Roots of Nymphoides peltata collected from Lake Taihu were cultured under three different temperatures (28,30,32℃).The biomass under such different temperature conditions were 0.0019 ± 0.0002,0.0021 ± 0.0003 and 0.0020± 0.0003 g (DW)/cm2,respectively.Meanwhile,the dry weight of stem and root was maximum under 30℃ than other treatments that had significant difference; the order of the dry weight and biomass per unit area of leave was 30℃ ＞ 28℃ ＞ 32℃.Light response curves and ACI curves were determined by a Li-6400 portable photosynthesis analysis system,and the non-rectangular hyperbolic method was used to fit the curve to obtain relevant photosynthetic parameters.The results showed that the influences of temperature on order of N.peltata photosynthetic capacity was 30℃ ＞ 32℃ ＞ 28℃,the order of carboxylation efficiency was 32℃ ＞ 30℃ ＞28℃,transpiration efficiency and stomatal conductance showed the same trend,30℃ ＞ 28℃ ＞ 32℃.The photosynthetic capacity of N.peltata increased significantly with the increasing temperature,and the growth of N.peltata was promoted;however,the photosynthetic efficiency reduced when the temperature exceeded 30℃ with the suppression of N.peltata.In the appropriate temperature range(＜ 30℃),small amplitude wanning(2℃) produced a significant effect of accumulated temperature (200℃ · d),which promote the growth of N.peltata.It is deduced that the phenomenon that the average temperature of Lake Taihu increased about 1 ℃ during 1998-2006 may promote the expansion of N.peltata in Lake Taihu in recent years.%以太湖东山与西山之间水域的善菜根茎为实验材料,在室内分别进行3种温度(28、30、32℃)处理,利用Li-6400便携式光合作用测量系统,分别测定3种温度处理下善菜的光响应曲线和CO2响应曲线,并且利用非直角双曲线法进行拟合,得到相关参数.结果表明,3种温度下,善菜的光合能力大小顺序表现为30℃＞32℃＞ 28℃,羧化效率为32℃＞30℃＞28℃,蒸腾速率、气孔导度均为30℃＞28℃ ＞32℃;28、30和32℃下的单位叶片生物量分别为0.0019±0.0002、0.0021±0.0003、0.0020±0.0003 g(DW)/cm2,叶片及其单位面积生物量为30℃＞28℃＞32℃,但差异不显著;30℃下的根、茎干重显著高于另外2个温度下的.在低于30℃的温度条件下,随着温度的升高,善菜的光合能力均明显升高,促进了植物的生长;而当温度超过30℃后,光合作用效率降低,植物的生长则受到抑制.在适宜温度范围内(＜30℃),小幅度的升温(2℃)产生了显著的积温效应(200℃·d),促进了善菜的生长.因此推断,1998-2006年太湖地区平均气温升高约1.0℃的现象对近年来太湖善菜的大面积扩张可能具有促进作用.
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