高级检索

    云冷杉针阔混交林枫桦种子雨时空分布及种子萌发特性研究

    Spatiotemporal distribution and seed germination characteristics of Betula costata seed rain in the spruce-fir mixed forest

    • 摘要:
        目的  研究东北云冷杉针阔混交林枫桦种子雨时空分布规律和种子萌发状况,为云冷杉针阔混交林物种多样性保护提供理论依据。
        方法  基于在吉林省汪清林业局设立的9块1 hm2固定样地,按对角线五点取样法在每块样地布设5个(9块样地共布设45个)种子收集器收集枫桦种子,采用方差/均值(Cx)、负二项指数(K)、聚集度指标(David和Moore丛生指标,I)、Cassie. R. M.指标(CA)等4种空间分布类型评价方法判别种子雨空间分布状态,此外,从9、10月份收集的种子中,每块样地随机抽取300粒枫桦种子进行种子萌发试验,分别测定种子千粒质量、发芽势和发芽率。
        结果  从7—11月份,共收集到69 100粒种子;枫桦落种高峰期为10月份;种子分布方差/均值(Cx)达1116.30、负二项指数(K)达4.75、聚集度指标(David和Moore丛生指标,I)达1115.30、Cassie. R. M.指标(CA)达0.41,4个指标均显示种子空间分布呈聚集分布;9月份与10月份收集的平均种子千粒质量分别为(0.398 ± 0.064)g和(0.353 ± 0.040)g,9月份种子千粒质量显著高于10月份(P < 0.01);9月份收集的种子平均发芽率为(29.84 ± 11.68)%,显著高于10月份(23.52 ± 8.23)%(P < 0.05)。
        结论  在云冷杉针阔混交林中,枫桦种子小结实量大,且具有明显的时间分布特征,由于在一定程度上种子扩散受到限制,使得枫桦种子呈聚集分布状态。该区域枫桦种源丰富但种子萌发能力差,这些特性将会影响枫桦分布格局,从而影响该地区云冷杉针阔混交林群落结构和物种多样性。

       

      Abstract:
        Objective  The population of Betula costata in spruce-fir mixed forest in northeastern China was taken as the research object. The spatiotemporal distribution of Betula costata seed rain and seed germination characteristics were studied to provide theoretical basis for species diversity protection of the forest.
        Method  Based on the 9 sample plots, 1 ha (100 m × 100 m) each set in Wangqing Forestry Bureau, Jilin Province of northeastern China, sampling by diagonal five points, we set 5 seed traps in each sample plot, totally 45 in 9 sample plots to collect Betula costata seeds. We used 4 evaluation methods on spatial distribution types to distinguish the spatial distribution state of seed rain, including variance-mean ratio (Cx), negative binomial parameter (K), aggregation index (I), Cassie. R.M. index (CA). In addition, 300 Betula costata seeds collected in September and October were randomly selected from each sample plot for seed germination experiment, and the 1 000-grain mass, germination potential and germination percentage were measured, respectively.
        Result  From July to November, 69 100 seeds were collected in total. The peak period of seed falling for Betula costata was October. We found that the seeds of Betula costata presented aggregation distribution at the spatial level based on 4 indexes, i.e. Cx reaching 1 116.30, K reaching 4.75, I reaching 1 115.30, CA reaching 0.41, respectively. The average 1000-grain mass value of Betula costata seeds in September was 0.398 g, which was significantly higher than that in October (0.353 g) (P<0.01). Similarly, the average germination rate in September was (29.84 ± 11.68)%, which was significantly higher than that in October (23.52 ± 8.23)% (P < 0.05).
        Conclusion  In spruce-fir coniferous-broadleaved mixed forest, the seeds are small and fruiting for Betula costata and have obvious time distribution characteristics. Because the diffusion of Betula costata seeds is limited, as a result the seeds show an aggregated distribution pattern. In this region, the characteristics of rich provenance and poor germination ability of Betula costata will affect the distribution pattern of Betula costata, thus affect the community structure and species diversity of spruce-fir coniferous-broadleaved mixed forest in this area.

       

    /

    返回文章
    返回