昼夜温差对番茄幼苗光合特性和物质积累的影响

为了深入了解昼夜温差对番茄幼苗光合作用影响的机理,试验利用微电脑人工气候箱,在昼夜平均温度20℃的情况下,研究了昼/夜为20℃/20℃、23℃/17℃、26℃/14℃这3个不同温差(0,6,12℃)对番茄幼苗光合生理特性和物质积累的影响。结果表明,26℃/14℃处理比20℃/20℃处理可增加番茄幼苗单叶面积30.3%～47.1%,提高叶片净光合速率87.5%～126.6%,增加番茄幼苗干物质48.8%～55.7%;同时,显著增加了气孔导度和气孔限制值,显著降低了胞间CO2浓度;23℃/17℃处理也可以一定程度上增加幼苗的净光合速率和物质积累。昼夜平均温度20℃时,适当加大昼夜温差,能显著降低光合作用的非气孔因素限制,促进光合作用;并能增加单叶面积和单位面积叶绿素含量,增加番茄幼苗的物质积累。

Effects of Difference between Day and Night Temperature on Photosynthesis Mechanism of Tomato Seedlings

To understand the mechanism of effects of temperature difference between day and night on photosynthesis of tomato seedlings,two experiments were carried outwith climate box(SPX-250IC)under the average temperature of 20℃ in April and May,2010.Day/night temperature were 20℃/20℃,23℃/17℃ and 26℃/14℃,and difference between DT and NT were 0,6 and 12℃.The results showed that net photosynthetic rate(Pn),single leaf area,contents of chlorophyll and dry matter accumulation were increased with the increasing of difference between day and night temperature,while average of 24h air temperature was uniform.Area of single leaf increased 30.3%~47.1%,Pn increased 87.5%~12.6%,and dry weight increased 48.8%~55.7% under 26℃/14℃ than that of 20℃/20℃.Meanwhile,stomata conductance(Gs)and Ls increased greatly,but intercellular CO2 concentration(Ci)decreased greatly under 26℃/14℃ than that of 20℃/20℃.Pn,leaf area and dry weight of tomato seedlings increased under 23℃/17℃ than that of 20℃/20℃,too.It was suggested that limiting factors of non-stomata of tomato seedlings reduced,photosynthesis and accumulation of matter increased,single leaf area and chlorophyll contents increased under 26℃/14℃ compared with that of 20℃/20℃.