光照对海菜花(Ottelia acuminata)种子萌发、幼苗生长及生理的影响

为研究滇池海菜花衰退消亡的原因,探讨其恢复的可能性,通过模拟实验研究了光照对海菜花种子萌发和幼苗生长及生理的影响.结果表明光照强度对海菜花种子萌发的影响不显著;光照强度显著影响海菜花幼苗的生长,其中71.8%和91.5%遮光条件下海菜花的平均叶片长度、叶片宽度和株高均显著高于无遮光和97.6%遮光条件下其平均叶片长度、叶片宽度和株高,平均生物量显著高于97.6%遮光条件下其平均生物量;实验中期不同光照条件下,海菜花叶片叶绿素a含量差异显著,其中71.8%遮光条件下海菜花叶片叶绿素a含量显著高于无遮光和97.6%遮光条件下其含量;光照强度对海菜花叶片过氧化物酶活性影响不显著.富营养化导致的水体透明度低、光照强度弱不影响海菜花种子萌发,但影响了海菜花的生长发育和生理特性,进而可能影响了海菜花的繁殖,这可能是滇池海菜花消亡的原因之一.因此恢复海菜花必须提高水体透明度,改善光照强度.

Effects of light intensity on the seeds germination, seedlings growth and physiology of Ottelia acuminata

The effects of light intensity on seeds germination, seedlings growth and physiology of Ottelia acuminata were studied through simulated experiments in order to explore the reasons for the disappearance of the plant in Lake Dianchi in China and the possibilities of its restoration. The results showed that light intensity had no significant effect on the seeds germination, while the influences of different light intensities on the seedlings growth of O. acuminata were significant. The blades length, blades width and plants height under shading rates of 71.8% and 91.5% were all significantly higher than those under 0% and 97.6% shading rates, and the biomass under that two shading rates were also obviously higher than those under 97.6% shading rate. Our results also showed that light intensity had prominent influence on chlorophyll-a content in the middle period of this research, but no remarkable effects were found in the effect of light intensity on peroxidase activities in the leaves. Chlorophyll-a contents in the leaves under shading rate of 71.8% were significantly higher than those under 0% and 97.6% shading rates. Although low water transparency and weak light intensity caused by eutrophication did not influence the seeds germination of O. acuminata, they affected the seedlings growth and physiological characteristics, which may impact the reproduction of the plant eventually. Therefore, it is necessary to increase the water transparency and improve the light condition in order to restore O. acuminata in Lake Dianchi.