新疆野核桃濒危机制研究

Juglans cathayensis is an endangered plant species and listed as a class Ⅱ protected species of the national government of China.Based on the accumulation and technology reserve of basic research in conservation biology, we are going to further study the endangered mechanism on J. cathayensis from the own crucial elements of population regeneration to the events of population components suffered in significant damage or death. The main contents include: regulation and rhythmic of flowering phenology population in different altitudes slope position and direction; pollen grains activity; styles capability of been pollinated and ovule abortion rate; morphological study of male and female flower buds development on the time process; proportion study of pollen grains and ovule in male and female flowers ripe in same time and different time respectively; relationship analysis between population seed setting rate and seed yield and environmental factors; Experiments study the causes of multiple trunks grow thickly and multiple clusters formate trunk;contribution analysis for the populations’ survival and development of seedlings and type of vegetative propagation regeneration; situ study of chilling damage and cold damage on population consistents; organs tissue changes in morphology and tolerance physiology study on low temperature treated seedlings; age structure research of heterogeneous habitats population compoents’ pets and disease type and injured extent; spatial distribution and age structure research of population components’ set up dry / wind (snow) down; find out the endangered causes of J. cathayensis,and establish endangered mechanisms model; provide scientific guidance to Xinjiang J. cathayensis protection and management.

新疆野核桃是国家渐危Ⅱ级保护物种，在对其保护生物学基础研究的科学积累和技术储备下，进一步从种群更新的自身关键环节到种群组成遭受重要灾害或死亡事件开展其濒危机制研究。主要研究内容包括：不同海拔坡位、坡向种群开花物候的规律性与节律性及花粉粒活性、花柱可授性与胚珠败育率研究；雌雄花芽发育时间进程的形态结构研究；雌雄花异/同熟繁育系统类型花粉量与胚珠性比的研究；种群结实率与种子产量及其与环境因子的关系分析；多个主干丛生化和主干倒木多个侧枝形成主干的成因试验研究；实生苗和类营养繁殖更新对种群生存与发展的贡献力分析；种群组成冻害和寒害的原位研究；低温处理实生苗的器官组织形态结构变化及耐受性生理实验研究；异质生境种群组成病/虫害类型及受害程度年龄结构研究；种群组成立枯/风(雪)倒的空间分布及年龄结构研究；找出新疆野核桃致危原因，建立新疆野核桃种群濒危机制模型；为新疆野核桃保护和管理提供科学指导。

新疆野核桃是国家Ⅱ级渐危物种，分布范围小，生境破碎化。在其保护生物学研究积累下，从种群更新自身关键环节到种群组成遭受重要灾害或死亡事件开展濒危机制研究。.1.野核桃种群小尺度上呈集群分布，大尺度上呈随机分布，种群斑块大小约25m2。.2.幼苗种群呈增长型结构，1龄幼苗1.7%存活到7龄。.3.幼苗基径、株高在3龄前生长慢（基径1.07~1.46 mm/年，株高4.5~5.7 cm/年），3龄后加快生长（基径2.6~7.9 mm/年，株高8.7~15.9 cm/年）。.4.半阴坡、半阳坡野核桃丛生丛数和丛生株数及分枝成株株数远大于阳坡和阴坡，丛生或分枝成株偏好半阴坡和半阳坡。.5.丛生和分枝成株野核桃种群存活曲线趋于Deevey-Ⅱ型，为增长型结构。种群数量动态受种群生命周期生物学特征影响，具大周期内多谐波迭加的小周期波动特征。.6.丛生和分枝成株野核桃树高、冠幅、枝下高在半阳坡、半阴坡比阳坡、阴坡更具生长优势。坡向与树高、株数与枝下高极显著相关(P<0.01)，株数与树高显著负相关(P<0.05)。.7.死亡野核桃共501株，最大胸径101.9cm，四个坡向死亡野核桃胸径在4龄级最多；最大树高20.0m，阳坡和半阴坡树高5龄级、半阳坡3龄级、阴坡4龄级最多；最大冠幅13.0m，阳坡冠幅3龄级最多，其余2龄级最多；最大枝下高7.0m，枝下高2龄级最多。.8.根系或树干腐烂死亡野核桃129株，病死160株，虫害死100株，三种死亡野核桃胸径3龄级最多，树高5龄级，冠幅和枝下高2龄级。.9.野核桃冻害61.5%，阳坡和半阳坡冻害比例低于阴坡和半阴坡。冻害与冠幅显著相关(P<0.05)，冻害与枝条色泽显著负相关(P<0.05)，冻害与海拔、坡向、胸径、树高、冠幅、生长势均极显著相关(P<0.01)，冻害与枝下高、群落优势种极显著负相关(P<0.01)。.10.野核桃患褐斑病95.16%，枯枝病89.76%，黑斑病74.11%，腐朽病7.68%。.11.风雪倒折野核桃561株，阴坡和半阴坡风雪倒折野核桃多于阳坡和半阳坡。.12.风雪倒折野核桃胸径9.5~98.7cm，树高3.8~18.8m，冠幅2.3~18.0m，枝下高0.2~7.0m，折断处高度0.0~9.5m。折断处高度与坡向、胸径、树高、冠幅、枝下高极显著相关(P<0.01)。