Juglans mandshurica is a monoecious heterodichogamous species with protogynous and protandrous mating strategies that occur at a 1:1 ratio and are randomly distributed in the population. The inconsistent male and female flowering periods of the same mating type result in an imbalance of the ratio of male and female flowers, contributing to the low yield of this species. However, little more is known about its floral development. Following three consecutive years of observations, histological analysis, and scanning electron microscopy, we found that the morphological and anatomical development of the male and female flowers were synchronous. The male floral morphological development of J . mandshurica was divided into seven phases, while that of the female flower was nine. Four stages were shared between the male and female flower’s anatomical development. Our findings indicate that there was minimal overlap between sexual functions within the same mating type, guaranteeing synchronization, mutual non-interference, outcrossing, and avoidance of self-fertilization. These results provide a theoretical basis for the improvement of fruit yield and quality through the reasonable allocation of protogynous and protandrous individuals in a population, and for artificial pollination control. Further, these findings lay a foundation for further research on the genetic mechanisms and environmental effects on flower development of heterodichogamous J . mandshurica .

为了掌握胡桃楸(Juglans mandshurica Maxim)不同交配类型开花结实特性及遗传规律,调控其性别分化,增加胡桃楸果实产量,以结实盛期胡桃楸为研究对象,观察了胡桃楸开花物候特征和花粉形态,并采用染色法和培养基法测定了不同贮藏条件下花粉生活力和萌发情况.结果表明:胡桃楸属于雌雄同株异花异熟物种,大多具有2种交配类型,而且这2种交配类型在种群中是随机分布的;雄先型雄花序与展叶同步,雌先型雌花发育与展叶同步,雌先型比雄先型的雌花期早5～8 d,雄花期晚5～6 d.同一类型树木的雌花可授期与雄花散粉期多不一致,雌雄花期先后有序相遇性很差,且十分稳定,雌雄花数量相差也较多.扫描电镜下胡桃楸花粉形态为扁球形,花粉表面有8～16个萌发孔,表面有纹饰;花粉收集之后立即测定,联苯胺法测定的胡桃楸花粉生活力最高,离体培养基法更适合其测定和观察花粉萌发力.4℃条件下更适合胡桃楸花粉贮藏.

为探讨胡桃楸雌雄花芽生理分化过程中各种物质代谢变化规律与花芽分化的关系,以雌先型和雄先型胡桃楸花芽为试材,通过对胡桃楸的物候期的观察和对花芽可溶性糖含量、可溶性蛋白质含量、超氧化物歧化酶(SOD)活性和过氧化物酶(POD)活性变化规律的测定,对其进行生理生化分析.结果表明:胡桃楸雌先型雌花芽、雄先型雌花芽、雄先型雄花芽、雌先型雄花芽的生理分化期分别是3月中下旬～4月下旬、3月末～4月中下旬、4月初～5月初、4月初～5月初,其花期相差10～15d,两种交配类型有2～5d花期相遇的时间完成相互授粉.胡桃楸雌雄花芽在生理分化期芽内物质代谢变化相似,可溶性糖含量变化趋势为:先下降-后上升-再下降,可溶性蛋白质含量与SOD活性变化趋势基本一致,均在生理分化过程中出现低谷,POD活性整体呈上升趋势.不同类型胡桃楸:雌先型胡桃楸雌雄花芽的可溶性糖、可溶性蛋白质含量均明显高于雄先型;雌先型胡桃楸雌雄花芽对可溶性糖和可溶性蛋白质的需求高于雄先型胡桃楸.两种类型的胡桃楸雌雄花芽在SOD活性方面无明显相关性,雌先型雌花芽POD活性高于雄先型雌花芽,两种类型雄花芽中的POD活性相差不多,POD活性与雌花分化联系密切.

To provide the basis for the development,utilization and improved variety selection of Juglans mandshurica,we study on the fruit variant characters and had the type selection by doing distribution investigation,collecting germplasm resources and doing systematic observation of Juglans mandshurica in the eastern liaoning mountain region.Qingyuan,Xinbin,Fushun county,Benxi and Dandong of Eastern Liaoning mountain were comprehensive reconnaissant survied.We selected and divised the fruits of Juglans mandshurica,measured their longitudinal diameter,transverse diameter and lateral diameter,then calculated the average value,relative value and the weight of per fruit.The results showed that fruit germplasm resources of Juglans mandshurica in the eastern liaoning mountain region could be divided into more than ten kinds of fruit shape variation type by phenotypic character,such as spherical,a tip spherical,two tip spherical,a tip oval,two tip oval.Three of these kinds (the spherical,a tip spherical,two tip spherical) of fruit could be used as the playing type and cultivated.This research would be helpful for selecting improved variety ofJuglans mandshurica.