Regulation of the Growth and Activity of Leaf-decomposing Fungi by Dissolved Nutrients (N and P) in Streams

溪流中溶解养分（N 和 P）对叶分解真菌生长和活性的调节

• 批准号: 9207789
• 负责人: Keller Suberkropp
• 金额: $ 6.5万
• 依托单位: University of Alabama Tuscaloosa
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-09-01 至 1994-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9207789&HistoricalAwards=false
• 关键词: Regulation; Growth; Activity; Leaf; decomposing

Fungi have been demonstrated to play key roles in mediating energy flow in the detritus-based food chains in streams. Until recently, however, there have been no methods available that would allow determination of instantaneous growth rates of fungi in any environment. Consequently, quantitative data concerning fungal production or flow of energy through the fungal community are not available. A method for estimating instantaneous growth rates of natural fungal communities by determining rates of incorporation of 14C-acetate into ergosterol was recently described. The proposed studies are designed to adapt and evaluate this method for use on the leaf-decomposing fungal communities in streams. Laboratory studies will establish optimum conditions for the incorporation of acetate into ergosterol and determine factors for converting incorporation rates into growth rates of individual fungal species. Laboratory studies of individual species growing on leaf material will be used to compare estimates of growth rates and production determined by the 14C-acetate method with production estimates determined independently from changes in fungal biomass, respiration and conidium production. The method will then be used to estimate growth rates and production of fungal communities during the decomposition of leaves in two streams that differ in water chemistry. These results will be compared with other measures of activity including total microbial respiration, total microbial biomass and sporulation rates of stream fungi. These studies will contribute to the assessment of a new method that has the potential to make a significant impact on our understanding of fungal activities in the environment and should contribute needed information concerning the productivity of fungi in streams.

真菌已被证明在溪流中以碎屑为基础的食物链中起着调节能量流动的关键作用。然而，直到最近，还没有可用的方法可以测定真菌在任何环境中的瞬时生长速率。因此，关于真菌生产或通过真菌群落的能量流的定量数据是不可用的。最近描述了一种通过测定14c -醋酸酯掺入麦角甾醇的速率来估计天然真菌群落瞬时生长速率的方法。提出的研究旨在适应和评估该方法在溪流中叶片分解真菌群落的应用。实验室研究将确定醋酸酯掺入麦角甾醇的最佳条件，并确定将掺入率转化为单个真菌物种生长速率的因素。对生长在叶片材料上的单个物种的实验室研究将用于比较由14c -乙酸酯法确定的生长速率和产量估计值与独立于真菌生物量、呼吸作用和分生孢子产量变化确定的产量估计值。然后，该方法将用于估计两种水化学不同的溪流中树叶分解过程中真菌群落的生长速度和产量。这些结果将与其他活性指标进行比较，包括微生物呼吸总量、微生物总生物量和溪流真菌的产孢率。这些研究将有助于评估一种新的方法，这种方法有可能对我们对环境中真菌活动的理解产生重大影响，并应提供有关溪流中真菌生产力的所需信息。