Description

It is becoming clear that hydrogen sulfide (H₂S) is a crucial gaseous molecule that plays a role in a variety of plant developmental processes and stress responses. The purpose of this study was to investigate how H₂S responds to iron deficiency in wheat plants treated with an exogenous H₂S donor (sodium hydrosulfide, NaHS).

Because of its significant role in a variety of cellular metabolic processes, iron (Fe) is an essential nutrient for all organisms. Iron is abundant in soils, but it is not readily available in a form that plants can absorb and utilize. Up to 40% of the world's arable land may be iron-deficient, and the issue is especially serious in alkaline soils because the availability of iron decreases with soil pH. Iron deficiency in plants has become a global concern. It typically results in a decrease in chloroplast particles and thylakoid lamellae, alterations to the arrangement of the basal and matrix thylakoid, and even chloroplast dissociation. In plants, the redox reaction and electron transport both rely heavily on iron; hence, iron-inadequacy ordinarily debilitates photosynthesis and breath, in this manner influencing plant yield and quality. In important crops like rice, spinach, and tomatoes, iron has been shown to be a constraint on biomass.

Lateral Root In addition to NO and CO,H₂S is an important gas signaling molecule that has been extensively studied in recent years for its physiological role in plants.H₂S also causes responses to various abiotic stresses and regulates the physiological processes of plant stomatal closure, seed germination, root development, and senescence.H₂S also plays a role in the NO, auxin, and ethylene signal pathways. By inducingH₂S production, for instance, NO improves Cynodon dactylon's resistance to Cadmium (Cd) stress; H₂S mediates ethylene-regulated stomatal closure in Arabidopsis thaliana and lateral root development in tomato, both of which are regulated by auxin. Iron-inadequacy prompts plant chlorosis, chlorophyll decrease and photosynthesis hindrance. Under normal conditions, studies have demonstrated that H₂S can improve rice and spinach photosynthesis, as well as strawberry and wheat chlorophyll fluorescence under drought stress. It is not clear whether H₂S is involved in the regulation of plant iron nutrition, despite the fact that it has been shown to play a role in the NO, auxin, and ethylene signaling pathways, all of which are responsible for eliciting responses in response to iron deficiency. However, under both normal conditions and Cd stress, it has been demonstrated that H₂S increases iron uptake in rice roots and leaves. Based on these outcomes, the impacts of H₂S on wheat development, chlorophyll content, photosynthesis, PSs delivery and Fe content in wheat under Fe-lacking and adequate circumstances were researched. Because wheat is an important crop and a Strategy II plant that releases PSs when Fe is low, it was considered a research object.

Seedling Roots

Surface-sterilized and germinated for 48 hours on watersoaked filter papers, the seeds of the common cultivated wheat variety Aikang 58 were then grown in a 1/2 strength Hoagland nutrient solution. After three days, the seedlings were moved to Fe-adequate (50 mM) and lacking (0 or 1 mM) supplement arrangement regardless of 0.4 mM NaHS and the supplement arrangement was changed at regular intervals. After two weeks, the third leaf was used to measure the amount of chlorophyll and Photosynthesis (Pn), and all of the leaves were used to measure the amount of H₂S and Fe. The PSs content in root washing was used to analyze PSs release from seedling roots. Morphological Changes Harvested seedlings were washed twice in 5 mM CaSO4 and 10 mM EDTA solution and then dried at 70°C after treatment. Root systems of wheat seedlings were then transferred to 200 ml deionized water for 6 hours. At 120°C, the samples with a weight of at least 0.2 g were completely digested in 70% HNO3. Finally, distilled deionized water was used to dilute the solution to a certain volume. Inductively coupled plasma spectrometry was used to measure the amount of iron. At least three distinct experiments were used to collect all of the data. At least six leaves were used to measure photosynthesis. For different examinations, the outcomes were the mean of three recreated medicines. Duncan's multiple range tests at a 0.05 probability level were used to compare the treatments' mean differences.

H₂S still up in the air in the two shoots and foundations of wheat plants filled in Fe-adequate and restricted culture arrangements. When compared to the Fe-sufficient group, the H₂S content increased in leaves by 145% and decreased in roots by 50% under Fe-limited conditions. In both Fe-limited and Fesufficient conditions, the H₂S content in the leaves and roots of the group treated with exogenously applied NaHS was higher than in the group treated with no NaHS. Under Fe-sufficiency conditions, the increase was 21.2 percent for the leaves and 253.6 percent for the roots, whereas under Fe-limited conditions, it was 41.9% and 307.1%.

Lateral Root

In order to adapt to Fe-limited conditions, plants undergo a variety of morphological and physiological modifications. The increase in Lateral Root (LR) development, which has been demonstrated in tomato and Arabidopsis, is one of these changes. According to a different study, NO regulates Fedeficiency- induced root branching, which increases tomato's tolerance to Fe deficiency and this regulation occurs after auxin. As of late, the job of H₂S in horizontal root advancement has additionally been researched. Pepper lateral root formation was induced by NaHS treatment, whereas hypotaurine, and H₂S scavenger, had the opposite effect. In Arabidopsis thaliana seedlings, H₂S promotes LR initiation while inhibiting primary root, LR, and root hair elongation. NaHS also restores auxin depletion-induced inhibition of lateral root formation. Under both Fe-deficiency and sufficiency conditions, NaHS treatment significantly increased the number, density, and length of lateral roots in this study. Combining these and previous findings, we concluded that the regulation of lateral root development was related to H₂S's effect on reducing wheat Fe deficiency. This study revealed that wheat plants' response to Fe deficiency is heavily influenced by H₂S. Specifically, H₂S can boost PSs secretion and iron uptake, which in turn can boost photosynthesis and biosynthesis of chlorophyll. Although this study sheds light on the role that H₂S plays in plants' responses to Fe deficiency, additional research is required to comprehend H₂S's regulatory mechanism for PSs secretion and iron uptake.