate may be inferred as follows:the small size of seeds would impose restric-tion for its success in competition with other plant species;the seeds of P.arguta germinted slowly even under optimum conditions,and the germination velocity was low,and the germination was uneven;the germination had high requirement of temperature,light and moisture;seed coat hindered seed germination.All the above might be the main causes for the endangerment of the species.%研究蛛网萼种子萌发的生物学特性，以了解该种在自然条件下更新困难的原因和使其致濒的机制。在对其种子种皮解剖结构分析的基础上，开展不同赤霉素质量浓度、不同浸泡温度以及贮藏时间对蛛网萼种子萌发影响的研究。模拟试验结果表明赤霉素对种子萌发有促进作用，较高浓度赤霉素（1000 mg／L）处理下萌发最早且发芽率最高；浸泡水温为25℃，发芽情况最好；随着冷藏时间延长，种子萌发率越低。综合来看，种子萌发特性导致蛛网萼在自然条件下更新困难的原因可能是：蛛网萼种子小虽然能够占有更多的安全位，但在竞争中处于劣势；种子在合适的条件下萌发速度慢，发芽率低，萌发不整齐；种子萌发对温度和水分的要求高，适应范围狭窄；种皮对种子萌发的阻碍。这些因素可能是导致该物种濒危的重要原因。