温度对栾树秋叶变色的影响

Effects of Temperature on Discoloration of Autumn Leaves of Koelreuteria paniculata

利用SPAD指数,考察温度对2011年秋季北京市区内典型秋季树种——栾树秋叶变色的响应程度。结果表明,昼夜温差对栾树SPAD数值的影响并不显著,最低温对栾树SPAD数值的影响极显著。当日最低温在10℃至5℃之间的积累天数超过10 d时,有利于栾树变色。当日最低温低于12℃时,叶片开始变色,在9℃左右时效果最好,在8℃以下时,叶片近全变色。

The SPAD index was used to investigate the response degree of temperature on discoloration of autumn leaves of Koelreuteria paniculata,a typical autumn tree in Beijing City.The results indicated that the temperature gap between day and night did not affect SPAD values of Koelreuteria paniculata significantly,but the lowest temperature extremely influenced SPAD values of Koelreuteria paniculata.When the accumulated days with the lowest temperature ranged from 10℃ to 5℃ exceeded 10 d,it is benefit for discoloration of Koelreuteria paniculata leaves.When accumulated the lowest temperature was not higher than 12℃,the leaves started to discolor,and the best discoloration effect was around 9℃.When temperature was lower than 8℃,the leaves were nearly all discoloration.