摘要
光合速率在日出后随着光强的增强而急速升高,4月20日是小麦光合最强。净光合速率日变化随施氮量的增加而下降,水胁迫处理显著低于高水处理;不同时段变化净光合速率随施氮量和土壤含水量的增加而增加,但总的趋势是降低的。小麦蒸腾速率日变化总体趋势是在日出后随着光强的增强而急速升高、随光强的减弱而降低。小麦蒸腾速率日变化曲线为单峰型,中午最高。叶片蒸腾速率日变化随土壤水分供应增加而增加,随氮肥供应增加而下降;不同供水供氮条件下,叶片蒸腾速率的分异在日中尤其是上午比较明显。蒸腾速率从4月10日一直呈现下降趋势。小麦叶片水分利用率日变化曲线为"L"型,即早上较高,中午和下午都非常低。4月20日叶片水分利用率最高,5月10日最低。叶片对不同土壤水分和氮控制的反映为高氮低水高水分利用率,反之,则水分利用率较低。不同水、氮在上午对叶片水分利用率影响差异比较明显,下午则趋于一致。
Net photosynthetic rate of wheat leaves increased quickly with strengthened radiation at sunrise. The maximum net photosynthetic rate occurred on April 20^(th). Net photosynthetic rate of wheat leaves decreased with increasing nitrogen rate,while soil water stress made net photosynthetic rate significantly lower than no soil water stress. Net photosynthetic rate of growing stages was promoted by more nitrogen supply and soil water control, but reduction of net photosynthetic rate had occurred since April 10^(th). Daytime change of transpiration rate of wheat leaves appeared as single peak. Respective effects of soil water and nitrogen supply on transpiration rate were stimulative and suppressive. Since April 10^(th), transpiration rate of wheat leaves had declined and the decline was more obvious with soil water sapply than with nitrogen supply. Water use efficiency of wheat leaves appeared to be higher in the mornings. Water use efficiency of wheat leaves was highest on April 20^(th), but it was contrary on May 10^(th). Water use efficiency of wheat leaves increased with higher nitrogen supply and lower soil water content. Difference of soil water control to water use efficiency of wheat leaves from nitrogen control was obvious in noon, but it was identical later.
出处
《土壤通报》
CAS
CSCD
北大核心
2004年第2期136-142,共7页
Chinese Journal of Soil Science
基金
国家重点基础发展规划项目(G1999011803)
国家自然科学基金项目(49890330)资助。
