Alleviation of photosynthetic inhibition in copper-stressed tomatoes through rebalance of ion content by exogenous nitric oxide

Abstract

Copper (Cu) is an essential element that plays a very important role in plant growth and development. Its accumulation in soil is now considered a serious environmental problem endangering agricultural production and human health. In this study, the influence of exogenous nitric oxide (NO) on photosynthesis, Cu, magnesium (Mg), and iron (Fe) contents was studied in tomato seedlings under Cu stress grown in hydroponic culture. The results showed that the addition of sodium nitroprusside (SNP), a donor of exogenous NO, significantly alleviated photosynthetic inhibition in Cu-stressed tomatoes, including the recovery of photosynthetic pigment content and chlorophyll a fluorescence and the improvement of net photosynthetic rate, stomatal conductance, and transpiration rate. Application of exogenous NO by SNP reduced the excessive accumulation of Cu and recovered Mg and Fe contents in Cu-stressed tomatoes. This positive involvement of exogenous NO in tomato tolerance to Cu stress was further confirmed by addition of 2-(4-carboxyphenyl)-4,4,5,5tetramethylimidazoline-1-oxyl-3-oxide (cPTIO), a specific NO scavenger, which resulted in further reduction of photosynthesis and more severe disturbance of ion homeostasis in Cu-stressed seedlings. These results indicate that rebalance of ion content was involved in alleviation of photosynthesis inhibition in Cu-stressed tomatoes by exogenous NO.

An efficient antioxidant system and heavy metal exclusion from leaves make Solanum cheesmaniae more tolerant to Cu than its cultivated counterpart

“…; Al Khateeb and Al‐Qwasemeh ; Wang et al. ). However, an integrative study focused in the interplay of oxidative stress and antioxidant defense in response to Cu was still missing in S. lycopersicum, and the effect of Cu on the wild species S. cheesmaniae was so far unknown.…”

“…; Al Khateeb and Al‐Qwasemeh ; Wang et al. ). However, in this study, although we have completed and performed some analyses in this species, the main purpose was to compare the responses of S. lycopersicum to its wild counterpart Solanum cheesmaniae, potentially more tolerant to Cu because it is considered a salt‐tolerant species (Rajasekaran et al.…”

Variation in trace element mobility and nitrogen metabolism ofVerbascum olympicum Boiss. under copper stress

“…It was reported that rebalanced ion content is involved in alleviating photosynthesis inhibition in Cu-stressed tomatoes by exogenous NO. [19] In addition, acute Cu stress is suggested to be alleviated by NO via modulation of superoxide and hydrogen peroxide levels, reflecting the necessity for a well-coordinated interplay between NO and reactive oxygen species during stress tolerance in Arabidopsis thaliana. [20] Verbascum olympicum Boiss.…”

Effect of Drought Stress (Mannitol) on Morphological Physiological Activity and Anatomy of Cow Pea Plant(Vigna unguiculata)

“…Decreased or unchanged chlorophyll level during drought stress has been reported in other species, depending on the duration and severity of drought [5] A decrease of total chlorophyll with drought stress implies a lowered capacity for light harvesting. Since the production of reactive oxygen species is mainly driven by excess energy absorption in the photosynthetic apparatus, this might be avoided by degrading the absorbing pigments [12]. …”

“…Under drought stress, the responses deal with the stimulated production of reactive oxygen species (ROS), (eg singlet oxygen, superoxide radical, hydrogen peroxide, hydroxyl radical [4] that cause membrane injuries, protein degradation, enzyme inactivation and thus induce oxidative stress [22].The main injuries under high temperatures include protein denaturation and increased fluidity of membrane lipids and inactivation of enzymes, reduced synthesis and degradation of proteins, and defaults in membrane integrity [12] Severe cellular injury or death may occur at moderately high temperatures after long-term exposure or within minutes at very high temperatures [13] These injuries may result in reduced ion flux and plant growth, and production of toxic compounds and reactive oxygen species likewise under water deficit. POD also involved in various plant processes, including lignification [12][15].The tolerance of some genotypes to environmental stresses has been associated with higher activities of antioxidant enzymes. For example, the drought-tolerant species of pigeon pea (Cajanus cajan) [21] wheat (Triticum aestivum) [18] [19].…”