中文摘要：

通过不同蝴蝶花（Irisjaponica）起始源株密度的控制实验,探讨源株对克隆植物蝴蝶花克隆繁殖、生长和生物量分配的影响。结果表明：1）克隆数量特征：1个起始源株处理（O）蝴蝶花新分株数显著高于2个起始源株（T）及4个起始源株处理（F）,而新分株死亡率显著低于后二者;随着起始源株数增加（竞争增强）,一级与二级子株数显著降低。随着源株竞争增强,克隆细根茎与根的长度、表面积、体积与根（茎）长密度逐渐降低。2）叶片特征：随着源株竞争增强,母株重度枯萎与总枯萎叶片数显著增加,子株中度枯萎、重度枯萎与总枯萎叶片数显著增加;源株竞争增强,源株叶面积、源株与子株叶片数显著降低,而源株叶面积比（leafarearatio,LAR）显著增加。3）生物量及分配：随着源株竞争增强,细根茎、粗根茎、克隆繁殖、地上部分、地下部分及总生物量显著降低,细根茎与地下部分分配降低,母株粗根茎分配与地上部分分配显著增加。总的看来,随着蝴蝶花源株竞争增强,植株叶片生长状况受到更大的影响,植株生长受限,克隆繁殖减弱,而其通过增加LAR,提高叶片效率与增加母株粗根茎分配,降低生长强度与消耗,储备资源,以待来年的生长与繁殖。

英文摘要：

Aims Intra-species ortet competition has significant effects on growth,sexual reproduction and clonal propagation of clonal plants.Iris japonica is widely distributed along open area of forest edges and under sparse forest canopies with higher light and water conditions in southern China.It affects other herbs by its dominance through clonal propagation.Our objective was to determine the effect of different initial ortets of I.japonica on clonal propagation and growth.Findings could provide a theoretical foundation for the management of understory vegetation with I.japonica.Methods From September 2007 to June 2008,we conducted a simulation experiment of I.japonica in which we replaced a ortet by an independent one-year ramet.We set up three treatments：one initial separate ortet （O）,two initial separate ortets （T） and four initial separate ortets （F） in 0.7 m × 0.7 m,which represented the effect of intra-species ortet competition.Each treatment had 10 repeats,and we quantitatively measured characters of clonal propagation,leaves and biomass and allocation of clonal propagation in different treatments.Data were analyzed using SPSS software.Important findings The number of new ramets per ortet of I.japonica was higher,and number of dead ramets per ortet was lower in O treatment than in T and F treatments.Number of primary and secondary daughter ramet （per ortet） and length,surface,volume and length per density of fine rhizomes and roots of I.japonica decreased with the increase of initial ortet （ortet competition）.The number of highly withered and total withered leaves of mother ramet,and number of moderately withered,highly withered and total withered leaves of daughter ramet of I.japonica increased with the increase of initial ortet （ortet competition）.Leaf area and number of leaves per ortet and number of leaves for daughter ramet per ortet of I.japonica significantly decreased,and leaf area ratio （LAR） per ortet significantly increased with the increase of initial ortet （ortet co