On the interaction of UV‐B radiation (280–315 nm) with water stress in crop plants

Abstract

Cowpea (Vigna unguiculata L. Walp.) seedlings (3‐day‐old) were subjected to 4 kinds of experimental treatments: (1) control without exposure to any stress (−D‐UV), (2) moderate water stress with no UV‐B irradiation (+D‐UV), (3) no water stress but to UV‐B radiation (−D+UV). and (4)moderate water stress and exposure to UV‐B (+D+UV). UV‐B and drought stress in the combined form elicited beneficial effects on the morphological and growth characteristics, and a few additive inhibitory effects in some functional processes. An increase in the specific leaf weight (SLW) was observed in the combination of stresses, which could be a defence mechanism against UV‐B. The combination of stresses promoted the synthesis of anthocyanins and phenolic compounds. The responses of plants to the combination of stresses indicate that during simultaneous exposure of plants to multiple stresses, one form of stress could minimize the damage by the other. The enhancement of superoxide dismutase (SOD) and catalase activities appear to serve as acclimation mechanisms to scavenge the toxic, free radicals of oxygen produced under stress conditions. However, the inhibition in nitrate metabolism was greater in the combined stresses than in either of the stresses imposed separately. The results of this study illustrate that the interaction of stresses during simultaneous multiple stress conditions brings out certain beneficial effects.

The adaptive significance of autumn leaf colours

“…There is mounting evidence to suggest that the accumulation of anthocyanins in plants is environmentally regulated (Chalker‐Scott 1999, Leng and Qi 2002). The photoinduction of anthocyanins in plant tissues is a well‐documented process (Mol et al 1996), particularly when combined with exposure to low temperature (Krol et al 1995), nutrient deficiency (Bongue‐Bartelsman and Phillips 1995, Trull et al 1997) and drought (Balakumar et al 1993). Of course one could argue that in these cases the stresses make the need to signal unprofitability to potential herbivores even more important.…”

Association between winter anthocyanin production and drought stress in angiosperm evergreen species

“…Specifically, anthocyanin synthesis is known to be inducible under high salinity (Dutt et al , 1991; Ramanjulu et al , 1993; Kaliamoorthy and Rao, 1994; Eryilmaz, 2006), drought (Spyropoulos and Mavrommatis, 1978; Balakumar et al , 1993; Sherwin and Farrant, 1998; Yang et al , 2000), and sugar treatments (Sakamoto et al , 1994; Suzuki, 1995; Tholakalabavi et al , 1997). Furthermore, species with high levels of foliar anthocyanin seem to be common in environments characterized by low soil moisture (Spyropoulos and Mavormmatis, 1978), and are more tolerant of drought conditions (Diamantoglou et al , 1989; Knox, 1989; Beeson, 1992; Paine et al , 1992).…”

Reduction of chilling injury in stored avocado, grapefruit, and bell pepper by methyl jasmonate

“…According to this hypothesis, plants respond with similar defense systems to a wide range of stresses such as osmotic, chemical pollutants, oxidative, salinity, cold or heat, UV, low oxygen, pathogen infection, and wounding (Balakumar et al 1993;Chapin 1991;Lurie and Klein 1991;Maslenkova et al 1992;Vierling and Kimpel 1992). According to this hypothesis, plants respond with similar defense systems to a wide range of stresses such as osmotic, chemical pollutants, oxidative, salinity, cold or heat, UV, low oxygen, pathogen infection, and wounding (Balakumar et al 1993;Chapin 1991;Lurie and Klein 1991;Maslenkova et al 1992;Vierling and Kimpel 1992).…”