农杆菌浸种处理对小麦种子萌发及幼苗生长发育的影响

摘要

With the wheat varieties( ' Zheng 9023 ', ' Zhong 13 ', ' Xinong 1376 ' ) as the dominated factors, the concentration,the growth and the infection time of Agrobacteriurn turnefaciens as the deputy factors, the effect of wheat seed germination and seedling physio-biochemical characteristics were studied, using A. turnefaciens-soaking method. The results showed that the interaction effect of varieties and the concentration, the growth, the infection time of A. tumefaciens were not significant; With the A. tume faciens concentration increased,the wheat seed germination rate,the seedling heigh, fresh weight and chlorophyll content were downtrend,and the seedling MDA content,Albinism rate and Kan-resistant seedlings rate were uptrend, and the seedling POD activities were increased at first and then decreased, and the result of the electron microscopy scanning of seedling roots showed that the damage increased. Especially when the concentration more than 1.5 OD,seedlings suffered more significant damage;The growth of A. tumefaciens in 24 h (logarithmic growth phase) was the most active,and the germination rate of seed,the height, the fresh weight and the chlorophyll content of seedling reached the lowest,and the POD activity,the MDA content and the albinism rate were the highest, and the damage of A. tumefaciens was the most;The tendency of the germination rate of seed and the physiology and biochemistry of seedling with the infection time was similar to the concentration,and the seedling growth and development was more obviously inhibited when the infection time increased to more than 1.5 h;The effects of A. tumefaciens were different among wheat varieties. The most appropiate concentration of A. turnefaciens need to be controlled below 1.5 OD,and the growth time of A. tumefaciens may be the 24 h (logarithmic growth phase) and the infection time of agrobacterium tumefaciens should be 1.5 h for reducing wheat stress injury and increasing Kanamycin resistant rate.%以小麦品种(系)'郑9023'、'中13'和'西农1376'为主区,分别以农杆菌菌液浓度、农杆菌生长阶段和农杆菌侵染时间为副区,研究了农杆菌浸种处理后小麦种子萌发及幼苗生理生化特性变化.结果表明,小麦品种(系)分别与农杆菌菌液浓度、农杆菌生长阶段和侵染时间的互作效应不显著;随着农杆菌菌液浓度的增加,小麦种子发芽率、幼苗株高、鲜重、叶绿素含量呈下降趋势,MDA含量、白化苗率、卡那霉素抗性苗率则呈上升趋势,而POD活性则呈先升后降的趋势,小麦种子及幼苗受到的伤害逐渐增大,尤其是农杆菌菌液浓度超过1.5 OD后小麦幼苗受到的伤害更为明显;对数生长阶段的农杆菌活性最高,该阶段处理的小麦种子发芽率、幼苗株高、鲜重、叶绿素含量达到最低,而POD活性、MDA含量、白化苗则达到最大,小麦种子及幼苗受到的伤害也最为明显;随着农杆菌侵染时间的延长,小麦种子萌发及幼苗生长发育的各项指标表现出与农杆菌菌液浓度处理相同的变化趋势,尤其是侵染时间超过1.5 h时,小麦种子萌发及幼苗生长发育受到了显著抑制;各小麦不同品种(系)对农杆菌的反应存在一定基因型差异.研究发现,依据小麦种子萌发及幼苗生理生化特性影响和卡那霉素抗性苗率表现,浸种转化法中的农杆菌菌液浓度应控制在1.5 OD左右,生长阶段宜选用对数生长期,侵染时间以1.5 h较为适宜.