崔馨月 凌桂芝 肖京林 覃美 唐新莲 黎晓峰

摘 要：为明确生长素与水稻锰毒及抗性的关系，揭示水稻锰毒调控机制，该文采用水培方法研究了锰胁迫对水稻根尖游离生长素含量的影响及外源生长素萘乙酸对水稻幼苗锰吸收、积累和毒害的影响。结果表明：（1）在2 000 μmol·L-1 MnCl2溶液中培养的水稻，根尖游离吲哚乙酸含量显著下降，仅为对照处理的47.7%;水稻根相对伸长率也显著减少，降至对照处理的71.1%。（2）在锰溶液中添加生长素极性运输抑制剂萘基邻氨甲酰苯甲酸（NPA）后，根尖锰含量显著增加，达到了对照处理的1.5倍。（3）在锰溶液中添加萘乙酸后，虽然根尖细胞壁锰含量与对照处理间的差异不显著，但是水稻根相对伸长率显著降低，而植株锰吸收量、根尖锰含量、根尖细胞液中锰的分配比均显著增加;茎基部浸入锰溶液中的离体稻株叶片中的锰含量也在加入萘乙酸后显著提高;在锰胁迫下，添加外源萘乙酸后，水稻根尖OsYSL2、OsYSL6及OsMTP8.1的表达均显著增加。综上结果说明，过量的锰显著抑制水稻根伸长，降低水稻根尖游离态生长素水平，而生长素参与调控水稻对锰的吸收、转运及毒性。

关键词：水稻，生长素，锰，吸收，积累

中图分类号：Q945

文献标识码：A

文章编号：1000-3142（2021）09-1411-06

Abstract：In order to clarify the relationship between auxin and Mn toxicity and resistance of rice，and to reveal the regulatory mechanism of Mn toxicity in rice，the effects of Mn stress on the content of free auxin in root tips of rice and the effects of exogenous auxin NAA on the absorption，accumulation and toxicity of Mn in rice seedlings were studied by hydroponic experiments. The results were as follows：（1）The content of free indoleacetic acid in root tips of rice cultivated in 2 000 μmol·L-1 MnCl2 solution decreased significantly，which was only 47.7% of the control treatment; The relative root elongation was also significantly reduced to 71.1% of the control treatment. （2）The content of Mn in root tips increased significantly after adding the polar auxin transport inhibitor NPA to the Mn solution，which was 1.5 times that of the control treatment. （3）After adding NAA into the Mn solution，the Mn content in root tip cell wall was not significantly different from that of the control treatment，but the relative root elongation was significantly reduced while the absorption amount of Mn in plants，the Mn content in root tips and the distribution ratio of Mn into cell sap of root tips were all significantly increased; The Mn content in the leaves of vitro rice plants immersed in the Mn solution at the stem base was also significantly increased after the addition of NAA; The expressions of OsYSL2，OsYSL6 and OsMTP8.1 in root tips of rice were significantly increased after the addition of NAA under Mn stress. These results indicate that excessive Mn can significantly inhibit root elongation and reduce the level of free auxin in rice root tips. Auxin was involved in the regulation of Mn absorption，transport and toxicity in rice.

Key words：rice，auxin，Mn，absorption，accumulation

錳是植物正常生长发育必需的营养元素。然而，过量的锰会扰乱植物代谢，导致营养失衡、活性氧自由基积累、光合作用受阻，最终抑制植物的正常生长（龙光霞等，2011;吴星等，2015;Huang et al.，2016）。锰毒症状多表现为老叶叶尖和叶缘焦枯，并在叶面上分布大小不一的褐色坏死斑点。……