荒漠药用植物黑果枸杞实生苗更新过程的生态学研究

Lycium ruthenicum is a specific medicinal plant in the western desert region of china. Because of the strong slat and drought tolerance, which is also a eocological plant in sand fixation, water and soil conservation and salinization governance. It is widely distributed in the northwest saline desert zone in china and play an important role in ecological environment protection and economic development. In this project, sample plots will be set along envrionment gradient from middle reaches of Heihe river temperate arid zone to lower of Heihe river extreme arid desert area. By field investigation and controlled experiment in the laboratory, methods of population reproductive and physiological ecology were applied to explore systematically ecological process of seedling regeneration. Analysis the ecologically adaptive strategy of Lycium ruthenicum flowering, pollination, and fruiting to desert environment. Seed dispersal space-time dynamics and composion. Seed bank number dynamics and spatial distribution. Seed germination percentage and restrictive factors. Seedling survival and growth dynamics, and its relationship with environmental factors. Aviodance and tolerance mechanisms of Lycium ruthenicum seedling in drought or salt environment. Clarifing the sexual reproduction potential of L. ruthenicum and its relationship with environmental factors. Propose the countermeasures to promote the sexual reproduction of L. ruthenicum population. In order to provide scientific basic for the recovery of L. ruthenicum.

黑果枸杞是我国西部特有的荒漠药用植物，也是防风固沙、水土保持和盐渍化治理的优良生态树种，广泛分布于我国西北荒漠区，对该区域生态环境保护和经济发展发挥着重要作用。当前因野生资源破坏严重，种群数量减少，已被列为重要保护植物。本研究沿环境梯度从黑河流域中游温带干旱亚区至下游荒漠极端干旱亚区设置固定样地，采用样地系统调查、跟踪观测的种群生殖生态方法和室内控制实验，重点研究黑果枸杞种群实生苗更新关键环节的生态学过程，分析黑果枸杞种群开花、传粉、结实对荒漠环境的适应机制；种子散布的时空动态及组成，种子库的数量动态和空间分布；种子成苗机率和限制性因素；幼苗存活、生长动态及其与环境因素的关系；幼苗定居对水分、盐分梯度的适应能力和适应机制，阻碍幼苗正常生长的水分、盐分阈值，阐明黑果枸杞种群有性繁殖潜力及其与环境因素的关系，提出促进黑果枸杞种群有性繁殖潜力的措施，为黑果枸杞种群恢复提供科学依据。

黑果枸杞是我国西北特有的荒漠药用植物，也是防风固沙、水土保持和盐渍化治理的生态树种。本课题通过种群生殖生态学的方法和室内控制实验对黑果枸杞种群实生苗更新关键环节的生态学过程进行了研究，主要研究成果包括：黑果枸杞每个花药具有4个花粉囊，小孢子母细胞减数分裂类型属同时型，雌蕊发育成熟时为中轴胎座；黑果枸杞花期5~10月，单花花期为3d，单株花期持续时间为64d，群体花期为77d，种群开花高峰期持续26d，开花当天黑果枸杞花粉活力最高，达到78.7%，自然条件下花粉寿命约为2~3d。开花前两天黑果枸杞柱头即具有可授性，开花当天至开花后1天内柱头可授性较强，主要传粉媒介为虫媒，黑果枸杞结实主要集中在树冠的上部和中部，下部较少。黑果枸杞平均单果重为0.35g, 单果平均产种数为15.13个。落果高峰期，黑果枸杞种子雨以成熟种子为主。各生境种子雨均表现为成熟种子数＞未成熟种子数＞啃食种子数＞霉烂种子数。黑果枸杞土壤种子库主要分布在距离灌丛50cm范围内。距离灌丛10-20cm的范围内分布最多。20℃黑果枸杞种子的发芽率最高，干旱胁迫不利于黑果枸杞种子的萌发，适度的干旱胁迫有利于黑果枸杞幼苗的生长，但持续胁迫28天后（土壤含水量达到35.33%时），黑果枸杞幼苗叶片开始脱落，地上部分生长缓慢。轻度（0.1mol/L）和中度（0.3mol/L）的盐胁迫有利于黑果枸杞幼苗的生长，但重度（0.5mol/L）的盐胁迫不利于黑果枸杞幼苗的生长。.不同生境均有黑果枸杞实生苗分布，从农田地埂、水渠边、盐化沙地到盐碱荒地实生苗数量显著减少，空气湿度、土壤含水量对黑果枸杞幼苗数量及幼苗生长有显著的影响。在今后的黑果枸杞栽培管理中，幼苗期应加强水分的管理。