三峡水库消落区周期性水淹对狗牙根非结构性碳水化合物积累与分配的影响

Effects of Seasonal Submergence on the Accumulation and Allocation of Non-structural Carbohydrate of Cynodon dactylon(Linn.) Pers. in the Water-fluctuation-zone of Three Gorges Reservoir

水淹胁迫下,非结构性碳水化合物在植物组织内的积累水平和分配模式对植物的逆境适应能力起着关键性作用。本文以三峡水库消落区内具有典型代表性的适宜多年生草本植物——狗牙根[Cynodondactylon(Linn.)Pers.]为研究对象,在海拔高程151~152 m上,对不同年限适应株根、地上茎、匍匐茎和叶非结构性碳水化合物净增长量以及其他相关指标进行测定,分析周期性水淹对狗牙根非结构性碳水化合物积累与分配的影响。结果表明:(1)50 d恢复生长期间不同年限适应株地上茎无显著性伸长生长;最大叶片长均显著小于正常生长植株。(2)不同年限适应株叶片数及总叶绿素含量呈先增高后降低趋势,出水40 d,50 d时不同年限适应株叶片数与正常生长株相比无显著性差异。(3)不同年限适应株根、地上茎、匍匐茎及叶非结构性碳水化合物均呈一定程度积累,尤其是多年适应株净增长量总体上高于两年适应株、三年适应株及正常生长株。(4)周期性水淹显著改变不同年限适应株非结构性碳水化合物分配模式,与正常生长植株相比匍匐茎分配量总体增加,尤其是多年适应株不同测量点非结构性碳水化合物净增长量均显著大于根、地上茎及叶。结论:周期性水淹不仅使狗牙根在恢复生长期间积累一定量非结构性碳水化合物,同时亦改变其非结构性碳水化合物分配模式,进而有利于植株增强水淹胁迫耐受性。

The accumulation and allocation of non-structural carbohydrate in plant plays a critical role in cultiva-tion of plant＇s stress adaptive capacity under submergence stress. This paper focused on the typical perennialherbs Cynodon dactylon（Linn.） Pers. adaptively located at the elevation 151~152 m in the water level fluctua-tion-region of Three Gorges Reservoir. The net growth of non-structural carbohydrate content in its root, aerialstem, stolon, and leaf, and the other related indexes were measured to reveal the effect of seasonal submergenceon the carbohydrate accumulation and allocation. For the herbs of different years, their aerial stems in the recov-ery period of 50 days after emerging from the water level had no significant elongation, and their maximum leaflengths were significantly shorter than those of the ones growing at normal conditions. Their leaf numbers rapidlyincreased in the first 5~20 days, and then decreased. After the 50 days recovery, their total chlorophyll contentswere significantly lower than those of the normally growing ones. Overall, non-structural carbohydrate was accu-mulated in the root, aerial stem, stolon, and leaf for Cynodon dactylon（Linn.） Pers.of different years. Especially,the accumulation in the multi-years herbs was significantly higher than that of the ones of two or three years, aswell as at the normal conditions. The allocation behavior of non-structural carbohydrate was changed by season-al submergence for Cynodon dactylon（Linn.） Pers. of different years. The net growth of non-structural carbohy-drate content in stolon increased, and was significantly higher for the herbs of multiple years in comparison withnormally growing ones. The results showed that seasonal submergence not only induced non-structural carbohy-drate accumulation, but also changed the allocation behavior for Cynodon dactylon（Linn.） Pers.