珍稀植物蒜头果野生单株结实特性研究

Malania oleifera, an endemic tree, is naturally distributed in karst region of southeast of Yunnan and west of Guangxi Province, China. This plant is a potential species with high economic value as its seed oil contains rich nervonic acid. Much attention has been paid to exploitation and utilization of this species in recent years. Wild fruits of this plant are often collected illegally, and some wild resources are destroyed. Under the premise of protection, rational use is a tendency by artificial cultivation. A better understanding of fruiting characteristics of wild trees can contribute to resource exploitation. We will study the fruiting characteristics of individual trees based on systematic sampling in main distribution area. Some wild individuals are selected and located their position for 2-3 years continuous observation and sampling, and some key environmental factors are investigated around each selected trees . We will observe the number of flowers and fruits in spring and summer, respectively. Fresh fruits from individual trees are collected to measure their weight and size at mature fruit stage in autumn. The content of seed oil and nervonic acid are determined in laboratories. This project aims to: (1) understand the magnitude of change in above main economic characters among individuals; (2) identify the change law of fruiting characteristics and its diversity level in the intra-region and inter-region; (3) analyze the relationship between fruiting characteristics and key environmental factors; (4) reveal the geographical distribution regulation of fruiting characteristics. Malania oleifera is planted with a short history in China, and the cultivation knowledge is lack. Our studies on fruiting characteristics will facilitate the exploitation of wild resources.

蒜头果（Malania oleifera）是我国滇东南与桂西喀斯特山地特有珍稀植物，种仁油富含神经酸，是最为理想开发神经酸的资源植物，具有极其重要的经济开发价值。蒜头果野生资源量十分有限，急需在有效保护的前提下进行开发利用。该项目以蒜头果野生单株为研究对象，通过对整个分布区有代表性单株的系统取样，采用野外观测和实验室分析相结合的方法，查明植株开花结实量、果实与果核的重量和大小、种仁油含量及油中神经酸含量在单株间的变化程度；确定野生单株主要结实性状的变化特征和多样性水平，以及在地域内和地域间的变化规律；通过分析结实特征和主要生境因子之间的关系，了解环境因素对蒜头果结实特性的影响规律，揭示结实特征变化在地理空间上的分布规律。在还未有长期人工栽培历史和栽培经验的情况下，通过野生植株结实特征以及与环境关系的研究分析，为蒜头果的开发利用探明主要经济性状的本底信息，为野生资源的利用奠定基础。

蒜头果（Malania oleifera）是我国滇东南与桂西喀斯特山区特有珍稀植物，种仁油富含神经酸，是最为理想开发神经酸的资源植物，具有极其重要的经济开发价值。以蒜头果野生单株为研究对象，采用野外观测和实验室分析相结合的方法，查明植株开花结实量、果实与果核的重量和大小、种仁油含量及油中神经酸含量在单株间的变化程度，以及在地域内和地域间的变化规律，揭示结实特征变化在地理空间上的分布规律。通过野生植株结实特征研究为野生资源的利用奠定基础。对野生单株四年定点观测，发现小枝开花率大于80%的植株仅占21.3%，小枝开花率小于10%植株占37.5%，总体大部分植株开花较少。即使开花较多植株结果率也较低，平均每株结果实几十至几百个，且有明显的大小年之分，严重大小年植株占83.2%。对广南、富宁、田林、乐业四个蒜头果野生典型分布点的果实特征进行分析，发现果实与果核重量和大小等果实形态特征在单株间有极其显著差异（P<0.001）。这四个种群间广南种群果实和果核都较大，乐业种群果实和果核都较小；种仁油含量富宁种群最高，乐业种群最低，并且都分别与其它3个种群有极显著差异（P<0.01）。种仁油中含11种脂肪酸，主要脂肪酸有神经酸（21.28%～47.24%）、十八碳烯酸（26.35%～49.52%）、二十二碳烯酸（10.94%～17.24%）和二十碳烯酸（1.76%～3.59%），神经酸分别与其它三种主要脂肪酸含量有极显著的负相关关系（P<0.01）。在气候温度较高地区种仁油含量和油中神经酸含量都较高，这说明在较高的气候温度下有利于蒜头果种仁油和神经酸的积累。蒜头果生境中土壤主要养分含量明显较高，叶元素含量与土壤养分含量有显著相关性，植株生长状况也受到土壤细菌影响，表明蒜头果的生长明显受土壤条件影响，进而影响着植株的开花和结实。