水氮耦合对小麦旗叶光合特性及籽粒产量的影响

Coupling Effects of Water and Nitrogen on Photosynthetic Characteristics and Kernel Yield of Wheat

在盆栽条件下,以旱地小麦品种‘长旱58’为材料,研究水氮耦合对冬小麦旗叶主要光合特性及小麦籽粒产量的影响。结果表明,在2种水分处理下小麦旗叶的叶绿素SPAD值、净光合速率（Pn）、气孔导度（Gs）、蒸腾速率（Tr）及产量等都随氮肥施用量增加而增加,氮肥主要通过影响小麦旗叶Pn和小麦的穗数、穗粒数来影响产量。在不施氮（N0,0g·kg^-1）及正常施氮（N1,0.2g·kg^-1）处理下,中度水分胁迫（W2,土壤含水量为田间持水量的50%~60%）处理的小麦旗叶的光合速率及产量大于充分灌溉处理（W1,土壤含水量为田间持水量的70%~80%）,而在高氮（N2,0.4g·kg^-1）处理下则相反。说明,适度水氮运筹会提高小麦旗叶光合能力及籽粒产量形成,主要表现为粒质量的增加。

The wheat cultivar Changhan 58 was used to investigate coupling effects of water and nitrogen on photosynthetic characteristics of flag leaf and grain yield through systematic experiments under pot conditions.The results indicate that the photosynthetic characteristics including relative chlorophyll content（SPAD value）,photosynthetic net rate（Pn）,conductance（Gs）,transpiration rate（Tr）and grain yield increased with increasing nitrogen amount application under two water treatments,nitrogen affect the grain yield is mainly through the influences of flag leaf photosynthetic rate,spike numbers and kernels of per spike of winter wheat.Under the nitrogen 0（0g·kg^-1）and normal nitrogen level（0.2g·kg^-1）treatments,moderate water stress（soil water content was 50%-60% of the field capacity）enhanced the flag leaf photosynthetic rate and grain yield compared to the full irrigation treatment（soil water content was 70%-80% of the field capacity）,while the opposite conclusions was obtained under high nitrogen treatment（0.4g·kg^-1）.The results indicat that moderate water and nitrogen coupling can improve the wheat flag leaf photosynthetic capacity and grain yieldformation,mainly for the increase of kernel mass.