不同干旱胁迫下水稻幼苗主根根尖生长的效应

Effects of Different Drought Stress on Root Tip Growth of Taproot of Rice Seedlings

为了探究不同干旱胁迫下水稻幼苗主根根尖生长的效应,本试验利用不同浓度的PEG模拟干旱条件,对根长2 cm的水稻幼苗干旱培养4 d及干旱4 d后复水2 d,通过观察主根根尖导管产生位置和幼苗长势,以及称取主根的重量、测量主根及其根尖的长度,并利用伊文思蓝染色法检测细胞质膜的相对透性。结果表明,随着PEG浓度增加,水稻幼苗主根根尖细胞质膜透性增加,导管产生位置前移,幼苗长势愈差。而复水可缓解干旱胁迫造成的损伤,其中10%和15%PEG的缓解作用比20%和25%PEG的明显。上述结果表明,干旱胁迫导致水稻幼苗主根根尖细胞质膜透性增加和根尖导管产生位置前移,从而导致根尖细胞活力降低和根尖缩短,影响养分和水分的吸收,进而影响根的生长和植株的长势。

In order to explore the effect of root tip growth of taproot of rice seedlings under different drought stress,different concentrations of PEG were used to simulate drought conditions.Rice seedlings with root length of 2 cm were cultured under drought for 4 days,rehydrated for 2 days after drought for 4 days.By observing the differentiation position and seedlings growth of the vessels at the root tips of the taproots,weighing the taproots,measuring the length of the taproots and its root tips,and detecting the relative permeability of the plasma membrane by Evans blue staining.The results showed that with the increase of PEG concentration,the plasma membrane permeability of root tip cells in taproot of rice seedlings increased,the differentiation position of vessel moved forward,and the seedlings growth became worse.Rehydration could alleviate the damage caused by drought stress,and the mitigation effects of 10% and 15% PEG were more obvious than those of 20% and 25% PEG.The above results showed that drought stress led to the increase of plasma membrane permeability of root tip cells in taproot of rice seedlings and the advance of vessel differentiation position in root tip.This leads to the decrease of root tip cell vitality and root tip shortening and affects the absorption of water and nutritions,which will affect the growth of roots and plants.