不同光照条件对菹草外部形态与内部结构的影响

陈小峰; 王庆亚; 陈开宁

不同光照条件对菹草外部形态与内部结构的影响

Impacts of Different Light Intensity on Morphology and Structure of Potamogeton crispus

摘要

摘要: 通过受控试验,研究了4个光照处理(100%、50%、20%、10%的自然光)对菹草(Potamogeton crispus)外部形态与内部结构的影响。结果显示:(1)100%和50%自然光处理对菹草的总生物量影响不显著,20%和10%的自然光显著降低了菹草的总生物量。(2)在生物量分配方面,50%自然光处理的根冠比值显著低于其他3个处理组,表现出菹草对地上部分茎叶生物量的投资较多。(3)在50%自然光条件下,菹草的株高、植株叶片数、顶枝叶片数明显高于其他3个处理组的对应参数,说明适当的遮荫会促进菹草植株的生长;10%自然光下的各参数值均最小(除根/冠比值),表明已较严重地限制了菹草的正常生长。(4)20%和10%自然光的遮光处理增加了菹草的叶片厚度,100%、50%、20%和10%的自然光下分别为0.260、0.297、0.440、0.306mm。(5)100%自然光叶片的叶肉细胞没有形成发达通气组织,50%自然光的菹草叶肉细胞开始形成较发达的通气组织,通气组织中间隔分布有单层细胞组成的隔膜,20%和10%自然光的叶片中隔膜细胞破裂,形成了发达的通气组织;20%和10%自然光的叶片通气组织细胞面积显著大于100%和50%自然光处理组,均值分别为0.558mm²、0.284mm²和0.108mm²、0.087mm²。(6)20%自然光处理组根的表皮细胞中可以发现四端尖锐晶体存在,表明植物生长受到一定程度胁迫;50%自然光处理的根通气组织彼此相连,形成大的通气结构,而其它处理组皮层没有形成通气结构。综合上述研究结果表明,50%自然光处理较有利于菹草的生长发育。

Abstract: With mesocosm experiment effects of different light intensity on morphology and structure of Potamogeton crispus were studied.The results showed that the mean difference in the total biomass of P.crispus under the condition of 100% and 50% of natural light intensity(NLI) was not significant.The total biomass of P.crispus was markedly decreased with the treatment of 20% and 10% NLI.In biomass distribution,rates of root/shoot with treatment of 50% NLI were much higher than other treatments,which indicated more biomass was distributed to above-ground shoot.Height of shoot,number of leaf and number of leaf in canopy of P.crispus with the treatment of 50% NLI were much more than other treatments,which showed the treatment of 50% NLI facilitated growth of this species,but the treatment of 10% NLI restrained growth of P.crispus.The thickness of leaf in P.crispus increased under the condition of the treatment of 20% and 10% NLI.The thickness of leaf with the treatment of 100%,50%,20% and 10% NLI were 0.260 mm,0.297 mm,0.440 mm and 0.306 mm,respectively.With the treatment of lower light intensity,mesophyll cells became bigger,and mesophyll cells shaped bigger ventilating tissue.Cell area of ventilating tissue with the treatments of 100%,50%,20% and 10%NLI were 0.108 mm²,0.087 mm²,0.558 mm² and 0.284 mm²,respectively,which showed that the treatments of 20% and 10% NLI were much more than those of 100% and 50% NLI.Crystals were observed in epidermis cells of root with the treatment of 20% NLI.The bigger ventilating structure was observed in cortex of root with the treatment of 50% NLI,but this structure did not existed in other treatments.The results indicated the treatment of 50% NLI was in favor of growth of P.crispus.

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