异质生境对二型花柱植物雪地报春花性状分化的影响

该研究以生长在新疆北部的二型花柱植物雪地报春(Primula nivalis)为研究材料,对7个低海拔(1 657~2 013m)森林居群和7个高海拔(2 400~2 700m)草原居群的花型比例进行调查,对花部特征进行检测,并对长、短花柱植株在不同海拔居群的花性状分化进行了比较研究,以揭示该类群植物的演化与环境的关系。结果表明:(1)在高海拔草原居群中长花柱植株比例高于短花柱植株。(2)比较草原和森林生态系统中的雪地报春居群,长花柱花形态特征间存在显著差异,但短花柱花形态特征间的差异不显著。(3)高海拔草原居群中长花柱花的花冠筒长度、雄蕊长度、雌雄蕊距离、雌雄异位程度以及雌雄蕊空间位置是导致花性状分化的主要因素。(4)在草原居群中,长花柱花的雄蕊、雌雄异位程度及花冠口至雄蕊距离的变化减少了长短花柱花间的互补式对应性。研究认为,在异质生境中长花柱花性状的变化是导致该物种长短花柱花性状分化的主要因素。     

Pollination adaptations of group-by-group stamen movement in a meadow plant with temporal floral closure

Floral sexual organ (stamen and pistil) movements are selective adaptations that have different functions in male-female reproduction and the evolution of flowering plants. However, the significance of stamen movements in the spatial–temporal function and separation of male and female organs has not been experimentally determined in species exhibiting floral temporal closure. The current study investigated the role of slow stamen (group-by-group) movement in male-female sexual function, and the effect of stamen movement on pollen removal, male-male and male-female interference, and mating patterns of Geranium pratense, a plant with temporal floral closure. This species uses stamen group-by-group movement and therefore anther-stigma spatial–temporal separation. Spatial separation (two whorls of stamen and pistil length) was shown to be stronger than temporal separation. We found that stamen movements to the center of the flower increase pollen removal, and the most common pollinators visited more frequently and for longer durations during the male floral stage than during the female floral stage. Petal movements increased both self-pollen deposition rate and sexual interference in G. pratense. The fruit and seed set of naturally and outcrossed pollinated flowers were more prolific than those of self-pollinated flowers. Group-by-group stamen movement, dehiscence of stamens, pistil movement, and male-female spatial–temporal functional separation of G. pratense before floral temporal closure may prevent male-female and stamen-stamen interference and pollen discounting, and may increase pollen removal and cross-pollination.     

塔里木沙拐枣果实刺毛对果实扩散及萌发的影响

塔里木沙拐枣（Calligonum roborowskii A.Los.）是仅分布于我国西北地区荒漠环境的特有种,其果实为不开裂而周围有椭圆形刺毛的瘦果,以果实为单元进行扩散和萌发。本文采用野外观察与室内控制实验相结合的方法,对塔里木沙拐枣刺毛在果实扩散、吸水、脱水及萌发中的作用进行研究。结果显示：不同贮藏时间的果实颜色、大小、重量及刺毛长度存在显著差异。完整果实在水面漂浮时间及水媒扩散能力比去除刺毛的果实更强。完整果实在1 m/s和4 m/s风速下的扩散距离比无刺毛果实的扩散距离长。10 mmol/L赤霉素（AG₃）及不同干藏时间处理的完整果实与无刺毛果实在20℃/30℃光照和黑暗条件下的萌发率间存在显著差异,其中无刺毛果实的萌发率要高于完整果实的萌发率。室外盆栽实验显示,无刺毛果实的萌发率比完整果实高,说明果实刺毛对果实萌发有抑制作用。研究结果表明果实刺毛对塔里木沙拐枣在塔克拉玛干沙漠边缘荒漠环境中的扩散、萌发及种群更新具有重要的辅助作用。     

Elevation-related variation in the population characteristics of distylous Primula nivalis affects female fitness and inbreeding depression

The population characteristics of distylous species are highly sensitive to stochastic natural selection pressure.Therefore,populations growing under different environmental conditions may vary in floral morph ratios,potentially affecting female fitness and leading to inbreeding depression.However,the variation in offspring quality among populations as a result of inbreeding depression is poorly understood in distylous species.This study investigates variations in plant density,seed mass,seed viabilityfemale fitness,and post-dispersal inbreeding depression in both sexual morphs(long-styled and shortstyled plants)of the distylous Primula nivalis that were subjected to different pollination treatments along an elevational gradient from 1657 to 2704 m a.s.l.Population characteristics(morph plant density and ratio)and fruit set were significantly affected by sexual morph and elevation.Plant density and fruitset frequencies were lower for short-styled than for long-styled plants at 2704 m a.s.l.The seeds from the cross-pollinated flowers of both morphs were higher in quality than those of self-pollinated flowers.The female fitness of seeds from cross-pollinated flowers of both morphs was higher than that of seeds from open-pollinated and self-pollinated flowers.The female fitness of seeds from long-styled flowers was higher than that of seeds from short-styled flowers at all elevations.Inbreeding depression increased with elevation among plants with short-styled flowers but not among those with long-styled flowers.Variation in the elevation-dependent mating system might influence female fitness and affect inbreeding depression in both floral morphs.In conclusion,the low quality of seeds from short-styled flowers at high elevations might decrease short-styled flower frequency,affecting population characteristics.     

