外源L-谷氨酸对花后干旱胁迫下小麦干物质积累分配、籽粒灌浆特性及品质形成的调控效应

李刚; 李超; 王焱栋; 付凯勇; 魏加练; 曾天云; 李诚; 李春艳

doi:10.11674/zwyf.2024001

外源L-谷氨酸对花后干旱胁迫下小麦干物质积累分配、籽粒灌浆特性及品质形成的调控效应

Effects of exogenous L-glutamic acid on dry matter accumulation distribution, grain filling characteristis and quality formation under post-anthesis drought stress in wheat

摘要

摘要:
目的谷氨酸(Glu)具有调节植物生长，提高作物抗逆能力的功效。研究外源 L-谷氨酸（L-Glu）对灌浆期干旱胁迫下小麦干物质积累分配及转运、光合参数、灌浆特性、农艺性状及品质特性的影响，为进一步研究谷氨酸提高小麦耐旱性奠定理论基础。
方法以新疆主栽冬小麦品种新冬18号和新冬22号为试验材料，在抽穗期、开花期分别喷施0、2、4 mmol/L的L-Glu溶液，开花后进行大田干旱胁迫(DT)和适水处理(WT)。在开花初期和花后10、20、30 天 (即灌浆初期、中期、后期)，测定了小麦干物质积累分配及转运、光合特性、灌浆特性、农艺性状及品质等相关指标。
结果外源喷施L-Glu可以显著增加开花后干旱胁迫下地上部总干物质积累量，其中DT-G2、DT-G4处理显著高于DT-G0处理。与DT-G0处理相比，DT-G2和DT-G4处理有效提高了开花后干旱胁迫下干物质积累对籽粒干物质积累的贡献率，新冬18号小麦分别增加24.65%、24.28%，新冬22号小麦分别增加28.44%、16.03%；与DT-G0处理相比，DT-G2、DT-G4处理提高了灌浆期光合速率(P_n)、气孔导度(G_s)、蒸腾速率(T_r)、叶肉瞬时羧化效率(P_n/C_i)及籽粒灌浆平均速率，其中DT-G2、DT-G4处理下新冬18号小麦籽粒灌浆平均速率分别较DT-G0增加15.17%和3.59%，新冬22号小麦分别增加19.92%和14.70%；与DT-G0处理相比，DT-G2处理显著提高了2个小麦品种的千粒重，DT-G4处理显著降低了2个小麦品种的湿面筋含量。
结论抽穗期、开花期喷施外源L-Glu可以显著增加开花后干旱胁迫下小麦地上部总干物质积累量，降低灌浆后期小麦干物质在营养器官的分配比例，同时提高开花后干旱胁迫下旗叶的光合速率及蒸腾速率，进而促进小麦穗部干物质的分配，提高小麦籽粒的灌浆速率，延长灌浆持续时间，最终在降低干旱胁迫下粒重损失的同时提高籽粒品质。

Abstract:
Objectives Glutamic acid (Glu) is capable of regulating plant growth and improving crop stress resistance. The effects of exogenous L-glutamic acid (L-Glu) on dry matter accumulation, distribution and transport, photosynthetic parameters, grain filling characteristics, agronomic and quality characteristics of wheat under drought stress were studied, it provides a theoretical basis for further study on improving drought tolerance of wheat by glutamic acid.
Methods Winter wheat cultivars Xindong18 (XD18) and Xindong22 (XD22) in Xinjiang were used as the field experimental materials. L-Glu solution in concentration of 0, 2 and 4 mmol/L (denoted as G0, G2, and G4, respectively) was sprayed at heading and flowering stages, respectively. Each treatment plot was divided into two parts after flowering stage, one was not watered enough (DT) and the other was watered with adequate amount (WT). The dry matter accumulation in vinous organs at the initial flowering stage and 10, 20, and 30 days after flowering stage (i.e. at early, middle, and late grain-filling stage), the photosynthetic parameters of flag leaves, grain filling characteristics, yield components and grain quality of wheat were determined.
Result Compared with DT-G0, DT-G2 and DT-G4 significantly increased shoot dry matter accumulation (DMA) and the contribution of post-anthesis DMA to grain, the increment rates in XD18 were 24.65% and 24.28%, and in XD22 were 28.44% and 16.03%, respectively. DT-G2 and DT-G4 treatments increased photosynthetic rate (P_n), stomatal conductance (G_s), transpiration rate (T_r), and mesophyll instantaneous carboxylation efficiency (P_n/C_i), elevated the average grain filling rate by 15.17% and 3.59% in XD18 and by 19.92% and 14.70% in XD22. DT-G2 treatment significantly increased the 1000-grain weight, while DT-G4 treatment significantly decreased the wet gluten content of two wheat varieties.
Conclusions Spraying exogenous L-Glu at heading and flowering stages could significantly increase the total dry matter accumulation and the transfer rate of dry matter from shoots to grains at late grain filling stage, and elevate the photosynthetic and transpiration rate of flag leaves under drought stress after anthesis, which is conducive to the distribution of dry matter in ears and high and prolonged grain filling duration, avoid the grain weight loss under drought stress, and form required grain quality finally.

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