Corylus trees are monoecious and unisexual plants.The male inflorescences and female buds begin to differentiate in June of the current year and blossom in March next year.The infructescence begin to develop in May and the nut mature in early August in Beijing region.The higher the latitude is,the later the phenophase comes.The light saturation point of photosynthesis of hazel plants is relatively low,and the bimodal peaks are also far away from noon light time,indicating that hazel plant adapts to the shade and weak light conditions.The saline-alkali,low temperature,drought and other stresses conditions may have adverse effect on hazel growth,lead to abnormal physiological indicators,and decrease the photosynthetic capacity.Hazel trees have dichogamous characteristics,different organs have different maturity stage.The required cooling capacity of male inflorescences,female flower buds and leaf buds are 336-1 176 h,504-1 344 h,672-1 512 h,the required calories are 687.0-998.5 GDH ℃,998.5-3 496.1 GDH ℃,and 2 546.5-4 180.3 GDH ℃.Water loss in late winter and early spring is the direct cause of shoot shriveling.The shriveling resistance varieties have high value of the vessel density,total vessel area,vessel/xylem ratio,number of xylem rays and their cross-sectional area,average length of vessel cells and average diameter,and low value of the pore width.The regulatory genes which involve traits such as cold resistance,shoot shriveling resistance,saline-alkali tolerance,inflorescences differentiation and self incompatibility are cloned.The expression and the functions of regulatory genes are analyzed in order to lay a foundation for molecular-assisted selection breeding.The pollen characteristics,stigma receptivity,pollination and fertilization process and the abortion of ovary and ovule were systematically studied in order to provide guidance for improving the pollination effect and preventing blank shell problems.%榛树是雌雄同株异花植物,在北京地区雌雄花序于当年6月开始形态分化,翌年3月开花.坚果发育则从5月下旬开始至8月上旬成熟.纬度越高,物候越晚.榛属植物光合作用的光饱和点较低,双峰型峰值也远离中午强光时段,表明其适应林荫、弱光条件.盐碱、低温、干旱等胁迫条件下榛树生长受到影响,各项生理指标发生改变,光合能力下降.榛树不同器官具有异熟现象,雄花序、雌花芽和叶芽的需冷量分别为336～1 176、504～1 344、672～1 512 h,需热量分别为687.0～998.5、998.5～3 496.1、2 546.5～4 180.3 GDH℃.枝条冬春季失水是导致抽条发生的直接原因,抗抽条品种枝条的导管密度、导管总面积、导管/木质部、射线条数及其横截面积、导管细胞平均长度及平均直径等高而皮孔宽度小.对抗低温、抗抽条、抗盐碱、花芽分化、自交不亲和等主要性状基因进行了克隆、表达与功能初步研究,为分子辅助育种奠定了基础.系统研究了榛属植物花粉特性、柱头可授性、授粉受精过程及子房和胚珠的败育等问题,为提高授粉效果、预防空壳等提供指导.
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