澳洲坚果多倍体的化学诱导及流式细胞术鉴定

Chemical Induction and Flow Cytometry Identification of Macadamia Polyploidy

以澳洲坚果品种‘云澳57’、‘云澳51’、‘云澳41’和‘云澳58’的萌动种子和幼嫩顶芽为材料,采用浓度为0.1％～0.3％的秋水仙素分别处理48、72（种子）或96 h（顶芽）,对种子的发芽率、幼苗形态和顶芽存活率等进行观测,并对有形态性状变异的植株进行流式细胞术倍性检测.结果表明：随着秋水仙素浓度和浸泡时间的增加,种子的发芽速率减慢,发芽率呈现显著的降低趋势,且不同品种对秋水仙素浓度的敏感性有所差异;大多数处理后种子萌发的幼苗出现了植株矮化、生长缓慢、第一对真叶显著变小或畸形甚至缺失、茎干明显增粗、叶尖出现分叉或卷曲、根系变为须根系等性状,部分幼苗叶片显著增大或分枝显著增多.不同浓度的秋水仙素溶液均可导致澳洲坚果嫁接苗顶芽存活率的降低,但大多顶芽并未出现形态变化.流式细胞术检测发现,在处理后种子萌发的幼苗中出现了多倍体,但均为2C＋4C或2C＋4C＋8C的嵌合体,且多倍体诱变率在5％以下;经秋水仙素处理的嫁接苗顶芽并未检测到倍性变化.

The germinating seeds and young apical bud of macadamia major cultivar ‘YunMac 57’,‘YunMac 51’,‘YunMac 41’and‘YunMac 58’ were immersed by colchicine solution.The solution concentration was 0.1％,0.2％ and 0.3％.The immersing time of germinating seeds was 48 hours and 72 hours,and that of young apical bud was 96 hours.The germination rate and seedling morphology of germinating seeds and survival rate of apical bud were observed.The seedlings with significant morphological variation were identified by flow cytometry.The results showed that the germination of seeds were repressed by colchicines,the sensitivity of colchicine was different between cultivars.Some seedlings showed a series of morphological variations including dwarfed plants,slow growth,smaller or deformed first true leaves,increased stem diameter,biforked or curly leaf opex and fibrous root system.Some seedlings presented very large leaves or more branches.The survival rate of young apical bud was significantly reduced,but most of them had no morphological changes.The chimeric polyploid plants were identified by flow cytometry with 2C＋4C or 2C＋4C＋8C,but the mutation rate was less than 5％ and no polyploidy was identified from colchicines immersed apical bud.