Root Carbon Costs and Water Uptake for Desert Succulents

了解植物功能的最后一个主要前沿领域之一 处理他们的根源。 根通过获得水分而使植物受益 和养分，同时，它们也会增加 植物，这可以最容易地通过考虑 碳结合到它们的结构中， 呼吸来维持其生长和维持。 因此， 研究的目的是确定碳的需求， 沙漠龙舌兰（一种龙舌兰）根系的水分获取 原产于美国西南部），仙人掌（一种仙人掌 与A. Deserti）和仙人掌（仙人掌， 在世界各地种植的蔬菜，牛饲料， 水果）。 三种植物枝条对环境的反应 在诺贝尔博士的实验室里， 过去15年，提供了宝贵的生态信息， 表明O.印度榕树超过了 大多数传统的农业作物。 此外，高生产率 这种沙漠多肉植物是以非常低的成本获得的， 蒸发水，因为所有三个物种采用景天科酸 代谢与夜间气孔开放和大大增强 水利用效率。 在这里，温度，土壤水分 土壤状况、土壤气相和根龄对根系呼吸和水分的影响 吸收能力将被确定为个别根以及 整个根系为A. deserti，F. acanthodes和O.无花果 防止水分从根系流失到干燥土壤的机制 将被检查，这是一个对生存至关重要的功能， 沙漠中的多年生植物。 进行成本/效益分析 这些高度成功和多产的物种的根不仅 提供关于它们在自然环境中如何反应的基本信息， 环境，但也可以用来提出新的土地利用方案， 未来气候条件下多肉植物的有益开发 条件

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.