不同生境广玉兰的花枝性状及开花特性

Floral branch traits and flowering characteristics of Magnolia grandiflora under different habitats

为探明广玉兰的花器官对生境变化的生态适应性表现特征,选取上海师范大学奉贤校区4种生境类型,包括阳生湿地、阳生洼地、阴生平地、半遮荫平地的广玉兰一年生花枝为研究对象,对比了不同生境类型花枝形态性状及生殖分配比、花粉活力、开花物候的特征.主要结果如下:半遮荫平地及阴生平地生境条件下的一年生花枝单叶面积、比叶面积均高于阳生生境;阴生平地的一年生花枝的长度、花直径及宽度相较于其他3种生境,数值更大,呈现出花大叶大,枝条伸展度更高的特征,观赏性极佳.在4种生境中的花干重差异不显著,叶干重和枝干重均存在显著性差异(方差参数F为4.38和3.31,显著性检验指数p<0.05).半遮荫平地生境条件下叶干重极显著高于其他生境(F=4.48,p<0.01),而从花枝各器官干重的分配看,阳生湿地和阴生平地分配给花的有机物质更高,含水率呈现花大于叶、叶大于茎的趋势.阳生湿地生殖分配比极显著高于其余3种生境(F=4.48,p<0.01).不同生境花粉活力存在显著性差异(F=19.00,p<0.01),其中阳生洼地为20.79%,半遮荫平地为7.14%.半遮阴平地生境条件下生长的植株花期开始较早,花期长达46 d,开花早晚与开花持续时间无明显关联.研究结果增进了对植物花器官生态适应性的理解,为广玉兰的栽培和应用观赏方面提供了参考.

To explore the ecological adaptability of annual flowering organs of Magnolia grandiflora L.under different habitats,four habitat types in the Fengxian campus of Shanghai Normal University,including sunny wetland,sunny lowland,shady flatland,and semi-shade flatland,were selected to compare the morphological traits of flowering branches,distribution and reproductive ratio,pollen vigor,and flowering phenology.The main results were:the leaf area and specific leaf area in semi-shade flat and shade flat habitats were higher than those in sunny habitats;the annual branch length,flower diameter and width in the shaded flat were larger than those in the other three habitats,showing larger flowers and leaves and higher branch extension,which were excellent for ornamental purposes.There were not significant differences of flower dry weight among the four habitats,while the significant differences were found in leaf dry weight(F=4.38,p<0.05)and branch dry weight(F=3.31,p<0.05).The leaf dry weight in semi-shade flat habitats was significantly higher than that in other habitats(F=4.48,p<0.01).Comparing the distribution of the average dry weight of flowering branch organs,the organic matter allocated more to flowers in the sunny wetland and shady flatland habitats,and the water content showed a trend of flowers>leaves>stems.The distribution and reproductive ratio in sunny wetland habitats was significantly higher than that in other habitats(F=4.48,p<0.01).Pollen viability differed significantly among the different habitats(F=19.00,p<0.05),with 20.79%in the sunny lowland and 7.14%in the semi-shade flat land.The plants grown in semi-shade flat habitats started flowering earlier and the period was up to 46 days,and there was no significant correlation between the blooming time and the flowering period.The results improved the understanding of the ecological adaptations of plant floral organs,and provided a reference for the cultivation and application of M.grandiflora.