以江苏省农业科学院太湖雪堰、南京和滇池白山湾的试验点内种养的凤眼莲为研究材料,在相同种养时间内,统一测定不同地区植株的株高和干重的变化及不同叶位光合参数和光合功能叶片的光合—光响应曲线等,以期阐明不同生态区凤眼莲株型特征形成的生态生理机制,并为不同地区人工放养凤眼莲的高产栽培提供理论参考和技术支持.结果表明:(1)不同地区种养的凤眼莲株型有较大差异,滇池的为短地上部分和长根的株型,其茎叶长/根长为0.4土0.1；南京的为中等长度的地上部分和短根的株型,其茎叶长/根长为7.1±0 3；太湖的为长地上部分和中等根长的株型,其茎叶长/根长为2.0±0.2.(2)形态有差异的不同地区凤眼莲植株的光合表现存在差异,与南京和滇池地区的相比,太湖凤眼莲不同叶位的净光合速率(Pn)最高(25.9～35.3μmol.m-2·s-1)；相关性分析表明,南京凤眼莲的Pn与其相对湿度呈极显著负相关(r=-0.831**,n=6),滇池凤眼莲的Pn与气孔导度呈显著正相关(r=0.769*,n=6),太湖凤眼莲的相对湿度与叶片蒸腾速率呈显著负相关(r=-0.818*,n=6).可见影响不同地区Pn的外界因子有差异,但除外界光强外,相对湿度也是影响其Pn高低的重要生态因子.(3)不同生态地区形态有差异的植株己形成了相应的光合潜力,生长能力最强的太湖地区植株,光合能力也最强,Pmax最大(36.29±1.21μmol·m-2·s-1)且光饱和点最高(LSP,2 350.0±69.0 μmol·m-2·s-1)；相关性分析进一步表明,株高和光补偿点(LCP)以及茎叶长度与光饱和点均呈显著正相关,相关系数分别为r=0.998*、r=0.997*(n=10).本研究可为不同地区利用凤眼莲净化富营养水域的高产栽培提供参考.%Eichhornia crassipes Solms, commonly known as water hyacinth, is a bundler aquatic plant. It is widely used in sewage purification due to its well developed root system, strong reproductive ability and ultra-strong absorbency. Introduced into China as feed, it is recently moderately consumed as cultivation substrate of edible fungus and methane fermentation materials. In fact, it is now an importantly modem, low-carbon eco-agricultural resource. An experiment was therefore conducted to determine the physiological and ecological characteristics of different types of water hyacinth in different ecological environments. The experiment was carried out at the Jiangsu Academy of Agricultural Sciences experimental sites in Xueyan of Taihu Lake, Nanjing and Dianchi Lake in 2009. Different plant indices such as plant height, root length and dry weight were measured. Also photosynthetic parameters of leaves at different sits were measured using LI-6400 portable photosynthetic system. The related environmental factors such as light intensity, air temperature and relative humid were recorded as well. Different water hyacinth phenotypes were noted in different areas.Short shoot with long root water hyacinths were noted in Dianchi Lake (with shoot/root height ratio of 0.4±0.1). Then medium-long shoot with short root water hyacinths were observed in Nanjing (with shoot/root height ratio of 7.1 ±0.3). Also long shoot with medium-long rool water hyacinths existed in Taihu Lake (with shoot/root height ratio of 2.0±0.2). Compared with those in Nanjing and Dianchi Lake, Pn (25.9-35.3 μmol-m-2s-1) of water hyacinth at Taihu Lake was the highest for different leaf positions. The correlation coefficients between Pn and relative humidity in Nanjing, Pn and stomatal conductance (Gs) in Dianchi Lake, and relative humidity and transpiration rate (Tr) in Taihu Lake were -0.831 , 0.769 and -0.818 (n=6), respectively. Correlation analysis showed that after light intensity, relative humidity was the next most important ecological driving factor of Pn. Difference in phenotype of water hyacinth in different areas had affected maximum photosynthetic potentials of water hyacinth. The strongest plant growth of water hyacinth in Taihu Lake was related with high photosynthetic capacity (Pmax=36.29±1.21 μmolm-2's-1) and light saturation point (LSP=2 350.0±69.0 pmol-m-2's-1). Plant height and light compensation point (LCP), as well as shoot length and LSP were all positively correlated with correlation coefficients of 0.998 and 0.997 (n=l0), respectively. The findings of the study were critical for high yield artificial stocking of water hyacinth. It was recommended that future breeding should focus on extensive adaptability of E. Crassipes to light and temperature conditions.
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