黄腐酸对水稻幼苗根系生长的影响及其与生长素的关系

Effect of Fulvic Acid on Root Growth of Rice Seedlings and Its Relationship with Auxin

该研究以水稻品种‘宁粳6号’为材料,通过外源使用黄腐酸(FA)与生长素抑制剂共同处理水稻,探究FA对水稻根系生长的影响及其与生长素之间的关系。结果表明:(1)50~800 mg·L^(-1) FA处理水稻幼苗6 d后,当FA浓度超过100 mg·L^(-1)时显著促进水稻种子根的伸长生长;FA浓度超过400 mg·L^(-1)时,与对照组相比水稻的平均侧根长和侧根密度显著增加。(2)与对照相比,低浓度FA处理对水稻幼苗根尖生长素的含量无显著影响,但400 mg·L^(-1) FA处理后显著提高了内源生长素的含量。(3)3μmol·L^(-1)生长素合成抑制剂4-联苯硼酸(BBo)、4-苯氧基苯基硼酸(PPBo)或30μmol·L^(-1)生长素信号转导抑制剂2-(对-氯苯氧)-异丁酸(PCIB)处理均可显著抑制水稻根和侧根的发生;1μmol·L^(-1)生长素极性运输抑制剂三碘苯甲酸(TIBA)可显著抑制水稻种子根的伸长生长与侧根发生,但对侧根长度无显著作用。(4)FA与BBo或PPBo共同处理可显著抑制FA对水稻根系伸长生长与侧根发生的促进作用;TIBA和PCIB分别和FA共同处理水稻,可显著抑制FA对种子根伸长生长的促进作用,且PCIB可显著抑制FA对侧根发生的促进作用,但TIBA对此没有显著影响。研究发现,外源FA可能通过调控植物内源生长素的合成、极性运输或信号转导来调控水稻根的伸长生长和侧根的发育。

In this study,we used‘Ningjing No.6’as the material,treated with exogenous fulvic acid(FA)and auxin inhibitors to explore the effect of FA on root growth and its relationship with auxin.The results showed that:(1)after treatment of rice seedlings with 50~800 mg·L^(-1) FA for 6 days,when the concentration of FA exceeded 100 mg·L^(-1),the root elongation was significantly promoted;when the concentration of FA exceeded 400 mg·L^(-1),the average lateral root length and lateral root density of rice in FA treatment group increased significantly compared with the control.(2)Compared with the control,low-concentration FA treatment had no significant effect on the content of auxin in the root tips of rice seedlings,but 400 mg·L^(-1) FA treatment significantly increased the content of endogenous auxin in the root tip of rice seedlings.(3)3μmol·L^(-1) auxin synthesis inhibitor 4-biphenylboronic acid(BBo),4-phenoxyphenylboronic acid(PPBo)or 30μmol·L^(-1) auxin signal transduction inhibitor p-chlorophenoxy isobutyric acid(PCIB)treatment significantly inhibited the growth of rice roots and the occurrence of lateral roots;1μmol·L^(-1) auxin polar transport inhibitor triodobenzoic acid(TIBA)treatment significantly inhibited the elongation and growth of rice roots and the occurrence of lateral roots,but has no significant effect on the lateral root length.(4)The co-treatment of FA with BBo or PPBo could significantly inhibit the promotion of FA on rice root elongation and lateral root formation.TIBA and PCIB treated rice together with FA could inhibit the promotion of FA on the growth of roots.In addition,PCIB could repress the promotion of FA on lateral root development,but TIBA has no significant effect.These results indicate that exogenous FA may regulate root elongation and the development of lateral roots by regulating the synthesis,polar transport or signal transduction of endogenous auxin.