柑桔种间原生质体融合植株再生及染色体数目变异的研究

为了获得具有抗病、优质丰产等优良性状的柑桔体细胞杂种,本研究应用当前推广良种朋娜脐橙胚性细胞原生质体和抗裂皮病、耐盐碱的红桔叶肉细胞原生质体作为亲本进行体细胞杂交研究。通过对原生质体分离,融合和培养过程中培养基调控等环节的研究,建立起原生质体融合及其后的胚状体再生系统,并从融合处理后的原生质体培养中获得了大最的胚状体,进而获得个别体细胞杂种植株。同时对融合后再生的胚状体染色体数目和同工酶分析,还揭示了在柑桔原生质体融合再生中,胚状体水平上存在淹广泛的遗传变异。其中有14.1%的胚状体为四倍体,近20%为超倍体的非整倍体,并讨论了变异发生及由胚状体再生植株困难的原因。

STUDIES ON CITRUS PLANT REGENERATION AND CHROMOSOMAL VARIATION FOLLOWING INTERSPECIFIC PROTOPLAST FUSION

In order to obtain somatic hybridswith both superior quality and high disea-se resistance,this experiment used Skagg'sBonanza Navel Orange(Citrus sinensisOsb.),which is superior in horticulturaltraits but sensitive to exocortic viroid(CEV)and Dahongpao Red Tangerine(C.reticulata Blanco),which is tolerant toCEV,as the major materials for somatichybridization research.The main resultsobtained were as follows:1.the methodo-logies of citrus protoplast isolation,fusionand culture were systematically investiga-ted and the medium regulation during cul-ture process were stuied in detail,whichled to the establishment'of an effective sys-tem of citrus protoplast fusion and sub-sequent embryoid regeneration.By this sys-tem,the Bonanza navel orange embryoidcotyledon protoplasts were isolated and fu-sed with Red tangerine mesophyll proto-plasts and more than 1000 embryoids andsome plantlets including somatic hybridwere obtained.Based on the experiment,the authors suggested that the citrus pro-toplasts after fusion treatments underwentdirect embryogenensis which was regulatedby the medium statement,and presentedthe detailed technologies improving soma-tic embryogenensis.2.The chromosomenumber variation widely existed in theembryoids derived from the fusion treatedprotoplasts of Bonanza navel orange+Redtangerine,Of them,14.1% of the embry-oids were tetraploids and ca.20% wereaneuploids with 1 or 2 additional chro-mosomes.The results also showed that in-consistency of heterochromatin condesationexisted in some tetraploid embryoids,which inferred that the mitosis of thesomatic hybrids be asynchronous to someextent.This may have some relation withthe difficulties of plant regeneration fromembryoids.