濒危植物秦岭冷杉生殖生态学特征

Study on reproduction ecology of endangered species Abies chensiensis

为了探索秦岭冷杉种群生殖生态学主要特征，通过样地调查、固定样地观测和室内实验分析，系统研究了秦岭地区5个秦岭冷杉（Abies chensiensis）种群生殖特性及其与环境因素的关系，结果表明，5个不同生境的种群都具有结实能力，海拔1500～1600m之间，秦岭冷杉球果的产量较高；各种群球果主要分布在树冠中上部和东、南、西方向；球果以中部产生饱满种子比率最高；秦岭冷杉种子千粒重为43．2g，其中具有生活力者占44．8％，种子的平均含水量为5．7％左右；在天然林散落条件下，种子库的萌发率仅为6．1％，霉坏、搬迁率93．9％；人工播种条件下，种子发芽率在苗圃内高于天然条件下，中低海拔高于高海拔地区。天然条件下，由种子转化成幼苗的过程是秦岭冷杉种群生活史的脆弱环节。秦岭冷杉林经营管理要以就地保护为主，促进种群生殖；要通过森林经营措施，为林下种子萌发和幼苗创造条件；种子脱落后，要及时扰动林下灌木、草本，使种子能够顺利落地，促其发芽成苗；种子大年要注意采种、育苗，扩大人工种群；速生丰产林培育应该以中低海拔的阴坡为主。

Qinling fir, Abies chensiensis ,is endemic to China and was listed in the China Plant Red Data Book as one of the third class conserving plants. It is only found scattered in the forested pockets of the Qinling, Bashan and Shennongjia mountains from 1 300 m to 2200 m ALT in Shaanxi, Gansu, Henan. Sichuan and Hubei provinces. To conserve and restore effectively this species and explore it＇ s processes of reproduction, the production characteristics of cone and seed yields, seed bank dynamics, seed germination rates of 5 Abies chensiensis populations （A, B, C, D, E respectively in Abies chensiensis-Pinus tabulaeformisSinarundinaria nitida-Carex lanceolata association, Abies chensiensis- Quercus aliena var. acutserrata-Litsea pungens-Carex lanceolata association, Abies chensiensis-Betula albo-sinensis-Sinarundinaria nitida-Duchesnea indica association, Abies chensiensis-lndigofera amblyantha- Carex lanceolata association and Abies chensiensis- Pinus tabulaeformis- Smilax stans- Carex lanceolata association） were studied in their natural habitat across 18 plots in the Qinling mountains area. Experiments were carried out in laboratory and field conditions. The results showed the five populations all had potential to produce seeds, and the higher yield occurred in the lower and middle altitude areas every 3-5years. The most cones appeared on the upper and middle foliage of the tree, and the west, south and east aspects of the crown, and the most of full seed appeared on the middle position of the cone. The weight per 1000 seeds was 43.2 g, in which 44.8 % had growing potential. The germination rate of seeds in natural forest was 6.1% and the proportion of seed lost or destroyed in different populations in natural forest was 93.9%. The germination rate of seed that planted in the nursery was higher than that in natural forest, and the germination rate in the lower or middle altitude populations was higher than that in the upper altitude. The course from seed to seedling was the critical period in the life cycling of A. chensiensis populations under natural condition. Reproduction courses were influenced positively by an abundant of tree layer coverage; organic material in the soil, thick soil and a dense population of parent trees, while influenced negatively by human disturbance and light. In situ conservation should be carried out in the future on the A. chensiensis, so as to promote population reproduction. Thinning the shrub layer and grass layer will also help seeds to penetrate the soil, promoting seeds germination. The artificial population should be expanded by collecting seeds in good harvest years. Fast-growing and high-yield plantations should be developed on cloudy slopes at lower or middle altitudes.