Root Carbon Costs and Water Uptake for Desert Succulents

沙漠多肉植物的根碳成本和吸水量

• 批准号: 9002333
• 负责人: Park Nobel
• 金额: $ 23.4万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-09-01 至 1994-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9002333&HistoricalAwards=false
• 关键词: Root; Carbon; Costs; Water; Uptake

One of the last major frontiers in understanding how plants function deals with their roots. The roots benefit a plant by obtaining water and nutrients from the soil and at the same time they impose a cost on the plant, which can most readily be appreciated by considering the carbon incorporated into their structure as well as expended by respiration for their growth and maintenance. Thus, the overall objective of the research is to determine the carbon requirements of water acquisition for the root systems of Agave deserti (an agave native to the southwest of the U.S.), Ferocactus acanthodes (a cactus sympatric with A. deserti), and Opuntia ficus-indica (a cactus that is cultivated worldwide as a vegetable, for cattle fodder, and for its fruits). The responses of the shoots of the three species to environmental conditions have been extensively studied in Dr. Nobel's laboratory over the past 15 years, providing valuable ecological information and also demonstrating that the productivity of O. ficus-indica exceeds that of most conventional agronomic crops. Moreover, the high productivities of such desert succulents are achieved at a very low cost in terms of transpired water, because all three species employ Crassulacean acid metabolism with its nocturnal stomatal opening and a greatly enhanced water-use efficiency. Here, the influences of temperature, soil water status, soil gas phase, and root age on root respiration and water- uptake ability will be determined for individual roots as well as entire root systems for A. deserti, F. acanthodes, and O. ficus-indica. The mechanisms for preventing water loss from the roots to a dry soil will be examined, a feature that is crucial for the survival of perennial plants in deserts. Performing cost/benefit analyses on the roots of these highly successful and productive species will not only provide basic information on how they respond in the natural environment but also can be used to propose new land-use scenarios for the beneficial exploitation of succulent plants under future climatic conditions.

了解植物如何发挥作用的最后一个主要前沿领域之一涉及其根。 根通过从土壤中获取水和养分来使植物受益，同时它们也给植物带来了成本，通过考虑纳入其结构的碳以及生长和维持的呼吸消耗，可以很容易地理解这一成本。 因此，该研究的总体目标是确定龙舌兰（一种原产于美国西南部的龙舌兰）、Ferocactus acanthodes（一种与龙舌兰同域的仙人掌）和仙人掌（一种在世界范围内作为蔬菜、牛饲料及其果实种植的仙人掌）根系获取水的碳需求量。 过去 15 年里，诺贝尔博士的实验室对这三个物种的芽对环境条件的反应进行了广泛的研究，提供了宝贵的生态信息，并证明印度榕的生产力超过了大多数传统农作物。 此外，这种沙漠多肉植物的高生产力是以非常低的蒸腾水成本实现的，因为这三个物种都采用景天酸代谢，其气孔在夜间开放，水分利用效率大大提高。 在此，将确定温度、土壤水分状况、土壤气相和根龄对 A. Deserti、F. acanthodes 和 O. ficus-indica 的单个根以及整个根系的根呼吸和吸水能力的影响。 将研究防止水分从根部流失到干燥土壤的机制，这一特征对于沙漠中多年生植物的生存至关重要。 对这些高度成功和高产物种的根部进行成本/效益分析不仅可以提供有关它们在自然环境中如何反应的基本信息，还可以用于提出新的土地利用方案，以便在未来气候条件下有益地开发多肉植物。