| 摘要: |
| 为探究灌浆阶段干旱胁迫对玉米果穗不同位势胚乳干物质积累的影响，选用杂交种‘郑单958’为试验材料，基于盆栽试验设置正常浇水(CK)以及灌浆前期(ED、授粉后第16—25天)、中期(MD、授粉后第26—35天)和后期(LD、授粉后第36—45天)干旱胁迫处理，分析果穗中部(强势位)和顶部(弱势位)胚乳干物质积累动态变化。结果表明:3个灌浆阶段干旱处理不同程度地降低了强、弱势位籽粒胚乳的最大灌浆速率，降低幅度为3.83%~16.75%，缩短灌浆持续期1.17%~13.70%，成熟期粒重、胚乳干重及淀粉含量降低幅度由高到低表现为ED>MD>LD，但蛋白质含量均升高，幅度表现为LD>MD>ED。其中，与CK相比，ED和MD处理强势位籽粒胚乳干重分别降低12.8%和8.7%，弱势位籽粒胚乳干重分别降低23.0%和14.8%；LD处理轻微降低胚乳干重，但未达显著水平。此外，ED对胚乳可溶性糖和淀粉含量影响最大，可溶性糖含量在授粉后20 d显著升高，而淀粉含量在收获期显著降低(强、弱势位胚乳分别降低16.1%和19.4%)；LD对胚乳蛋白质含量影响最大，强、弱势位籽粒胚乳分别比CK提高14.7%和38.0%。综上，籽粒灌浆阶段干旱发生越早，对胚乳干重及粒重抑制越严重；灌浆后期干旱胁迫可以在维持胚乳重量的同时提升蛋白质含量；干旱对弱势位籽粒胚乳物质积累的影响显著大于强势位。 |
| 关键词: 玉米胚乳 灌浆期 干旱 强、弱势籽粒 物质积累 |
| DOI：10.11841/j.issn.1007-4333.2023.05.01 |
| 投稿时间：2022-08-11 |
| 基金项目:国家玉米产业技术体系(CARS-02-16) |
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| Impacts of drought occurred in grain-filling phases on dry matter accumulation of endosperms of superior and inferior maize kernel |
|
CHEN Xianmin1,ZHOU Yaning1,LI Binbin1,XIAO Zudong1,SHEN Si1,2,ZHOU Shunli1,2*
|
| (1.College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China;2.Innovation Center of Agricultural Technology for Lowland Plain of Hebei, Wuqiao 061802, China) |
| Abstract: |
| The aim of this study was to explore the effects of drought occurred at grain-filling stages on maize endosperm from different ear positions. In this study, a hybrid ‘Zhengdan 958' was selected as experimental material. Except normal watering(CK), maize plants were subjected to drought stresses at early stage(ED, 16—25 days after pollination, DAP), middle stage(MD, 26—35 DAP)and late stage(LD, 36—45 DAP)of grain filling under potted plants, respectively. Then, the dynamics of dry matter accumulation in endosperms from the middle(superior position)and apical(inferior position)ears were monitored. The results showed that: The maximum filling rate was reduced by 1. 17% to 13. 70%, and the duration of filling was shortened by 1. 17% to 13. 70% of endosperm from both superior and inferior positions of the ear under drought treatments. Consequently, the grain weight, dry weight and starch content of endosperms at maturity stage were decreased(ED>MD>LD), but the protein content of endosperm was increased(LD>MD>ED). Specifically, under ED and MD treatments, the dry weight of endosperm was reduced by 12. 82% and 8. 74% from the superior position and 23. 0% and 14. 8% from the inferior position compared to CK, respectively. LD slightly decreased the dry weight of endosperm compared with CK without statistical significance. In addition, throughout the whole filling period, ED performed the most profound impact on the contents of soluble sugar and starch, particularly, it promoted the soluble sugar content of endosperm from the superior and inferior positions at 20 DAP, and suppressed starch content of endosperm from both positions by 16. 13% and 19. 42% at harvest, respectively. Whereas, LD performed the greatest effect on protein accumulation, by significantly increasing the protein content in endosperm form the superior and inferior positions by 14. 71% and 38. 01%, respectively. In summary, the endosperm from the inferior position was more vulnerable to drought than those from the superior position. During the grain filling stage, the earlier the drought occurred, the severer reduction in endosperm dry weight and grain weight is. Notably, drought stress at the later phase could promote protein content without yield penalty. |
| Key words: maize endosperm grain-filling stages drought superior/inferior kernel storage accumulation |
