张美微 李志源 鲁振 乔江方 刘京宝 李川 张盼盼 赵霞 牛军 黄璐

摘要：【目的】探討吐丝期干旱胁迫造成夏玉米减产的叶绿素荧光生理机制，为夏玉米抗旱栽培提供理论依据。【方法】以夏玉米品种郑单958和先玉335为试验材料，利用具有遮雨棚的抗旱池，设充分灌水[CK，0～20 cm土层含水量为田间最大持水量的（75±5）%]和吐丝期干旱胁迫[0～20 cm土层含水量为田间最大持水量的（45±5）%]2个处理。测定吐丝期（0 d）及吐丝后10、20和40 d穗位叶叶片SPAD值及叶绿素荧光参数，调查成熟后穗部性状及产量。【结果】吐丝期干旱胁迫显著降低了夏玉米吐丝期及吐丝后的叶片SPAD值，以吐丝后20 d 降幅最大，分别为15.38%（郑单958）和17.65%（先玉335）。干旱胁迫下，2个夏玉米品种穗位叶光系统Ⅱ（PSⅡ）最大光化学效率（Fv/Fm）和PSⅡ潜在活性（Fv/Fo）均显著下降（P<0.05，下同），且随着干旱胁迫时间延长而加剧，以吐丝后20 d降幅最大，分别达0.036和0.574（郑单958）、0.039和0.593（先玉335）。同时，干旱胁迫还降低了穗位叶光合性能综合指数（PIABS），影响程度随着干旱胁迫时间的延长而加剧，以吐丝后20 d胁迫强度最大，分别降低12.30%（郑单958）和16.87%（先玉335）。此外，在干旱胁迫结束恢复供水后，干旱胁迫处理吐丝后40 d的叶片叶绿素含量和叶绿素荧光参数仍低于CK，但与CK间差距缩小。干旱胁迫增加了2个夏玉米品种秃尖长，显著降低了穗粒数和千粒重，最终导致郑单958和先玉335分别显著减产10.29%和11.83%。【结论】吐丝期干旱胁迫对夏玉米穗位叶叶绿素造成了不可逆的损伤，导致叶片SPAD值、Fv/Fm、Fv/Fo和PIABS显著下降，限制叶片光合作用，造成减产。

关键词： 夏玉米;吐丝期干旱;叶绿素荧光特性;产量

中图分类号： S513                                  文献标志码： A 文章编号：2095-1191（2021）04-0924-07

Effects of drought stress on chlorophyll fluorescence

characteristics and yield of summer maize at silking stage

ZHANG Mei-wei1， LI Zhi-yuan2， LU Zhen3*， QIAO Jiang-fang1， LIU Jing-bao1，

LI Chuan1， ZHANG Pan-pan1， ZHAO Xia1， NIU Jun1， HUANG Lu1

（1Cereal Crops Institute， Henan Academy of Agricultural Sciences， Zhengzhou  450002， China; 2Yuzhou Agricultural Machinery Technology Center， Yuzhou， Henan  461670， China; 3Agricultural Technology Extension Station

of Henan Province， Zhengzhou  450002， China）

Abstract：【Objective】Discussed the chlorophyll fluorescence physiological mechanism of summer maize yield deduction caused by drought stress at silking stage and provided theoretical basis for drought resistant cultivation of summer maize. 【Method】The summer maize cultivars of Zhangdan 958 and Xianyu 335 were used as test materials. The experiment with two water treatments of sufficient irrigation[CK， the soil moisture content was（75±5）% of the maximum field water capacity in 0-20 cm soil layer] and drought stress[the soil moisture content was（45±5）% of the maximum field water capacity in 0-20 cm soil layer] were applied in drought pool with rain shelter. Determined the SPAD value and chlorophyll fluorescence parameters of ear leaf at silking stage（0 d） and after silking stage， and investigated the spike characters and yield of summer maize. 【Result】Drought stress significantly influenced the SPAD value and chlorophyll fluorescence characteristics. Drought stress declined leaf SPAD value at silking stage and after silking stage，and the biggest decline of Zhengdan 958 and Xianyu 335 with 15.38% and 17.65% respectively occurred at 20 d after silking. Under drought stress， photosystemⅡ（PSⅡ） maximum photochemical efficiency（Fv/Fm） and potential activity（Fv/Fo） of ear leaves of the two summer maize varieties  declined significantly（P<0.05， the same below）， and the decline was strengthened as drought stress time extended. The decline at 20 d after silking was the largest， which were 0.036 and 0.574 respectively for Zhengdan 958，0.039 and 0.593 respectively for Xianyu 335. Simultaneously，drought stress decreased index of photosynthetic performance（PIABS）of ear leaf，the influence was enhanced as drought stress time extended. The most decline were achieved at 20 d after silking with 12.30% and 16.87% respectively for Zhengdan 958 and Xianyu 335. Additionally，when water supply was restored after drought stress，leaf chlorophyll content and chlorophyll fluorescence parameters （Fv/Fm， Fv/F0 and PIABS） at 40 d after silking under drought stress were lower than CK， but the difference between the two treatments was dwindled. Drought stress extended bald ear length，decreased kernels per spike and thousand-kernel weight significantly，resulted in reduction of yield by 10.29% and 11.83% respectively for summer cultivar of Zhengdan 958 and Xianyu 335. 【Conclusion】Drought stress at silking stage causes the irreversible damage to chlorophyll in ear leaves，which decreases SPAD value，Fv/Fm，Fv/F0 and PIABS，restricts leaf photosynthesis，and results in reduction of output for summer maize.

Key words： summer maize; drought at silking stage; chlorophyll fluorescence characteristics; yield

Foundation item： National Key Research and Development Program of China（2018YFD0300702）; National Natural Science Foundation of China（31701368）; Independent Innovation Project of Henan Academy of Agricultural Sciences（2019ZC07，2020ZC10）

0 引言

【研究意义】黄淮海平原夏玉米生长季气温高、水分蒸发量大，随着我国水资源不断减少及降雨时空分布不均的发生，造成夏玉米干旱发生频率高达64.36%以上，成为危害夏玉米生产的主要气象灾害之一（薛昌颖等，2016）。夏玉米在拔节到抽雄期间需水量迅速增加，到抽雄至灌浆期达最高值（刘战东等，2013）。在作物响应干旱胁迫的生理过程中，光合作用是第一个环节（Nielsen et al.，2009），而叶绿素荧光参数能全面反映光系统Ⅱ（PSⅡ）的原初光化学反应和光合机构状态变化，是研究逆境胁迫下光合作用的有效工具（杜伟莉等，2013）。因此，研究吐丝期干旱对夏玉米叶绿素荧光特性和产量的影响，探讨干旱胁迫影响PSⅡ原初光化学反应的生理机制，对夏玉米抗旱品种培育和抗旱节水栽培均具有重要意义。……