On the Relationships between Salinity Tolerance, Growth and Water Use in Citrus
Based on plant growth and leaf chloride (Cl-)concentration in citrus leaves, we tested the hypothesis that salinity tolerance is associated with plant water use. We modified the growth and water use of salinized citrus rootstock seedlings and Valencia trees using elevated CO2 or shade. Growing well nourished seedlings of Cleopatra mandarin (Cleo, relatively salt tolerant) or Carrizo citrange (Carr, relatively salt sensitive) in elevated CO2increased their growth, total leaf area, shoot/root ratio, leaf dry weight per area, and leaf water use efficiency (WUE) but decreased plant water use relative to seedlings grown at ambient CO2. Seedlings of Carr had higher rates of leaf transpiration (Elf) than Cleo. Elevated CO2 decreased leaf Cl- concentration in Carr but not in Cleo leaves. Thus, salinity tolerance was increased by elevated CO2 in the more salt sensitive Carr but not in the more salt tolerance Cleo. Overall, leaf Cl was positively related to Elf but negatively related to plant growth and WUE. Growing two-year-old Valencia orange trees grafted on Carr or Cleo rootstocks under 50％ shade cloth throughout the growing season, increased net gas exchange of leaves but had no effect on tree growth or leaf transpiration (Elf) relative to trees grown in full sunlight. Shade decreased leaf Cl concentrations of salinized trees on Carr but did not affect leaf Cl of trees on Cleo. Leaf Cl was positively correlated with Elf as both were higher in the spring than in the fall regardless of rootstock or shade treatment. Since low leaf Cl - or salinity tolerance was a function of high growth and low water use, an important mechanism of salinity tolerance was the ability to maintain high water use efficiency under salinity stress.
Leaf Cl- Transpiration Water use efficiency
James P. Syvertsen J. C. Melgar Francisco Garcia-Sanchez
UF/IFAS CREC. Lake Alfred, FL 33850, USA CEBAS, CSIC, Campus Universitario de Espinardo, Espinardo, 30100 Murcia, Spain
国际会议
11th International Citrus Congress(第11届国际柑橘大会)
武汉
英文
860-865
2008-10-01（万方平台首次上网日期，不代表论文的发表时间）