不同生长环境对红萍生长和生态化学计量特征的影响

Environmental Effects on Growth and Ecological Stoichiometry of Azolla

【目的】研究不同生长环境对红萍生长和生态化学计量特征的影响,可为水生生态系统的生态化学计量学研究提供科学依据,并达到更好地保存红萍种质资源的目的。【方法】设置网室土壤水培养和温室营养液培养2种处理,分析比较两种培养方式条件下,蕨状满江红、墨西哥满江红、卡州满江红、小叶满江红、覆瓦状满江红、羽叶满江红、回交萍、杂交萍等8个红萍品种的生物量,及其C、N、P生态化学计量特征。【结果】8个红萍品种的生物量、C含量与N含量网室土壤水培养处理均高于温室营养液培养处理,P含量则是网室土壤水培养处理低于温室营养液培养处理;红萍的C∶P值与N∶P值网室土壤水培养处理均高于温室营养液培养处理,而C∶N值二者差异较小;由于参试红萍品种的N∶P均较低(仅为1.78～8.08),说明红萍生长主要受N元素的限制。【结论】网室土壤水培养比温室营养液培养更加适合红萍的生长, N元素对红萍的生长和培养至关重要,网室土壤水培养的应该增施氮肥,而温室营养液培养的应该保证营养液中N元素充足。

【Objective】To provide the fundamental scientific information on Azolla for preservation and study the effects of environmental conditions on the growth and ecological stoichiometry of the aquatic plants in the ecosystem.【Method】Using a soil water culture under a net cover(SWN)or a nutrient water culture in a greenhouse(NWG),the biomasses and ecological stoichiometric characteristics on C,N and P of 8 varieties of Azolla,including A.filiculoides lamarck,A.Mexicana Schlecht et cham,A.caroliniana Willd,A.microphylla Kaulf,A.imbricate(Roxb.)Nakais,A.pinnata R.Brown,A.microphylla Kaulf and A.microphylla Minyu No.1,were compared.【Result】In SWN,the biomasses and contents of C and N of all 8 varieties were higher than those in NWG,but the P contents were lower.The C∶P and N∶P ratios of the plants in SWN were higher than those in NWG,whereas,the C∶N ratios were similar.Since the N∶P ratios of all plants grown in either SWN or NMG were below 14,N was presumably the primary factor affecting the plant growth.【Conclusion】Cultivation in SWN appeared to be more conducive than NWG to the growth of Azolla plants.In addition,N seemed to be a crucial nutrient,more so than C or P,for the growth of Azolla.