Micrometeorology and physiology of sugarcane crop during water stress

[摘要] Water stress is the single most important factor limiting yieldin plants. The effects of water stress on the micrometeorologyand physiology of sugarcane were investigated using therainshelter facilities provided at the South African SugarAssociation Experiment Station, Mount Edgecombe.Sugarcane variety NCo37 6 was stressed at the age of sevenmonths during the first ratoon crop. Plant extension rate (PER)together with microclimatic measurements including radiationinterception, and leaf and canopy temperature were measuredcontinuously. Photosynthesis and leaf water potential were alsomeasured on a daily basis together with the volumetric soilwater content.Among the yield-determining processes, plant extension rate wasthe first to be significantly affected 10 days after onset ofwater stress. The leaf water potential (ΨL measured at thisstage was -0.7 MPa. Leaf area index and radiation interceptionwere the next processes to be affected. A significant decreasein photosynthetic rate occurred 19 days after onset of waterstress when the ΨLwas at -1.0 MPa. More than 50% reduction inradiation use efficiency occurred 24 days after imposing waterstress and the ΨLmeasured at this stage was -1.5 MPa.Recovery from the first stress as far as plant extension rateand photosynthesis were concerned, occurred within 3 to 4 daysafter irrigation was resumed. When the same sugarcane plantswere stressed for a second time, it took fewer days for plantextension rate and photosynthesis to be severely affected ascompared to the stress imposed during the first time.

[发布机构] University of the Free State