狗牙根种子对模拟水淹的生理及萌发响应

The Physiological and Germination Responses of Cynodon dactylon Seeds to Simultaneous Submergence

在实验室模拟条件下,将种子水淹0d、7d、14d、21d、28d和35d,分析水淹时间对种子含水量、千粒重以及丙二醛(MDA)、可溶性糖和淀粉含量、最终萌发率、萌发指数、开始萌发时间和萌发高峰期的影响,探索狗牙根种子对水淹的生理及萌发响应。结果表明:(1)种子含水量随水淹时间延长由8.85%显著上升至20.89%(P<0.05,下同);(2)种子千粒重和淀粉含量随水淹时间的延长而下降,在水淹35d时分别由0.2793g和525.14mg/g下降至0.1757g和223.39mg/g;(3)种子可溶性糖含量在水淹14d时上升到最大值(86.01mg/g)后开始下降,水淹35d时下降到最低值25.99mg/g;(4)各处理组种子MDA含量无显著差异;(5)随水淹时间的延长,种子相对萌发率和相对萌发指数下降,开始萌发时间和萌发高峰期推迟,水淹28d后种子丧失萌发力。水淹导致狗牙根种子过度消耗,未造成膜脂过氧化伤害;水淹7d为种子萌发力的临界值。

To explore the physiological and germination responses of Cynodon dactylon to submergence,the seeds were submerged for 0,7,14,21,28 and 35 days on laboratory simulation condition.Besides the effects of submergence duration on the seed moisture content,thousand seeds weight,and the content of MDA,soluble sugar and starch as well as the effects on final germination rate （FGR）,germination index （GI）,time to start germination （TSG）,peak period of germination （PPG）,germination duration （GD） were analyzed.The results showed that seed moisture content increased significantly （P〈0.05,the following is the same.） from 8.85% to 20.89% with the duration of submergence.Both thousand seeds weight and starch content decreased significantly from 0.2793g and 525.14 mg/g to 0.1757g and 223.39 mg/g at 35d,respectively.After the soluble sugar content increased to maximum （86.01 mg/g） on the 14th day,the content began to decrease,and the minimum （25.99 mg/g） occurred at 35d.There were no significant differences among the MDA contents of treatment groups.As submergence extended,seed relative germination rate （RGR） and relative germination index （RGI） were decreased,time to start germination （TSG） and peak period of germination （PPG） were delayed,and seeds lost germination ability on the 28th day.Submergence resulted in excessive consumption of substances stored in Cynodon dactylon seeds,but did not cause membrane lipid peroxidation.And 7 days of submergence is threshold of seed germination ability.