北疆高产棉田棉叶呼吸作用及其与光合作用关系的研究

Respiration of Cotton Leaves and Its Relation to Phyotosynthesis in North Xinjiang

在田间自然条件下，测试了北疆高产（２０００ｋｇ·ｈｍ－２）棉田棉叶的呼吸速率（Ｒ）和净光合速率（Ｐｎ）。结果表明，（１）高产棉田花铃期棉叶夜晚呼吸消耗比普通棉田低２６．２％，但白天净光合总量比普通棉田高４６．１％。高产田夜晚呼吸消耗占日间总光合量的８．３９％，低于普通棉田（１５．４７％）。（２）正常条件下，北疆棉田棉叶日间暗呼吸量／总光合量比值约为３０％～４０％。（３）Ｒ随温度的升高而增强，在北疆高产棉区两者的回归关系日间为Ｒ日＝－０．０８８＋０．３８７ＴＬ，ｒ＝０．３０５，ｎ＝２１８，Ｐ＜０．０１；夜晚Ｒ夜＝－１０．８２４＋０．６３３ＴＬ，ｒ＝０．６６４，ｎ＝３４，Ｐ＜０．０１，夜晚气温低是北疆棉花产量高的重要原因之一。（４）棉株叶片呼吸的空间分布随功能叶的转移而变化，花铃期和吐絮期Ｒ表现为生育前期大于生育后期，果枝叶大于主茎叶，中上层主茎叶大于下层叶。（５）棉花单叶呼吸作用具明显的午休现象，其日变化趋势与Ｐｎ变化大致相当，两者相关系数ｒ＝０．９４３＊＊，北疆棉区棉叶的光合午休以及下午Ｐｎ明显低于上午的现象不是呼吸作用造成的。（６）新陆早７号夜晚Ｒ显著高于新陆早４号。（７）土壤缺水使Ｒ和Ｐｎ均降低，且吐絮?

The dark respiration rate (R) and net photosynthetic rate (Pn) of cotton leaves at bearing boll and early boll-opening stages were studied under the meteorological condition of the high yield (2000kg·hm -2 ) cotton field in North Xinjiang. The results showed that (1) The R of high yield cotton was 26 2% lower than that of common cotton (CK) in night time, but total photosynthetic amount was 46 1% higher at bearing boll period. The ratio of respiration consumption in night time and total photosynthetic amount in high yield cotton was 8 39% ,and 15 47% in CK. (2) The ratio of dark R and total photosynthetic amount of cotton leaf in daytime was about 30%￣40% in North Xinjiang. (3) The regression relation between R and leaf temperature (T L) could be expressed as: R indaytime =-0 088+0.387T L,r=0.305,n=218,P<0.01;R innight =-10.824+0.633T L,r=0.664,n=34,P<0.01. (4) The distribution of leaf R in a cotton plant appeared higher R value at early stage than the later, upper ones than lower leaves on main stem, sympotium branch leaves than those on the main stem at late stage. (5) Midday depression in respiration was observed. The diurnal variation of R showed no significant difference with that of Pn. The correlation coefficients between R and Pn was 0 943. It was recognized that the midday depression of photosynthesis was not due to the respiration. (6) By means of analysis of variance with experimental results obtained in study, the R of Xinluzao 7 was higher than that of Xinluzao 4 significantly at 1% level. (7) Under water stress, the leaves of cotton showed lower R, Pn and higher R/(R+Pn) at early boll opening stages.