Initial exploration of the mechanism underlying H2O2-induced root horizontal bending in pea  

作　　者：Sheng Li Li-Rong Su Shao-Ying Ma Zhen-Zhen Shi Xiao-Ming Yang 

机构地区：[1]Gansu Provincial Key Laboratory of Aridland Crop Science,College of Life Science and Technology, Gansu Agricultural University [2]Institute of Crop, Gansu Academy of Agricultural Sciences

出　　处：《Science Bulletin》2015年第14期1298-1300,共3页科学通报（英文版）

基　　金：supported by the National Natural Science Foundation of China(31160304);Gansu Provincial Key Laboratory of Aridland Crop Science,Gansu Agricultural University,China

摘　　要：It was reported that exogenous hydrogen peroxide （H2O2） can induce primary root bend in Arabidopsis and pea. However, the mechanism remains unclear. Here we explored the mechanism underlying this phenomenon by using the pea （Pisum sativum L.） variety ＂longwan No. 1＂ The results showed that the endogenous indole-3-acetic acid （IAA） content decreased and gibberellin A3 （GA3） content increased in the curving primary pea root induced by H2O2. Meanwhile, both of the two hormones asymmetrically distributed in the inside and outside parts of the curving root. Also, the starch content decreased due to the increased a-amylase activity in this process. However, exogenous Ca2＋ can relieve the horizontal bending of pea root induced by H2O2 and altered the contents of endogenous IAA and GA3. A working model was proposed： Exogenous H2O2 causes the increase in GA3 content, and GA3 stimulates the activity of or-amylase, which leads to the hydrolysis of starch, and then the root lost the gravity perceiving. The asymmetric distribution of IAA and GA3 in two sides of curving root may cause the horizontal bending.Exogenous Ca^2＋ can relieve root bending through altering the endogenous IAA and GA3 contents.It was reported that exogenous hydrogen peroxide(H2O2) can induce primary root bend in Arabidopsis and pea. However, the mechanism remains unclear. Here we explored the mechanism underlying this phenomenon by using the pea(Pisum sativum L.) variety ‘‘longwan No. 1''.The results showed that the endogenous indole-3-acetic acid(IAA) content decreased and gibberellin A3(GA3)content increased in the curving primary pea root induced by H2O2. Meanwhile, both of the two hormones asymmetrically distributed in the inside and outside parts of the curving root. Also, the starch content decreased due to the increased a-amylase activity in this process. However,exogenous Ca2?can relieve the horizontal bending of pea root induced by H2O2 and altered the contents of endogenous IAA and GA3. A working model was proposed:Exogenous H2O2 causes the increase in GA3 content, and GA3 stimulates the activity of a-amylase, which leads to the hydrolysis of starch, and then the root lost the gravityperceiving. The asymmetric distribution of IAA and GA3 in two sides of curving root may cause the horizontal bending.Exogenous Ca2?can relieve root bending through altering the endogenous IAA and GA3 contents.

关 键 词：GRAVITROPISM Exogenous H2O2Horizontal bending Primary pea root 

分 类 号：S643.3[农业科学—蔬菜学] TD528.1[农业科学—园艺学]