Effects of exogenous nitric oxide on photosynthesis, antioxidative ability, and mineral element contents of perennial ryegrass under copper stress

Abstract

A hydroponics experiment was conducted to test the effects of sodium nitroprusside (SNP, a donor of NO) supplied with different concentrations on copper (Cu) toxicity in ryegrass seedlings (Lolium perenne L.). Excess Cu (200 µM) reduced chlorophyll content, resulting a decrease in photosynthesis. Cu stress induced the production of hydrogen peroxide (H 2 O 2) and superoxide anion (O 2 • −), leading to malondialdehyde (MDA) accumulation. Furthermore, activities of antioxidant enzymes in Cu-treated seedlings such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were decreased. In addition, Cu stress inhibited the uptake of K, Mg, Fe, and Zn and increased Ca content in roots. Moreover, in leaves of Cu-stressed seedlings, K, Fe, and Zn contents were decreased and the contents of Ca and Mg were not affected significantly. In Cu-treated seedlings, Cu concentration in roots was higher than in leaves. Addition of 50, 100, 200 µM SNP in Cu-mediated solutions increased chlorophyll content and photosynthesis, improved antioxidant enzyme activities, reduced Cu-induced oxidative damages, kept intracellular ion equilibrium under Cu stress, increased Cu concentration in roots and inhibited Cu accumulation in leaves. In particular, addition of 100 µM SNP had the best effect on promoting growth of ryegrass seedlings under Cu stress. However, the application of 400 µM SNP had no obvious alleviating effect on Cu toxicity in ryegrass seedlings.

Use of Nitric Oxide and Hydrogen Peroxide for Better Yield of Wheat (Triticum aestivum L.) under Water Deficit Conditions: Growth, Osmoregulation, and Antioxidative Defense Mechanism

“…In the current experiment, a similar increasing trend in cellular GB, proline, and total soluble protein contents was observed in both studied wheat cultivars as a result of exogenously applied SNP, H 2 O 2 , and SNP + H 2 O 2 as seed primers, which induced a greater protection to plants under stressed conditions. NO-induced enhanced accumulation of these osmolytes correlates well with the findings for several plant species that have already been studied [44,91,92]. As a ROS scavenger, proline acts as a non-enzymatic antioxidant of 1 O 2 and OH.…”

“…Nitric oxide has the potential to decrease the levels of H 2 O 2 and lipid peroxidation under water stress [43]. Exogenously-applied nitric oxide (NO) also improves the plant biomass production and leaf chlorophyll biosynthesis by improving the activities of antioxidants to reduce the damages caused by oxidative stress [44,45]. Nitric oxide signaling also plays an important role in plant disease resistance [46] in response to several abiotic stresses [5,7,8,47].…”

Role of nitric oxide in improving seed germination and alleviation of copper-induced photosynthetic inhibition in Indian mustard

“…SNP application also has some positive role in improving the activity of Rubisco enzyme and ultimately enhancing photosynthetic activity. The study is supported by numerous findings such as protection of chlorophyll damage and enhancement in photosynthetic pigments in NO-treated Lolium perenne under Cu stress [61], Helianthus annuus exposed to Cd stress [62], Triticum aestivum [63], B. juncea under salt stress [54]. Treatment of cucumber seedlings, with SNP enhanced the chlorophyll content, rate of photosynthesis, and transpiration rate and stomatal conductance [64].…”

Mechanisms of Environmental Stress Tolerance in Turfgrass

“…It was reported that signal messengers such as NO, hydrogen sulfide (H 2 S) and glycinebetaine (GB) play crucial roles in alleviating cadmium and Cu-induced damages in bermudagrass and perennial ryegrass [59,66,67]. Investigation of perennial ryegrass showed that NO could increase Cu accumulation in roots rather than in leaves [68]. Moreover, the rare element cerium (Ce) was reported to improve the copper tolerance of Poa pratensis by regulating ascorbate and glutathione metabolism pathways [61].…”