Specific and unspecific responses of plants to cold and drought stress

Abstract

Different environmental stresses to a plant may result in similar responses at the cellular and molecular level. This is due to the fact that the impacts of the stressors trigger similar strains and downstream signal transduction chains. A good example for an unspecific response is the reaction to stressors which induce water deficiency e.g.drought, salinity and cold, especially frost. The stabilizing effect of liquid water on the membrane bilayer can be supported by compatible solutes and special proteins. At the metabolic level, osmotic adjustment by synthesis of low-molecular osmolytes (carbohydrates, betains, proline) can counteract cellular dehydration and turgor loss. Taking the example of Pinus sylvestris, changes at the level of membrane composition, and concomitantly of photosynthetic capacity during frost hardening is shown. Additionally the effect of photoperiod as measured via the phytochrome system and the effect of subfreezing temperatures on the incidence of frost hardening is discussed. Extremely hydrophilic proteins such as dehydrins are common products protecting not only the biomembranes in ripening seeds (late embryogenesis abundant proteins)but accumulate also in the shoots and roots during cold adaptation, especially in drought tolerant plants. Dehydrins are characterized by conserved amino acid motifs, called the K-,Y-or S-segments. Accumulation of dehydrins can be induced not only by drought, but also by cold,salinity,treatment with abscisic acid and methyl jasmonate. Positive effects of the overexpression of a wild chickpea (Cicer pinnatifidum) dehydrin in tobacco plants on the dehydration tolerance is shown. The presentation discusses the perception of cold and drought,the subsequent signal transduction and expression of genes and their products. Differences and similarities between the plant responses to both stressors are also discussed.

Plant growth-promoting bacteria effect in withstanding drought in wheat cultivars

“…Reduction in electrolyte losses under water stress results in a better membrane integrity and tolerance to oxidative stress (LIU et al, 2011 Inoculation with A. brasilense induced homeostatic mechanisms that generate tolerance to drought in prime wheat (KASIM et al, 2013). Moreover, drought increases reactive oxygen species production (BECK et al, 2007), which can damage cells and activate defense responses to water stress (DOORNBOS et al, 2012;FAROOQ et al, 2009). The MSI of inoculated plants of the cultivar CD-120 indicated a protection against oxidative damage using the bacteria as a biopriming (BECKERS et al, 2007, COMPANT et al, 2005PIETERSE, 2012;MASWADA;EL-KADER, 2016).…”

“…Plants have developed adaptive physiological responses to cope with drought stress, such as reduction of transpiration by fast stomatal closure, decreasing of photosynthetic activity and deepening of roots (ALI et al, 2013;BECK et al, 2007). Plants with high antioxidant levels usually have greater tolerance to oxidative damages due to water stress (APEL; HIRT, 2004).…”

Phenological and Growth Responses of Indian Mustard (Brassica juncea L.) Genotypes to Different Sowing Dates

“…The global mean surface air temperature increased by 0.5°C in the twentieth century and is expected to increase a further 1.5-4.5°C by the late twenty-first century (IPCC, 2012).Climate change has increased the intensity of heat stress and heat stress due to increased temperature is an agricultural problem in many areas in the world as well as in India (Beck et al, 2007).…”

Influence of Salt Stress on Growth and Frost Resistance of Three Winter Cereals

“…The reaction of plants to a single stress factor, such as low temperature (Beck et al, 2007;Mahajan and Tuteja, 2005) or salinity (Chinnusamy et al, 2005;Flowers, 2004;Mohammadi et al, 2012;Munns, 2002), is fairly well recognized. The response of cultivated plants to stress caused by a number of stress factors factors is a more complex issue, as in natural conditions, plants are usually exposed to multistress.…”