新疆郁金香营养生长、个体大小和开花次序对繁殖分配的影响

植物有性繁殖与资源分配的关系研究对于揭示植物生活史特征及繁育系统进化具有重要意义。新疆郁金香(Tulipa sinkiangensis)是新疆天山北坡荒漠带特有的一种多年生早春短命植物。在自然生境中,该物种仅以有性繁殖产生后代,每株能产生1-8朵花,且不同植株上的花数及果实数以及花序不同位置上的花与果实大小明显不同。本文通过对新疆郁金香有性繁殖与营养生长及植株大小的关系以及花序中不同位置花及果实间的资源分配研究,旨在揭示营养生长、个体大小及开花次序对其繁殖分配的影响。结果表明:在开花和果实成熟阶段,新疆郁金香植株分配给营养器官(鳞茎和地上营养器官)与繁殖器官的资源间均存在极显著的负相关关系(P<0.01),说明其植株的营养生长与生殖生长间存在权衡关系。多花是新疆郁金香的一个稳定性状,其植株上花数目、花生物量、果实生物量和种子数量与植株生物量间均呈极显著的正相关关系(P<0.01),说明新疆郁金香植株的繁殖分配存在大小依赖性。在具2-5朵花的新疆郁金香植株中,花序内各花的生物量、花粉数和胚珠数、结实率、果实生物量、结籽数、结籽率及种子百粒重按其开花顺序依次递减,说明花序内各花和果实的资源分配符合资源竞争假说。植株通过减少晚发育的花或果实获得的资源来保障早发育的花或果实获得较多的资源,从而达到繁殖成功。     

基于生态位模型的艾比湖鹅喉羚生境评价

明确物种生境空间分布格局及其与环境因素的关系,对了解该物种的生境需求和适宜生境空间分布至关重要。生境评价和预测是对物种进行有效保护的基础。以鹅喉羚(Gazella subgutturosa)为研究对象,以其重要栖息地新疆博州艾比湖国家级湿地自然保护区为研究区域,选取115个鹅喉羚分布点数据和23个环境变量因子,应用MAXENT模型分析其生境空间分布及主要影响因子,划分了鹅喉羚在研究区域的适宜生境,并对它的栖息地特征进行了分析。探讨了鹅猴羚生境选择与环境因子的关系。结果表明:气温日较差是影响鹅喉羚生境分布的主要环境因子。植被类型,坡度和最干月降水量对艾比湖鹅喉羚的生境选择影响不大。除了温度和降水在内的19项生物气候变量是鹅猴羚选择生境的重要因素之外,海拔和坡向等地形特征也影响鹅猴羚的生境选择性。鹅喉羚的高度适宜生境区主要分布在研究区域的北部和东部,中度及低度适宜生境区则分布于高度适宜生境区的边缘,而非适宜生境区主要集中在西部地区。研究不仅提供了鹅喉羚在艾比湖的实际分布状况及其栖息地特征,也为鹅喉羚在栖息地方面的研究,即鹅猴羚的栖息地选择和环境因子的关系方面提供了一个重要的依据。     

一株蓝麻黄内生真菌XJEG-GF-82的筛选、鉴定及其抑菌活性研究

利用琼脂扩散法从蓝麻黄内生菌中筛选出对农作物致病菌和动物病原菌具有较强抑制活性的内生真菌XJEG-GF-82,其对对玉米小斑病菌、西瓜枯萎病菌的抑菌圈直径分别达18 mm和16 mm,对大肠杆菌、枯草芽孢杆菌、金黄色葡萄球菌的抑菌圈直径分别达19、25、27 mm。根据XJEG-GF-82的形态特征和D1 D2区基因序列特征将XJEG-GF-82最终鉴定为赭曲霉Aspergillus ochraceus。XJEG-GF-82代谢产物中检测出了生物碱和多糖,优化后XJEG-GF-82生成的多糖含量达160.233μg/mL。蓝麻黄内生真菌XJEG-GF-82给新型生物农药及天然药物的研发添加新的微生物资源。     

Morphological plasticity and adaptation level of distylous Primula nivalis in a heterogeneous alpine environment

Plant populations at high elevation face extreme climatic conditions and resource limitations. The existence of distylous species at different elevations can help us investigate their adaptation to high altitudes, the evolution of their morphological characteristics, as well as their responses to limited resources. Here, 17 populations of Primula nivalis at different elevations were evaluated regarding variations in plant morphological characteristics, biomass allocation, and morphological plasticity in a heterogeneous environment. Our results demonstrate that heterogeneous environments can affect plant morphological characteristics and resource allocation in each sexual morph of these plants. Moreover, environmental variations reduced morphological plasticity in the two plant morphs, and the plasticity of long style (LS) plants was greater than that of short style (SS) plants. There were significant negative correlations between morphological characteristics and elevation, rainfall, temperature, and sunshine, and these are the main variables that affect morphological characteristics and resource allocation of both morphs of P. nivalis plants in heterogeneous environments. The morphological characteristics of P. nivalis plants transplanted from high to lower elevations were not significantly different in either population. LS plants had greater morphological plasticity and adaptability in heterogeneous environments than SS plants. Elevational gradients and heterogeneous environments differentiated both morphs of P. nivalis plants with regards to morphology as well as adaptations. LS plants showed a higher level of adaptability than SS plants.