|Author:||Schaller, J. ; Paschold, P. J.|
|Book Group Author:||NA|
Plant water relations, gas exchange parameters and stomata morphology of potted white asparagus (Asparagus officinalis L.) plants were investigated to evaluate the degree of their drought resistance. Two cultivars, 'Gijnlim' and 'Grolim', with high commercial relevance in Germany and with contrasting yield and drought susceptibility were examined. Exclusively the pore length of the kidney-shaped stomata differed but stomata density was similar between the two lines. Stomatal pore length measured on 'Grolim' plants was nearly twice that of 'Gijnlim'. Drought stress was gradually induced by withholding irrigation from one-year old fully developed asparagus plants grown under well-watered conditions in 15 L pots in a greenhouse. During desiccation, predawn water potential of plant (ψPD) and soil (ψsoil), and midday gas exchange of cladophylls were determined. Under well-watered conditions (ψsoil >-8 kPa), plant of 'Grolim' showed higher net assimilation rates (A) and leaf conductance (gH2O) than 'Gijnlim' plants. Intrinsic water use efficiency (WUEint) of unstressed plants did not differ between the cultivars. Only 'Grolim' plants reduced gH2O in response to increased vapour pressure deficit between leaf and air (VPDal), under well-watered conditions. Water shortage rather than VPDal triggered stomatal control. Under severe soil drought conditions (ψsoil <-50 kPa), WUEint of 'Grolim' was higher than that of 'Gijnlim' and gH2O was lower. Under air and soil drought stress, the more sensitive stomatal regulation of 'Grolim' indicates a more efficient protective mechanism against detrimental water loss. These results suggest that 'Gijnlim' employs a strategy of drought tolerance whereas 'Grolim' employs one of drought avoidance. For productivity purposes, water management of 'Grolim' is advantageous due to lower susceptibility to drought stress and higher net photosynthesis under optimal conditions.
|Pages:||145 - 151|
|Journal:||European Journal of Horticultural Science|
assimilation, cultivars, desiccation, drought, droughtresistance, effects, gas exchange, irrigation, leaf conductance,morphology, photosynthesis, plant physiology, plant water relations,productivity, soil, soil water, stomata, stress, susceptibility, useefficiency, vapour pressure, water deficit, water management, waterpotential, water relations, water stress, water use, water useefficiency, Germany, Asparagus, Asparagus officinalis, plants,Liliaceae, Liliales, monocotyledons, angiosperms, Spermatophyta, plants,eukaryotes, Asparagus, Western Europe, Europe, Developed Countries,European Union Countries, OECD Countries, carbon assimilation, carbondioxide fixation, cultivated varieties, drought tolerance, moisturerelations, soil moisture, vapor pressure, water resource management,watering, Plant Production (FF100), Natural Disasters (PP800),Meteorology and Climate (PP500), Environmental Tolerance of Plants(FF900), Plant Water Relations (FF062), Soil Water Management (Irriga