低温胁迫下增施锌肥对水稻氮代谢与干物质积累的影响

刘智蕾; 苏锦铠; 孟静柔; 李鹏飞; 宋佳媚; 张昊楠; 陈志豪; 于彩莲; 袁英才; 彭显龙

doi:10.11674/zwyf.2021288

低温胁迫下增施锌肥对水稻氮代谢与干物质积累的影响

Effect of increasing zinc application on rice nitrogen metabolism and dry matter accumulation under low temperature stress

摘要

摘要:
目的施锌是缓解低温胁迫对水稻伤害的有效途径之一，低温胁迫下研究增加施锌量对水稻氮代谢与物质积累的影响，为低温年提高水稻抗低温能力提供理论依据。
方法采用三叶一心期水稻幼苗进行水培试验，设置低(Zn 0.08 μmol/L)、常规(Zn 0.15 μmol/L)、高(Zn 0.30 μmol/L) 3个ZnSO₄·7H₂O水平，即Zn0.08、Zn0.15、Zn0.30处理。水稻长至五叶一心期时，分别进行低温 (12℃) 与常温 (20℃) 处理，处理7天后取样分析水稻根系活力、抗氧化酶活性、干物质积累、养分吸收与氮代谢等指标。
结果与20℃常温下Zn0.15处理相比，12℃低温下Zn0.15处理水稻丙二醛 (MDA) 含量显著增加，水稻根系总吸收面积、根系活跃吸收面积和根系氧化力降低，水稻地上部氮与锌的积累量减少，导致水稻分蘖数量减少 22.86% (P < 0.05)，地上部及根系干重分别降低 33.60% 和 28.42% (P < 0.05)。12℃低温胁迫下，Zn0.30处理显著提高了水稻根系总吸收面积、活跃吸收面积和根系氧化力，Zn0.08处理水稻根系活力显著下降。12℃低温胁迫下，Zn0.30处理水稻分蘖数量与地上部干重虽然显著高于Zn0.15处理，但仍低于20℃常温下Zn0.15处理。12℃低温胁迫下，Zn0.30处理显著增加水稻含锌量，促进地上部和根系锌的积累，提高硝酸还原酶 (NR) 与谷氨酰胺合成酶 (GS) 活性，显著增加水稻氮积累量，同时提高水稻叶片抗氧化酶活性，使 MDA 含量较Zn0.15处理降低 26.39% (P < 0.05)。在12℃低温下，与Zn0.15处理相比，Zn0.08处理的水稻根系含锌量显著降低，GS活性减少 17.65% (P < 0.05)，根系含氮量降低了4.78% (P < 0.05)。
结论苗期增加施锌量能显著提高水稻根系活力，促进锌吸收，增强氮代谢，减少低温对细胞膜的破坏，促进氮与干物质积累，从而缓解营养生长期低温对水稻的伤害。

Abstract:
Objectives Zinc (Zn) has been proved of enhancing rice growth and resistance to low temperature stress. We studied the potential of increasing Zn supply to alleviate low temperature damage on rice during vegetative period.
Methods A hydroponic culture experiment was conducted using 3-leaves-1-heart leaf rice seedlings inside growth chamber. ZnSO₄·7H₂O concentrations of 0.08, 0.15, and 0.30 μmol/L were set up to represent low, conventional and high Zn application levels. When the rice seedlings grew to 5 leaves-1-heart leaf stage, they were subjected to low and regular temperatures (12℃ and 20℃) for 7 days, then harvested for analysis of dry matter, Zn and N content, root vitality, and indexes of N metabolism.
Results Compared to regular temperature, low temperature significantly reduced the total and active absorption area and oxidizing ability of rice root, decreased N and Zn uptake, and then decreased rice tiller number by 22.86% (P < 0.05), shoot and root dry matter by 33.60% (P < 0.05) and 28.42% (P < 0.05), respectively. Under low temperature, high Zn treatment significantly increased the total and active absorption area, and oxidizing capacity of root, although the rice tillering and shoot dry matter under high Zn treatment were not as high as regular temperature, but were significantly higher than the conventional Zn treatment. Compared with conventional Zn treatment, high Zn under low temperature significantly increased Zn concentration, the nitrate reductase (NR) and glutamine synthetase (GS) activities, the shoot and root N accumulation. Meanwhile, high Zn increased the rice leaf antioxidant enzymes activities and decreased the malondialdehyde concentration by 26.39% (P < 0.05). Under low temperature, rice root Zn concentration decreased significantly, the GS activity and N concentration decreased by 17.65% and 4.78% (P < 0.05), respectively.
Conclusions Increasing Zn supply level during rice seedling stage could increase the root vigor, improve Zn absorption, enhance N metabolism, and then promote nutrients and dry matter accumulation, thus effectively alleviate the possible low temperature damage happened in vegetative stages.

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