外源植物生长素对鳗草植株促生长作用的研究

Studies on Promotion of Exogenous Auxin to Zostera marina Growth

实验室条件下,研究了5个不同吲哚乙酸(Indole-3-acetic acid,IAA)浓度处理(0(对照)、1、10、50、100μmol·L^(-1))对鳗草(Zostera marina)存活、生长、光合色素含量、过氧化物酶(POD)活力、超氧化物歧化酶(SOD)活力和丙二醛(MDA)含量的影响,分析了外源IAA对鳗草植株的促生长作用。研究显示,经25d培育实验,鳗草地上组织环境海水添加IAA(1~100μmol·L^(-1))显著提高了植株存活率(66%~69%),且植株的单株叶面积、地上组织绝对生长率、地上生产力和总生产力均在100μmol·L^(-1)处理组达到最大值,显著高于其他处理组(P<0.05);鳗草地下组织环境海水添加IAA对植株生长的促进作用不显著,仅50μmol·L^(-1)处理组植株的根长高于对照组植株根长2倍左右;鳗草地上组织环境海水的IAA浓度为100μmol·L^(-1)或地下组织环境海水的IAA浓度为50μmol·L^(-1)时,植株的各光合色素含量达到最大值;IAA对植株POD和SOD活力无显著影响(P>0.05),但高浓度IAA处理条件下植株的MDA含量显著降低。研究结果表明,IAA是一种有效促进鳗草植株生长的生长调节剂,叶片可能是鳗草吸收外源生长素的主要部位,在设定的4个IAA处理中,100μmol·L^(-1)IAA浓度对鳗草植株的促生长作用最显著。

To promote the growth of eelgrass（Zostera marina）,the effects of different concentrations of exogenous auxin（indole-3-acetic acid,IAA;0,the control,1,10,50 and 100μmol·L^（-1））on the survival,growth,photosynthetic pigment content,POD activity,SOD activity and MDA content of eelgrass were examined under laboratory conditions in a period of 25 days.The results showed that IAA（1~100μmol·L^（-1））in seawater covering above-ground tissues significantly increased the survival rate（66%~69%）,nearly two-folds higher than that of the control.The greatest leaf area per shoot,aboveground absolute growth rate,above-ground productivity and total productivity of eelgrass were obtained at 100μmol·L^（-1）,which were significantly higher（P〈0.05）than those attained at other concentrations.No significant difference in survival and growth was observed among different IAA concentrations in seawater covering below-ground tissues;however 50μmol·L^（-1）caused nearly two-folds elongation of roots in comparison with the control.Results also revealed that the two greatest content of photosynthetic pigments was attained at 100μmol·L^（-1）and 50μmol·L^（-1）.MDA content significantly decreased at higher IAA concentrations,but no difference in POD and SOD activities was found.Our findings indicated that exposure to IAA（100μmol·L^（-1））was effective for promoting the growth of Z.marina.