农杆菌共培养条件对小麦种子萌发和幼苗生理生化特性的影响

摘要

With the three wheat varieties (Zheng 9023, Zhong 13, Xinong 1376) as the dominated factors, the cocultivation time,the cocultivation temperature and the AS concentration as the deputy factors,the effect of wheat seed germination and physio-biochemical characteristics of seedling were studied. The results showed that the interaction effects of the wheat varieties and the cocultivation time,the cocultivation temperature and the AS concentration were not significant. With the cocultivation time 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 seeding 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 cocultivation time more than 2 d,seedlings suffered more significant damage. While the cocultivation temperature was 25℃ ,the wheat seed germination rate, the seedling height, fresh weight and chlorophyll content were reached or approached the lowest,and the POD activity,MDA content and albinism rate were the highest,and the negative influence of Agrobacterium tumefaciens was the most; The promotion of damage for wheat seed germination and physio-biochemical characteristics of seedling with the AS concentration of 150 μmol/L was the most. A.tumefaciens effects were different among wheat varieties. The most appropiate A. tumefaciens cocultivation time may be controlled in 2～3 d and the cocultivation temperature was 22～25℃ and the AS concentration was 150μmol/L for reducing wheat stress injury and increasing Kanamhycin resistant rate.%以'郑9023'、'中13'和'西农1376'3个小麦品种(系)为主区,再分别以农杆菌共培养时间、共培养温度以及乙酰丁香酮(AS)浓度为副区,对农杆菌浸种处理后小麦种子萌发及幼苗生理生化特性进行了研究.结果表明,各小麦品种(系)与共培养时间、共培养温度以及AS浓度的互作效应不显著;随共培养时间的延长,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,农杆菌对小麦种子及幼苗的伤害随共培养时间的延长而增大,且当共培养时间超过2 d时其伤害作用更为明显;共培养温度为25℃时,小麦种子发芽率、幼苗株高、鲜重、叶绿素含量达到或接近最低值,POD活性、MDA含量、白化苗率则达到最大值,此时农杆菌对小麦种子及幼苗不利影响最为明显;加入AS能促进农杆菌对小麦的侵染效果,并以150 μmol/L AS的促进作用最强,对小麦种子萌发及幼苗生理生化指标的影响也最大;小麦不同品种(系)对农杆菌的反应存在一定基因型差异.依据共培养条件下小麦种子萌发和幼苗生理生化特性及卡那霉素抗性苗率综合分析认为,农杆菌浸种法转化小麦时较适宜的条件为:共培养时间应控制在2～3 d、共培养温度22～25℃、AS浓度为150 μmol/L.