Stress drought

Knorr, W. and Heimann, M. (1995). Impact of drought stress and other factors on seasonal land biosphere CO2 exchange studied through an atmospheric tracer transport model, Tellus, Ser. B, 47, 471-489. 

Kramer, P.J. (1980). Drought stress and adaptation. In Adaptation of Plants to Water and High Temperature Stress, ed. N.C. Turner P.J. Kramer, pp. 6-20. New York Wiley. 

Boot, R., Raynal, D.J. Grime, J.P. (1986). A comparative study of the influence of drought stress on flowering in Urtica dioica and U. urens. Journal of Ecology, 74, 485-95. 

Herrero, M.P. Johnson, R.R. (1981). Drought stress and its effect on maize reproductive systems. Crop Science, 21, 105-10. 

An intriguing stress-induced alteration in gene expression occurs in a succulent plant, Mesembryanthemum crystallinum, which switches its primary photosynthetic CO2 fixation pathway from C3 type to CAM (Crassulacean acid metabolism) type upon salt or drought stress (Winter, 1974 Chapter 8). Ostrem et al. (1987) have shown that the pathway switching involves an increase in the level of mRNA encoding phosphoenol-pyruvate carboxylase, a key enzyme in CAM photosynthesis. 

The major physiological attributes that support net carbon gain under conditions of drought stress can be approached by two well-known and simple relationships. The first is that of de Wit (1958),... 

Therefore drought resistance (in terms of plant production) is positively associated with T or Ea, m or WUE and HI under drought stress. A simple simulation using (1) would indicate that a given increase in Tor m is most effective towards plant production when water stress is not severe. 

Surprisingly, very little physiological work has been done to understand the nature and processes of plant recovery from extreme drought stress, especially in relation to plant production (Chapter 7). In order for the plant to recover properly from severe water stress, its various meristems must survive. The association between severe plant stress and the factors that affect meristem survival and function upon rehydration are unclear though osmoregulation may have a possible protective role and as a potential source of carbon for recovery. Active plant apices generally excel in osmoregulation and do not lose much water upon plant dehydration (Barlow, Munns Brady, 1980). 

Blum, A., Mayer, J. Golan, G. (1983a). Chemical desiccation of wheat plants asa simulator of post-anthesis stress. II. Relations to drought stress. Field Crops Research, 6, 149-55. 

Rumbaugh, M.D., Asay, K.H. Johnson, D.A. (1984). Influence of drought stress on genetic variances of alfalfa and wheatgrass seedlings. Crop Science, 24, 297-302. 

Drought stress increases the soil mechanical impedance on plant roots, which in turn can stimulate root exudation (1,4,5). lncrea.sed release of mucilage may contribute to the maintainance of Zn uptake in dry soils by facilitating Zn transport to the root surface in mucilage-embedded soil particles (264). This effect might be supported by water transfer from the subsoil in the roots, which is... 

Topsoil should have a loose and open structure so that it drains fast to keep the ground surface dry. At the same time, it must be able to retain enough moisture in order that plants growing in it are not constantly subjected to drought stress. The properties of interest include particle gradation, clay content, nutrient content, and retention capacity. 

Wotton, H.R. and Strange, R.N. (1987). Increased susceptibility and reduced phytoalexin accumulation in drought-stressed peanut kernels challenged with Aspergillus flavus , Applied and Environmental Microbiology, 53, 270-273. 

Gawronska, H., and Grzelak, K., 1993, Seed germination and seedling vigoumr of triticale ( X Triticosecale Wittmack) under drought stress. Plant Varieties and seeds 6 9-19. 

During drought stress, ABA regulates stomatal closure, whereas increased ethylene production has an inhibitory influence on ABA action. An inhibition of ethylene synthesis delays drought-associated chlorophyll loss, supporting the role of ethylene in drought-induced senescence. °°... 

When subjected to drought stress, excised wheat Triticum aestivum L.) leaves increase ethylene production as a result of an increased synthesis of ACC 71 and an increased activity of the ethylene-forming enzyme (EFE) which catalyzes the conversion of ACC 71 to ethylene. Rehydratation to relieve water stress reduces EFE activity to levels similar to those in non-stressed tissue. Pretreatment of the leaves with N-benzyladenine (BA) 75 or indole-3-acetic acid lAA 76 prior to drought stress caused further increase in ethylene production. Conversely, pretreatment of wheat leaves with abscisic acid ABA 77 reduced ethylene production to levels of non-stressed leaves, accompanied by a decrease in ACC 71 content, Eq. (29). 

In addition to the induction of anthocyanin biosynthesis, chilling stress has also been shown to promote the formation of colorless flavonoids. Cold treatments (and drought stress) caused increases in levels of (—)-epicatechin and hyperoside (quercetin 3-galactoside) in two species of hawthorn, Crataegus laevigata and C. monogyna. Such treatments also enhanced the antioxidant capacity of the shoot extracts, and this may be the primary function of these cold-inducible flavonoids. 

Riera M, Yalon C, Fenzi F, Giraudat J, leung J. 2005. The genetics of adaptive responses to drought stress Abscisic acid-dependent and abscisic acid-independent signaling components. Physiol Plantarum 123 111-119. 

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