濒危植物景宁玉兰的萌条形态特征分析

Analysis on morphological characters of sprouts of the endangered plant Magnolia sinostellata

为了解景宁玉兰萌条发育特点,选择了灌丛(SH)、黄山松林(PTF)、落叶阔叶林(DBF)、杉木林(CLF)和林缘(FE)等5种坡向一致的生境类型,通过样地调查,比较了5种不同生境上景宁玉兰萌条大小、高度及枝系等性状。结果表明:(1)景宁玉兰在黄山松林下的分布密度最高,但5种生境上的景宁玉兰每丛的萌条数量没有差异,每丛最大萌条高度与每丛萌条数没有关系。(2)在落叶阔叶林下的萌枝基径显著小于其他生境(P <0.05),黄山松林下一级枝粗度和长度显著小于其他生境(P<0.05);灌丛中的总分枝率和逐步分枝率最高,灌丛和林缘生境的逐步分枝率(SBR2:3)高于其他生境。(3)在所调查的景宁木兰居群中,大于2根以上萌条的植株达82.5%,说明萌条更新在种群繁衍中发挥着重要作用。本研究表明,景宁玉兰萌生性特征主要受其内在生物学特性所控制,而萌条形态则明显受到所处环境条件的影响。

To understand the properties of sprouts of Magnolia sinostellata species,5 habitat types on the same aspect were selected,including shrubberies(SH),Pinus taiwanensis forest(PTF),deciduous broad-leaved forest(DBF),Cunninghamia lanceolata forest(CLF)and forest edges(FE).The basal diameter,height,and branching patterns of sprouts of M.sinostellata were investigated in the experimental plots at 5 different habitats.The results are as follows.(1)Plant density of M.sinostellata was the highest in P.taiwanensis forest among 5 habitats.There were no differences in sprout number per cluster across 5 habitats.There was no relationship between height of the largest sprout and sprout number per cluster across 5 habitats.(2)Except for sprouts number,the morphological parameters(basal diameter,length,overall bifurcation ratio(OBR),stepwise bifurcation ratio(SBR1-2 and SBR2-3),and length of first-order branch)varied with the different habitats.The basal diameter of sprouts of M.sinostellata growing in deciduous broad-leaved forests was the smallest among 5 habitats.Both basal diameter and length of the first branches of M.sinostellata growing in P.taiwanensis forest were the smallest among 5 habitats.The overall and stepwise bifurcation ratios in shrubberies and the stepwise bifurcation ratios(SBR2-3)at forest edges were the highest among the 5 habitats.(3)In all sites,82.5%of all individuals were composed of more than 2 sprouts,indicating that sprouting played an important role in regeneration of the M.sinostellata population in Lishui.The research indicated that sprouting characters of M.sinostellata were mainly controlled by the inherent biological properties.On the other hand,the morphological characters were markedly influenced by the environment conditions.