光照对沉水植物刺苦草生活史对策的影响

The Effects of Light on the Life-History Strategy of Submerged Macrophyte Vallisneria Spinulosa

以采自江西鄱阳湖的刺苦草冬芽为实验材料,在自然温室中经历了全不遮阳、部分遮阳等4种处理,研究不同遮阳处理产生的光线差异对刺苦草的有性繁殖和无性繁殖方式的资源配制的影响.结果表明,刺苦草的最大叶长、总葡匐茎长和总的叶面积在4种光环境下显著不同(F3,39=10.221,P<0.001;F3,39=12.638,P<0.001;F3,39=73.753,P<0.001).随着遮阳强度的增加,刺苦草的最大叶长、总葡匐茎长和总的叶面积减少,遮蔽强度越大,分配到地下的生物量越多,冠根比率越小;遮阳生境下的刺苦草的有性繁殖受限,无性繁殖形成的分株和冬芽也比自然状态少得多;刺苦草采用回避策略应对光照胁迫.

In order to investigate the effects of different shading levels(Shading levels were: control 0,50%,80%,90%) on the trade-off relations between sexual reproduction and clonal multiplication of Vallisneria spinulosa,a natural greenhouse experiment was carried out by winter tuber of Vallisneria spinulosa being collected from Poyang Lake in the Jiangxi Province.It was found that the longest leaf length,total stolon length and leaf area significantly decreased with the degree of shaded treatments(F3,39=10.221,P<0.001;F3,39=12.638,P<0.001;F3,39=73.753,P<0.001).The more degree shaded treatments were,the more biomass was allocated to the below-ground parts,resulting in the less ratios between above-ground and below-ground biomass.Shaded treatments limited sexual reproductive ability of V.spinulosa,which has reproduced less of ramets and winter tubers under shaded conditions versus natural conditions.V.spinulosa adapted the change of light by means of refuging life-history strategy.