热激等逆境处理对棉花幼苗根系生长的影响

Study on the Root Growth of Cotton(Gossypium hirsutum) Seedling

采用转基因抗虫棉(DP、BG)、彩色棉(ZH、LV)和普通白色棉(HK)5个棉花(Gossypium hirsutumL.)品种,在光照培养室,研究了棉花幼苗根系生长特性。结果表明:①剪根显著抑制棉花幼苗根系生长,发芽后第2天剪根抑制程度最大,DP、BG对剪根时间敏感,而HK、LV对剪根程度敏感。②适度水分亏缺可刺激棉花幼苗根系生长,HK对水分亏缺十分敏感,其他品种具有一定耐受能力,但耐受机理不同:DP、BG以增加根系长度为主,ZH、LV以增加根系干物质为主。③短时间热激处理显著抑制棉花幼苗根系生长,但抑制程度随热激处理时期、温度、时间不同而异。④激素IAA浸种可促进棉花幼苗根系生长,表现为根面积、长度、干重增加,ZH、DP、LV反应敏感,BG、HK比较钝感,浸种最佳浓度是:4-Cl-IAA和5,6-Cl2-IAA 1mg.kg-1,IAA20mg.kg-1。

The root growth of 5 cotton varieties （DP, BG, ZH, LV, HK） （Gossypium hirsutum L.） was investigated in plant growth chamber with 25℃～28℃ and photoperiod of 12hrs light and 12hrs dark. The result showed that root-tip cutting prohibited significantly the root growth of cotton seedling, and cutting at the second day of germination had the most severe impact. Varieties DP and BG were sensitive to the cutting period, but HK and LV sensitive to the cutting length. Moderate water deficit promoted the root growth. HK was very sensitive to, but the others had a moderate resistance to water deficit. However, the resistant mechanism was different： DP and BG by increasing root length and ZH and LV by increasing dry matter mainly. Short heat shock had a significant inhibiting effect on root growth, which varied from the period treated at, temperature treated on and time treated for. Soaking the seed in IAA solution promoted the root growth with increased root area, length and dry weight. Among the varieties, ZH, DP and LV were more sensitive than BG and HK to IAA. The opti mum concentration of IAA solution was 1mg·kg^-1 for 4-Cl-IAA （1 atom of chloral was added in IAA） and 5,6-CI-IAA （2 atoms of chloral was added in IAA）, and 20mg·kg^-1 for IAA （none chloral atom in IAA）.