Factors Affecting Root Life-Span in Citrus

9306872统计数据在一系列生态系统中，地下的年生物量生产量大于地上生物量。尽管根的生物量很大，但关于影响根死亡的因素的信息非常少。根碳成本可分为用于根部建设的成本和用于根部维护的成本。维持呼吸可以在短短两到三周内超过生根的总成本，而许多物种的根平均寿命为八个月或更长时间。因此，植物在拥有长寿的根和支付较高的终生维护成本与需要更频繁地建造但终生维护成本较低的较短的根之间进行权衡。我们预测，具有比根长(SRL)高的小直径根的树种可能比比根长(SRL)低的树种具有更高的维持呼吸成本，这可能反过来影响根的寿命。此外，当土壤温度升高导致维持呼吸增加时，根的寿命可能会缩短。在土壤水分、土壤温度和SRL变化的条件下，将在受控实验室的组合中检查盆栽中单个根系和全根系统的根系维持呼吸和根系寿命，以检验这些预测。这项工作对于更好地理解气候变化对全球二氧化碳、可持续农业和植物生长的影响具有重要意义。***

9306872 Eissenstat In a range of ecosystems, there is greater annual biomass productionbelow ground than aboveground. In spite of the magnitude of root biomass production, there is extremely little information on factors influencing root death. Root carbon costs can be divided into that used for root construction and that used for root maintenance. Maintenance respiration can exceed the total cost of root construction in as little as two to three weeks, whereas roots of many species live an average of eight months or longer. Thus, plants experience a tradeoff between having long-lived roots and paying high lifetime maintenance costs vs. shorter lived roots that need to be constructed more often but with lower lifetime maintenance costs. We predict that species with small diameter roots of high specific root length (SRL; root length/mass) may have higher maintenance respiration costs than species of low SRL, which may in turn affect root- life span. Furthermore, when maintenance respiration increases, as caused by increases in soil temperature, root- life span may decrease. Root maintenance respiration and root life-span of individual roots and whole-root systems in pots will be examined to test these prediction in a combination of controlled laboratory under conditions where soil moisture, soil temperature and SRL are varied. This work has important implications for better understanding the effects of climate change on global CO2 sustainable agriculture and plant growth in general. ***