弱光照和富营养对苦草生长的影响  

RESPONSES OF VALLISNERIA NATANS TO REDUCED LIGHT AVAILABILITY AND NUTRIENT ENRICHMENT

作　　者：黎慧娟[1] 倪乐意[1] 曹特[1] 朱龙喜 

机构地区：[1]中国科学院水生生物研究所东湖湖泊生态系统试验站,武汉430072 [2]江苏省无锡水文水资源勘测局,无锡214023

出　　处：《水生生物学报》2008年第2期225-230,共6页Acta Hydrobiologica Sinica

基　　金：国家基金面上项目(30570280);“973”项目(2002CB412300)资助

摘　　要：本研究通过比较在不同光照和营养(3光照×3营养)水平下栽培的沉水植物苦草(Vallisneria natansL.)的生长及生化指标,探讨了富营养水体中弱光和高营养对苦草生长的影响。结果表明:弱光对苦草生长的抑制作用不受外源营养浓度的影响;而高营养对苦草生长的影响受到弱光胁迫程度的交互作用,表现为在光照较强的45%日光下为抑制作用,光照最弱的2.5%日光下为促进作用,在光强居间的10%日光下没有明显作用。植物组织总氮、总磷、氨态氮及游离氨基酸氮含量随光照减弱而增加,而可溶性总糖和淀粉含量减少;总磷、氨态氮、游离氨基酸氮及淀粉含量随营养增加而增加。因此弱光照和过高营养均对苦草生长产生明显抑制作用,两者具有交互作用,主要表现为弱光影响了高营养的抑制作用。在本研究中,高营养对苦草生长有抑制作用,但尚不能导致铵中毒或储存碳缺乏;可能由于10%和2.5%日光下,弱光胁迫对苦草的代谢已产生很大抑制作用,限制了高营养对苦草的抑制作用。The effects of light and nutrient availability, 3 （light） × 3 （nutrient）, on growth and N, P and C concentrations of Vallisneria natans were investigated in a microcosm experiment. Growth of V. natans decreased with increased light limitation. Inhibition of increased nutrient loading on the growth of V. natans was observed only in high light treatments, while in medium light treatments there were no significant effects of nutrient enrichment on growth, and the growth of V. natans increased with nutrient enrichment in low light treatments. Low light intensity increased the concentrations of tissue total nitrogen, total phosphorus, ammonia-N and free amino acid-N but lowered tissue soluble sugar and starch concentration. The concentrations of total phosphorus, ammonia-N, free amino acid-N and starch increased with nutrient enrichment. The results indicated that both low light availability and high nutrient availability influenced the growth of V. natans significantly, and that there were interactions between them, showing effects of nutrient enrichment depend on the light availability. Growth inhibition in nutrient enrichments was mainly caused by decreased biomass, but not ammonia toxicity or carbohydrates deficiency. Since the growth of V. natans was severely inhibited by light insufficient in medium and low light treatments, there was no more suppression of nutrient enrichment on growth.

关 键 词：弱光胁迫 营养 苦草 氨态氮 

分 类 号：Q959.11[生物学—动物学]