Authors:T. Y. Reddy, V. R. Reddy, and V. Anbumozhi
.) in subtropical Australia. 3. Growth and water use during a terminal droughtstress. Australian J. Exp. Agric. , 32 , 197-203.
Plant population studies on peanut (Arachis hypogaea L.) in subtropical Australia. 3. Growth and
suitable for various cropping systems. However, this crop is susceptible to droughtstress, especially during the reproductive phase ( Ranawake et al., 2011 ; Sadeghipour, 2009 ).
Drought is a major environmental factor that limits crops growth and
Authors:K. Pouri, A. Sio-Se Mardeh, Y. Sohrabi, and A. Soltani
Water deficit is a most limiting factor for wheat in rain-fed agricultural systems worldwide. The effects of drought stress on some root features and yield and yield components in wheat (Trticum aestivum L.) were carried out in a factorial experiment based on completely randomized design, under greenhouse condition. The four experimental irrigation regimes, irrigation after 75% of the water was depleted (control), irrigation after 65% of the water was depleted (mild stress), irrigation after 55% of the water was depleted (moderate stress) and irrigation after 45% of the water was depleted (severe stress) were randomized for the main plots. The subplot treatments included eight wheat genotypes. Results showed that Interaction Drought stress with Variety had significantly affected on Total Root Volume and Dry Matter, Number of Tiller and also Shoot Dry Matter. Value of Total Root Volume and Dry Matter, Shoot Dry Matter and Number of Tiller in irrigated varieties were more than rainfed in whole of Drought stresses. N-87-20 variety had most amounts of Total Root Dry Matter, Total Root Volume (exception of control) in all of stresses and control. Root properties influence on yield and other morphological traits of wheat. Stress intensification increase root growth than plant organ so that wheat root can uptake water from soil to compensate damage caused by stress.
Authors:M. Safar-Noori, D.V.M. Assaha, and H. Saneoka
Drought stress severely reduces wheat productivity and affects grain quality. In this study the effects of combined application of salicylic acid (SA) and potassium (K) on yield and grain quality of wheat under drought stress condition was investigated. Winter wheat cultivar Minaminokaori was grown in pots in a greenhouse, and subjected to 3 levels of K (50, 100 and 200 kg ha–1) fertilizer applications. The plants were foliar sprayed with SA (0.7 mM) at heading stage, and then imposed to the drought stress until grain maturity. Drought stress decreased grain yield by 41.1%, starch content by 10.2% and water-soluble pentosan content by 3.5% in comparison to well-irrigated control. However, grain crude protein content, total pentosan content and phytate phosphorus content were increased by 33.0%, 17.9%, and 13.4% respectively. Under the same drought condition, the application of combined SA and high K levels has increased grain yield (13.3%), starch (12.2%) and water-soluble pentosan content (20.3%) compared to SA-untreated with low level of K fertilizer. In addition, SA application decreased the percentage of phytate phosphorus to total phosphorus under drought stress. These results suggested that combined treatment of SA foliar application and a higher doses of K fertilizer can partially improve wheat productivity, grain nutritional quality, particularly water-soluble pentosan that influences the bread-making quality, without increasing the anti-nutrient component phytate under drought stress condition.
The stress reaction of maize plants was evaluated in relation to drought stress intensity and to growth stages by assessing the transpiration intensity and the expression of two dehydrin genes, DHN1 and DHN2. The maize plants were grown under four different watering conditions: well-watered (control), mild stress, moderate stress and high stress. The sap flow values were taken as an indicator of plant stress reactions at the transpiration level. A significant correlation between the average diurnal values of sap flow and the volumetric soil moisture appeared only for the moderate stress condition (R = 0.528) and for the high stress condition (R = 0.395). Significant increases in the expression of DHN1 and DHN2 (DHN1 = 105-fold and DHN2 = 103-fold) were observed primarily for the high stress condition compared to the control. Differences in the stress reactions at the DHN1 gene expression level were detected for all the experimental drought stress conditions. A relatively close relationship between the levels of expression of both genes and the values of the sap flow was observed during the initial stage of the stress (R = –0.895; R = –0.893). The severity of water stress and transpiration intensity significantly affected certain biometric and yield parameters of maize. Higher DHN genes expression at the ripening stage was related to lower grain and dry biomass yield. The results indicated that DHN gene expression assessment in maize and evaluation of the changes in transpiration expressed by the sap flow could be considered appropriate indicators of stress intensity while the DHN gene expression assessment appeared to be more sensitive than evaluation of the changes in transpiration, mainly in the initial phases of stress response.