Search Results

You are looking at 1 - 10 of 1,195 items for :

  • "water stress" x
Clear All
Restricted access

Will Wheeler, Reagan Wytsalucy, Brent Black, Grant Cardon and Bruce Bugbee

of water stress ( Tworkoski et al., 2016 ). This was a valuable study, but there are significant challenges in extrapolating from short-term measurements on single leaves to whole plants ( Jones, 2004 ). A common technique in drought-stress container

Free access

Dan Drost

99 POSTER SESSION 15 (Abstr. 685-697) Water Stress and Utilization

Free access

Zhongchun Wang and Gary W. Stutte

Greenhouse grown 2-year-old potted `Jonathan' apple trees (Malus domestica Borkh.) were subjected to various levels of water stress in February. Midday leaf water potential (ψW), leaf osmotic potential (ψS), soluble sugars, and starch contents of mature leaves were measured throughout the development of water stress to determine whether active osmotic adjustment could be detected and whether carbohydrates were involved. Active adjustments of 0.6 MPa were observed 3 and 5 days, respectively, after water stress was initiated. Leaf turgor potential (ψP) could not be maintained through the osmotic adjustment when ψW dropped below -1.6 MPa. Sorbitol, glucose, and fructose concentrations increased while sucrose and starch levels decreased significantly as water stress developed, strongly suggesting that sugar alcohol and monosaccharide are the most important osmotica for adjustment. Sorbitol was a primary carbohydrate in the cell sap and accounted for > 50% of total osmotic adjustment. The partitioning of newly fixed W-labeled photosynthates in mature leaves was not affected by water stress immediately after the 30-min 14CO2 treatment. All the W-labeled carbohydrates decreased in the labeled leaves very rapidly after 14CO2 labeling. The decrease in 14C-sorbitol was greater than the decrease in other carbohydrates under both well-watered and stressed conditions. After 24 hours of water stress, however, the percentage of 14C-sorbitol increased while the percentages of sucrose, starch, glucose, and fructose decreased significantly with increasing levels of stress. The ratio of 14C-sorbitol in leaves with ψW = -3.5 MPa to leaves with ψW = -0.5 MPa was significantly higher than that of 14C-sucrose, 14C-glucose, W-fructose, or 14C-starch.

Free access

Brian Makeredza, Michael Schmeisser, Elmi Lötze and Willem J. Steyn

, 2012 ). Water stress has been reported to exacerbate the development of sunburn ( Barber and Sharpe, 1971 ; Gonda et al., 2006 ), whereas regular irrigation purportedly decreases the incidence of sunburn, supposedly by facilitating sufficient

Free access

Clinton C. Shock, Erik B.G. Feibert and Lamont D. Saunders

76 POSTER SESSION 9 Water Stress, Water Utilization, & Water Management/Cross-Commodity

Free access

A. Naor, I. Klein, H. Hupert, Y. Grinblat, M. Peres and A. Kaufman

The interactions between irrigation and crop level with respect to fruit size distribution and soil and stem water potentials were investigated in a nectarine (Prunus persica (L.) Batsch. `Fairlane') orchard located in a semiarid zone. Irrigation treatments during stage III of fruit growth ranged from 0.62 to 1.29 of potential evapotranspiration (ETp). Fruit were hand thinned to a wide range of fruit levels (200 to 1200 fruit/tree in the 555-tree/ha orchard). Total yield did not increase with increasing irrigation rate above 0.92 ETp in 1996 and maximum yield was found at 1.06 ETp in 1997. Fruit size distribution was shifted towards larger fruit with increasing irrigation level and with decreasing crop level. The two highest irrigation treatments had similar midday stem water potentials. Our findings indicate that highest yields and highest water use efficiency (yield/water consumption) are not always related to minimum water stress. Total yield and large fruit yield were highly and better correlated with midday stem water potential than with soil water potential. This confirms other reports that midday stem water potential is an accurate indicator of tree water stress and may have utility in irrigation scheduling.

Free access

Clinton C. Shock, Erik B.G. Feibert and Lamont D. Saunders

-irrigated onion grown in the Treasure Valley of eastern Oregon should be irrigated at a soil water tension (SWT) of 20 kPa ( Shock et al., 2000a ). Both onion yield and size have also been found to be reduced by temporary imposed water stress. Jones and Johnson

Free access

Craig E. Kallsen, Blake Sanden and Mary Lu Arpaia

, 1970 ; Miller and Turnbull, 1948 ). Other citrus researchers have experimented with periodic water deficits during the growing season. Water stress can affect fruit yield and quality. Summer, fall, and season-long water deficits have increased the

Free access

Sanliang Gu, Sunghee Guak, Leslie H. Fuchigami and Charles H. Shin

145 POSTER SESSION (Abstr. 479–486) Water Stress

Free access

Julián Miralles-Crespo, María J. Sánchez-Blanco, Alejandra Navarro G., Juan J. Martínez-Sánchez, Jose A. Franco L. and Sebastián Bañón A.

et al., 2009 ). In this sense, some authors have suggested that MDS behaves differently in pot-cultivated and soil-cultivated plants under water stress ( Gallardo et al., 2006 ). In gardening and revegetation in Mediterranean areas of Spain, it is