Antioxidant responses of lentil and barley plants to boron toxicity under different nitrogen sources

Abstract

In this study, the effects of different nitrogen sources on lentil (Lens clunaris) and barley (Hordeum vulgare) plants, exposed to 5 and 10 mM boron stress previously, were studied. After ten-day germination, the lentil (native) and barley (Tokak157/37) were incubated 16 h light and 8 h dark per day for 7-day growth cycle under the conditions of boron stress via different nitrogen sources (10 mM nitrogen in NH 4 Cl, KNO 3 and urea). As a result of the changes in the nitrogen sources of the plants, there were determined decreases in the relative growth rate (%) and total chlorophyll content related to boron stress, (p < 0.05) and (p < 0.01), respectively. The changes in the lentil were obtained much more than those in the barley. In addition, the changes in the groups in which NH 4 + was used as nitrogen source were obtained at lowest levels. The concentrations of MDA, H 2 O 2 and proline showed increases under boron stress (p < 0.05). The effect of boron toxicity on the activities of SOD, GPX and LOX was similar in the two species but the levels of CAT and APX activities were different in both species under 5 and 10 mM boron stress (p < 0.01). SOD, GPX and LOX activities increased in the roots and shoots of boron treated plants as compared with the controls (p < 0.01). Although, lentil CAT and APX, activities decreased; in barley, CAT and APX, activities increased under boron toxicity. In conclusion, the fertilizers which contain NH 4 + should be used in the boron stressed farmlands.

Boron phytoremediation: Stizolobium aterrimum is tolerant and can be used for phytomanagement of boron excess in soils

“…Excess of boron interferes in nitrate reductase activity and thus affect the synthesis of amino acids [28], in special glutamic acid that can lead to imbalance in chlorophyll production once this molecule is synthesised from alpha-aminolevulinic acid, derived from glutamic acid. So, as we did not find any effects in chlorophyll content we could assume that it had no effect on nitrogen metabolism, although we showed some opposite results for other plants in another study [29]. In that work, nitrogen sources were evaluated to overcome B toxicity in lentil and barley plants and the authors found a decrease in chlorophyll content in both species.…”

Tolerance of Plants to Toxicity Induced by Micronutrients

“…The chlorophylls are responsible to the photochemical and biochemical reactions during light capitation [61], while carotenoids present an important role related to photoprotection against excessive sunlight [62], given that both pigments work simultaneously into photosynthetic machinery [63]. However, the excessive B supply represents a problem to photosynthetic pigments, with consequent decrease in chlorophylls [64][65].…”