雌雄异株的大戟科植物中叶片大小和形状的性别差异

雌雄异株的大戟科植物中叶片大小和形状的性别差异作为自然选择的对象，叶片大小和形状能够发挥适应性作用，并且随叶龄而改变。在雌雄异株的植物中，叶片大小和形状因性别而不同，在大多数情况下，雌性的叶片较大。以往研究表明，Adriana tomentosa在叶裂方面存在性别差异。在本研究中，我们探讨了在叶片大小、形状和生理生态等方面是否存在其他性别差异，以及这些差异是否与A. tomentosa的性别适应性和繁殖作用有关。我们测定了生 长在澳大利亚东部的两个不连续种群的雌性和雄性植物的幼叶和老叶的物理化学特征，主要包括：叶面积、周长、锯齿、圆形度、长宽比、圆度以及生态生理指标，包括SLA、干物质质量、叶片水分、RWC、δ ¹³C、δ ¹⁵N同位素比、碳氮含量和碳氮比。同时还测定了叶裂、叶片损伤程度和光合色素含量。在这两个种群中，植物性别显著影响几乎所有与叶片形态相关的参数，如面积、周长、圆形度、长宽比和圆度。与预期相反，我们发现两个种群的雄性具有较大的叶面积且与叶龄无关。雄叶裂片较多，周长较长，但它们较少伸长且锯齿较少。雌性和雄性叶片的生理生态指标差异不大。叶片损伤程度因性别而异，但也因种群而异。叶面积和叶形在性别间的差异不能被生理生态因素所补偿。然而，叶面积可能由其他与叶片形态相关的生理生态机制补偿，因为与雄性相比，雌性的叶面积较小，但叶片锯齿较大。

Intersexual differences in leaf size and shape in dioecious Adriana tomentosa

Aims Leaf size and shape as objects of natural selection can play adaptive roles,and can change with the age of leaves.They can differ between sexes in dioecious species,and in most cases,females have larger leaves.Previous studies showed that sexes of Adriana tomentosa differed in their leaf lobing.In this study,we investigated whether there were other differences between sexes in leaf size,shape and ecophysiology,and if those differences were connected with adaptations and reproductive roles in the sexes of A.tomentosa.Methods Physical and chemical features of young and old leaves originating from female and male A.tomentosa plants growing in two disjunct populations in eastern Australia were measured.We determined leaf area,perimeter length,serration,circularity,aspect ratio(AR),roundness and the ecophysiological factors:specific leaf area,dry matter content,leaf moisture,relative water content,δ¹³C,δ¹⁵N isotope compositions,carbon and nitrogen contents and C:N ratio.Leaf lobing,the degree of lamina damage and the content of photosynthetic pigments were also determined.Important Findings In both populations studied,the sex of plants significantly influenced almost all parameters connected with leaf morphology such as area,perimeter length,circularity,AR and roundness.Contrary to expectations,males from both populations had a greater leaf area that was independent of leaf age.Male leaves were more lobed with a longer perimeter,but they were less elongated and less serrated.Only small differences between female and male leaves were observed for the ecophysiological factors.The degree of leaf damage differed between sexes but also with population.Differences between sexes in leaf area and shape were not compensated by measured ecophysiological factors.However,leaf area may be compensated by other ecophysiological mechanisms related to leaf morphology,because females had greater leaf serration in comparison to males despite the smaller leaf area.