that allows for turf survival and post-water stress characteristics as affected by water stress duration and genotype. Although a group of different turfgrasses may experience the same climatic conditions, they may not all experience exactly the same
Kurt Steinke, David R. Chalmers, Richard H. White, Charles H. Fontanier, James C. Thomas, and Benjamin G. Wherley
Julie M. Tarara and Jorge E. Perez Peña
Regulated deficit irrigation is used to manage soil water content to impose predetermined periods of plant water stress or soil water deficit that may elicit a desirable response in the plants (see reviews by Behboudian and Singh, 2001 ; Chaves et
Avinoam Nerd and Park S. Nobel
Water relations and fruit development were studied for up to 100 days after anthesis for potted plants of Opuntia ficus-indica (L.) Mill. (a prickly pear) that were either well-watered or water-stressed, each plant consisting of a medium-sized cladode bearing two or three fruit. Even though cladodes of water-stressed plants lost up to 50% of their thickness, their fruit continued to gain water and to develop; at ripening such fruit had only 16% less water than fruit of watered plants. Maturation indicated by the decrease in fractional peel content and increases in pulp weight and in pulp soluble sugar content was hastened by water stress, leading to ripening ≈88 days after anthesis for water-stressed plants, which was 10 days earlier than for watered plants. Fruit had a lower stomatal frequency than the cladodes but both exhibited Crassulacean acid metabolism behavior. Transpiration occurred mainly at night, and the daily amount of water transpired per unit fruit surface area decreased with time, especially for fruit of water-stressed plants. This decrease was related to fruit expansion (leading to decreased stomatal frequency) for watered plants and to both fruit expansion and water stress for water-stressed plants. At 75 days after anthesis, daily diameter changes of fruit were correlated with transpiration, contraction occurring at night and expansion during the daytime, and changes were greater for watered plants for which daily transpiration was higher.
Yajun Chen, Jingjin Yu, and Bingru Huang
Drought stress is one of the most detrimental abiotic stresses for plant growth. Water deficit in plants leads to stomatal closure and reduces photosynthesis resulting from restricted CO 2 diffusion through leaf stomata (stomatal limitation) and
Bahlebi K. Eiasu, Puffy Soundy, and J. Martin Steyn
Soil water supply is one of the major abiotic factors that determine the biosynthetic processes in plants ( Letchamo et al., 1995 ). Response of essential oil yield and composition to water stress varies with duration and severity of stress
Şemsettin Kulaç, Pascal Nzokou, Deniz Guney, Bert Michael Cregg, and Ibrahim Turna
reduction of water content, increased closure of stomata, and decrease in cell enlargement and growth. Severe water stress may result in the arrest of photosynthesis, progressive suppression of photosynthetic carbon assimilation, disturbance of metabolism
J. Ryan Stewart, Reid D. Landes, Andrew K. Koeser, and Andrea L. Pettay
Environmental stresses such as extremes in soil water availability prevent many attractive woody plants from surviving in managed landscapes ( Kjelgren et al., 2000 ). As such, there is an increasing demand in the nursery industry for aesthetic
Kirk W. Pomper and Patrick J. Breen
Expansion of green-white and red fruit in control (watered) and water-stressed greenhouse-grown strawberry (Fragaria ×ananassa Duch. `Brighton') plants was monitored with pressure transducers. Expansion of green-white fruit in control plants was rapid, showing little diurnal variation; whereas in water-stressed plants, fruit expansion occurred only during dark periods and shrinkage during the day. Red fruit were mature and failed to show net expansion. The apoplastic water potential (ψaw), measured with in situ psychrometers in control plants was always higher in leaves than in green-white fruit. In stressed plants, ψaw of leaves was higher than that of green-white fruit only in the dark, corresponding to the period when these fruit expanded. To determine the ability of fruit to osmotically adjust, fruit were removed from control and water-stressed plants, and hydrated for 12 hours; then, solute potential at full turgor (ψs 100) was measured. Water-stressed green-white fruit showed osmotic adjustment with a ψs 100 that was 0.28 MPa lower than that of control fruit. Mature leaves of water-stressed plants showed a similar level of osmotic adjustment, whereas water stress did not have a significant effect on the ψs 100 of red fruit. Fruit also were severed to permit rapid dehydration, and fruit solute potential (ψs) was plotted against relative water content [RWC = (fresh mass - dry mass ÷ fully turgid mass - dry mass) × 100]. Water-stressed, green-white fruit had a lower ψs for a given RWC than control fruit, further confirming the occurrence of osmotic adjustment in the stressed fruit tissue. The lack of a linear relationship between turgor pressure and RWC prevented the calculation of cell elasticity or volumetric elastic modulus. Osmotic adjustment resulted in about a 2.5-fold increase in glucose and sucrose levels in water-stressed green-white fruit. Although green-white fruit on water-stressed plants showed osmotic adjustment, it was not sufficient to maintain fruit expansion during the day.
Donald J. Garrot Jr., Michael W. Kilby, Delmar D. Fangmeier, Stephen H. Husman, and Andrew E. Ralowicz
1 Extension Plant-Water Relations Specialist. 2 Extension Horticulturist. 3 Professor. 4 Maricopa County Extension Field Crops Agent. 5 Research Associate. Research conducted at Continental, Ariz., in cooperation with Farmers Investment Corporation
Albert Liptay, Peter Sikkema, and William Fonteno
The theme of this review is modulation of extension growth in transplant production through restraint of watering of the seedlings. The purpose of the modulation is to produce transplants of 1) appropriate height for ease of field setting and 2) adequate stress tolerance to withstand outdoor environmental conditions. Physiological responses of the plant are discussed in relation to the degree of water deficit stress and are related to the degree of hardening or stress tolerance development in the transplants. Optimal stress tolerance or techniques for measuring same have not been fully defined in the literature. However, stress tolerance in seedlings is necessary to withstand environmental forces such as wind and sand-blasting after the seedlings are transplanted in the field. It is also imperative that the seedlings undertake a rapid and sustained rate of growth after outdoor transplanting. Water deficit stress applied to plants elicits many different physiological responses. For example, as leaf water potential begins to decrease, leaf enlargement is inhibited before photosynthesis or respiration is affected, with the result of a higher rate of dry matter accumulation per unit leaf area. The cause of the reduced leaf area may be a result of reduced K uptake by the roots with a concomitant reduction in cell expansion. Severe water deficits however, result in overstressed seedlings with stunted growth and poor establishment when transplanted into the field. In transplant production systems, appropriate levels of water deficit stress can be used as a management tool to produce seedlings conducive to the transplanting process.