摘要
晴天,利用LI-6400光合仪研究了旱作条件下4年生紫花苜蓿新疆大叶、巨人201、牧歌401和路宝再生草初花期(2004年6月23日)的光合作用日变化特征。结果表明:①4个苜蓿品种Pn、Tr和Gs的日变化曲线均呈“双峰”型,12:00左右存在明显的光合“午休”现象,但不同品种Pn、Tr和Gs的高峰和低谷出现的时刻和高低不同。WUE日进程,除路宝呈“单峰”型外,新疆大叶、巨人201和牧歌401呈“双峰”型,4个品种在8:00左右的WUE均达到全天的最高值,14:00左右的峰值不明显。②根据Pn、Ci、Ls的变化方向,推测4个品种的光合“午休”主要受气孔因素限制。③国外苜蓿品种巨人201、牧歌401和路宝日平均Pn、Tr和WUE均优于国内地方品种新疆大叶,尤其是巨人201是一种高光合、高蒸腾、高水分利用率的品种。④相关分析结果表明,对Pn影响最显著的因子是PAR,其次是Gs、RH、Ta和VPD;对蒸腾速率影响最显著的因子为PAR,其次是RH、Ta、Gs和VPD。
On fine days, daily dynamics of photosynthetic characteristics in four alfalfa varieties under dry farming conditions were monitored using Portable LI-6400 Photosynthesis System. The four alfalfa varieties included Xinjiang big leaf, Ameristand 201, Arnerigraze 401 and Lobo, which were at the flowering stage after the first cutting in their fourth year of growth. The results were summarized as follows ： ① The curves of diurnal variation in Pn, Tr and Gs of four alfalfa varieties leaves had two peaks, and an obvious midday depression at 12：00 o＇ clock, although there were differences in the time and the value of the peaks occurred in terms of Pn, Tr and Gs. WUE had two peaks in all the varieties except in Lobo, and the four alfalfa varieties all reached the highest value of WUE at 8：00 o＇clock. ②Based on the tendency of changes in Pn, Ci, Ls, it was speculated that the midday depression in the alfalfa varieties was controlled by stomatal factor. ③Daily average values in Pn, Tr and WUE of Ameristand 201, Arnerigraze 401 and Lobo were higher than Xinjiang big leaf, with Ameristand 201 being the best. ④ Correlation analyses showed that the factors affecting Pn could be ranked, from the highest to the lowest, as PAR 〉 Gs 〉 RH 〉 Ta 〉 VPD, and the factors affecting Tr could be ranked as PAR 〉 RH 〉 Ta 〉 〉 Gs 〉 VPD.
出处
《生态学报》
CAS
CSCD
北大核心
2006年第5期1468-1477,共10页
Acta Ecologica Sinica
基金
国家农业部948资助项目(2001-372)~~
关键词
苜蓿
旱作
光合速率
蒸腾速率
水分利用效率
气孔导度
alfalfa
dry fanning
photosynthetic rate
transpiration rate
water use efficiency
Stomatal conductance
