枇杷种子脱水敏感性的初步研究

枇杷（EriobotryajaponicaL.）种子成熟采收时含水量高达58.7％，其中子叶含水量为55.3％，胚轴的含水量为73.2％。新鲜种子的发芽率和活力指数分别为90％和0.81。轻度脱水能较大幅度地提高发芽率和活力指数。但随着脱水程度的不断加深，子叶和胚轴的超氧物歧化酶（SOD）活性下降，丙二醛（MDA）含量和种子浸泡液的电导率增加，种子活力迅速降低。当子叶和胚轴的含水量分别降至35.5％和28.0％时，种子发芽力完全丧失。枇杷种子脱水敏感的一个重要原因就是在脱水劣变过程中，发生了膜脂过氧化作用，从而使膜脂含量下降，膜结构和功能受损，最终导至种子活力丧失。

Primary Studies On Desiccation-Sensitivity of Loquat Seeds

Loquat(Eriobotrya japonica L.) seeds contained as high as 58.7% moisture content when taken from ripened fruits. The moisture content of cotyledon was 55. 3% and that of embryonic axis was 73.2%. The fresh seeds had the germination percentage of 90% and the vigor index of 0. 81, which could be increased by light desiccation. With more water lost, seeds vigor decreased rapidly. the activitied of superoxide dismutase (SOD) also decreased, while the conductivity of seeds and the contents of malon aldehyde (MDA) increased dramamtically. The ability of germination lost completely when the moisture content of cotyledon was 35.5 % (28.0 % in embroynic axis). The reason why loquat seeds werr sensitive to desiccation could be that peroxidation of membrane lipids and inactivation of membrane proteins occured during water lost. Therefore, structure and function of membrane were great damaged, viability of seeds was lost.