黄瓜果实内源激素与果实空腔的关系

Relationship between endogenous hormones and fruit hollowness in cucumber fruit

【目的】研究黄瓜空腔性状的形成,分析空腔等级与表型性状的相关性,为提高黄瓜果实品质和商品性及黄瓜优质品种的选育提供技术支撑。【方法】以果实空腔性状差异显著的华北型鲜食黄瓜9930和北美加工型黄瓜WI7120为材料,对果实发育进程中的显微结构和内源激素含量的变化进行观察测定。【结果】WI7120果实在授粉后15 d出现明显的空腔性状,为空腔出现的关键时期,至授粉后30 d空腔等级扩大至最高等级。9930果长和WI7120果径的增长呈双S曲线变化,9930果径和WI7120果长的增长呈单S曲线变化。除ABA外,7120果实中激素含量基本上大于9930,且GA>IBA>ZT>ABA。9930果实各部位的GA含量在授粉后15 d内呈下降趋势随后上升,而WI7120则相反。2个品系中除WI7120果实心皮中IBA含量在授粉后15 d后呈下降趋势,其余各部位均呈上升趋势;ZT和ABA含量均在授粉后呈上升趋势。观察石蜡切片发现,WI7120果实心皮细胞在授粉后15 d生长为长圆形,心皮细胞膨大远大于果肉。相关分析发现,WI7120果实的果皮GA和ZT含量与空腔等级呈显著正相关(P<0.05),且果长和果径与空腔等级呈极显著正相关(P<0.01)。【结论】WI7120果实的心皮IBA和GA高于果肉,可能是导致其出现空腔的根本原因。ZT通过促进细胞分裂作用于果实细胞密度来控制果径,进一步影响果实空腔等级。

【Objective】Studying the formation of cucumber hollow traits,analyzing the correlation between hollow grades and phenotypic traits,so as to provide technical support for improving the quality and commerciality of cucumber fruits and the breeding of high-quality cucumber varieties.【Method】The North China fresh cucumber 9930 and the North American processed cucumber WI7120,which were significantly different in fruit hollow traits,were used as materials to observe and determine the changes in the microstructure and endogenous hormone content during the fruit development process.【Result】WI7120 showed obvious hollow character 15 d after pollination,which was the key period for cavity appearance,and the hollow grade increased to the highest level 30 d after pollination.Fruit length of 9930 and fruit diameter of WI7120 increased in a double S curve,fruit diameter of 9930 and fruit diameter of WI7120 increased in a single S curve. Except for ABA,the hormone content in WI7120 fruit was more than 9930,and GA>IBA>ZT>ABA.The GA content in each part of 9930 fruit showed a downward trend within 15 d after pollination and then increased,while that in WI7120 fruit decreased.IBA content in the carpel of WI7120 showed a decreasing trend 15 d after pollination,but the other parts showed an increasing trend. ZT and ABA contents increased after pollination. Observation of paraffin section indicated that the cells in the carpel of WI7120 fruit grew oblong 15 dafter pollination.The cells in the carpel were enlarged much larger than those in the flesh. Correlation analysis showed that the hollow grade of WI7120 fruit was significantly positively correlated with peel GA and ZT contents(P<0.05),and hollow grade had extremely significantpositive correlation with fruit length and diameter(P<0.01).【Conclusion】The IBA and GA in the carpel of WI7120 fruit are higher than that in the flesh,which might be the root cause of the hollowness in WI7120 fruit.By promoting cell division,ZT acts on fruit cell density to control fruit transverse diameter and further affect fruit hollow grade.