玉米未成熟胚胚性愈伤组织诱导率与内源激素含量的关系

以胚性愈伤组织诱导率高低不同的9个玉米自交系未成熟胚为外植体,用改良N6培养基诱导培养愈伤组织。酶联免疫法测定不同培养时间后未成熟胚,以及由此诱导的胚性和非胚性愈伤组织,内源脱落酸(ABA)、吲哚乙酸(IAA)、赤霉素(GA3、GA4)和细胞分裂素(DHZRI、PA、ZR)含量。结果发现,胚性愈伤组织诱导率与未成熟胚ABA和IAA含量正相关,与胚性和非胚性愈伤组织ABA含量正相关,与胚性愈伤组织GA3含量负相关。在胚性愈伤组织开始发生之际,外植体的ABA和IAA含量出现峰值,GA3含量出现低谷。因此认为,未成熟胚高水平的ABAI、AA含量和低水平的GA3含量,有利于胚性愈伤组织的诱导。但是胚性愈伤组织的ABA含量却低于非胚性愈伤组织,且胚性愈伤组织诱导率与胚性愈伤组织IAA含量负相关。由此看来,胚性愈伤组织的诱导和保持,可能还与各种激素的协同作用有关。

RELATIONSHIPS BETWEEN INDUCTION RATE OF EMBRYONIC CALLUS AND ENDOGENOUS HORMONES CONTENT IN MAIZE

Immature embryos of 9 maize inbred lines with different induction rate of embryonic callus were used as explants and calli were induced and cultured on improved N_6 medium.The methods of enzyme-linked immunosorbant assay were employed to detect endogenous contents of abscisic acid(ABA),indoleacetic acid(IAA),gibberellins(GA_3,GA_4) and cytokinins(DHZR,IPA,ZR) of immature embryos,embryonic and non-embryonic calli during culture process.Positive correlation was found between induction rate of embryonic calli and content of ABA and IAA in immature embryos,between induction rate of embryonic calli and ABA content in embryonic and non-embryonic.Negative correlation was found between induction rate of embryonic calli and GA_3 content of embryonic calli.A peak value of ABA and IAA content and a low value of GA_3 content in explant were detected at the beginning of embryonic calli generation.It was thought that proper high level of ABA and IAA content and low content of GA_3 were benefit to induction of embryonic calli from immature embryos.It was found,however,that ABA content of embryonic calli was lower than non-embryonic calli,and induction rate of embryonic calli was correlated negatively with IAA content of embryonic calli.By this token,induction and subculture of embryonic calli should be related with cooperative effects among different hormones.