Effect of Polar Auxin Transport on Rice Root Development

生长素极性运输在水稻根发育中的作用(英文)

Polar auxin transport (PAT) is critical in plant growth and development, especially polar differentiation and pattern formation. Lots of studies have been performed in dicots while relative less in monocots. Using two kinds of PAT inhibitors, 2, 3, 5-triiodobenzoic acid (TIBA) and 9-hydroxyfluorene-9-carboxylic acid (HFCA), it was shown that PAT is important for rice (Oryza sativa L. cv. Zhonghua 11) root development, including elongation of the primary roots, initiation and elongation of lateral roots, and formation of adventitious roots. Inhibition of PAT resulted in the shortened primary roots, less and shortened lateral and adventitious roots. Exogenously supplemented NAA can partially rescue the formation of adventitious roots but not lateral roots, while low concentration of NAA (0.1 mumol/L) could not rescue either of them, suggesting the possible different mechanisms of lateral and adventitious root initiations. Treatment of 30 mumol/L TIBA did not completely inhibit the initiation of lateral roots, and survival capacities of which were demonstrated through cross section experiments revealing the presence of primordial of lateral roots at different stages. Further studies through localized application of PAT inhibitors indicated that auxin flow, transported from coleoptiles to the base, is not only responsible for the auxin contents in stem nodes but also critical for initiation and elongation of adventitious roots.

生长素极性运输(PAT)在植物生长发育尤其是极性发育和模式建成中起重要作用。采用2种PAT抑制剂TIBA(2,3,5-triiodobenzoic acid )和HFCA (9-hydroxyfluorene-9-carboxylic acid)处理水稻(Oryza sativa L.cv.Zhonghua)幼苗,结果表明:PAT影响水稻根发育包括主根的伸长、侧根的起始和伸长以及不定根的发育。PAT的抑制导致主根变短、侧根和不定根数目减少。外源附加生长素(NAA)可以部分恢复不定根的形成但不能恢复侧根的形成,表明在侧根和不定根的形成上可能具有不同的机制。切片结果表明,30 mmol/L TIBA处理后并不完全抑制侧根原基的形成,进一步研究表明生长素由胚芽鞘向基部的运输在水稻不定根的起始和伸长中起关键作用。