Background: of SNP led to significant increase of vegetative

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Last updated: June 24, 2019

Background: SNP has recently been considered a new memberof the phytohormones, which plays an important role in different physiologicalprocesses.Objective: To evaluate the influenceof Sodium Nitroprusside (SNP) Foliar Spray on the Growth and PhysiologicalProcesses of Zea mays L. and Lablab purpureus (L.

) Sweet.Methodology: An experiment wasconducted to study the different concentration of SNP (1µM, 10 µM, 100 µM, 1mM and 10mM) foliar spray on 20 days oldseedlings of Zeamays L. Lablab purpureus (L.

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).Thetreatment was carried out for 2 days, and analyzed the various growthparameters, biochemical and enzymatic characters.Results: Our results showed that applicationof SNP led to significant increase of vegetative growth characters such asshoot and root length, shoot and root fresh weights and dry weights, pigment,composition and total soluble protein, total soluble glucose, free amino acid,NRA, proline, peroxidase and catalase activity. On unit fresh weight basis, thetotal chlorophyll content was found to increase at all concentrations. Also, SNP increased P and K, while Na, Ca andMg when compare to the control. Conclusion: The exogenous applicationof SNP to intact Zeamays L. Lablab purpureus (L.)seedlingswas found to be beneficial in promoting growth and biochemical responses inplants.

 Key words: Sodiumnitroprusside (SNP), Zeamays L. Lablab purpureus (L.),Physiological,Biochemical and Minerals. INTRODUCTIONSodium nitroprusside (SNP) represents one of the most commonly usednitric oxide (NO) donors. It was classified as a phytohormonethat might function as a gaseous endogenous plant growth regulator as well as anon-traditional plant growth regulator. They are naturally produced within plants and used to regulate theplant growth and developments.  NO acts as a signal molecule in plantsresponsible for the regulation of the expression of many defense-relatedenzymes.

 NO has gained increasinginterest as important intermediate and intracellular signaling molecule inplant systems which mediates variousphysiological, biochemical and developmental processes in plants, including seed dormancy, seed germination, primary lateral root growth,floral transition, flowering, stomatal movement, photosynthesis, mitochondrialfunctionality, senescence, plant metabolism and cell death as well as stressresponse (Paraiz Ahmad et al., 2016). In the past few years, a growing amount of researchhas provided evidence for the multiple physiological roles of this gaseous freeradical in plants (Delledonne, 2001; Wendehenne et al., 2004). The objective of thepresent study was to investigate whether sodium nitroprusside (SNP), a NOdonor, plays an important role in plant growth anddevelopments on the selected crop seedlings. MATERIALS AND METHODSCultivation of seedlingsHealthy and uniformseeds of Zea mays L.

Lablab purpureus (L.) Sweets were purchased from Agricultural Research Centre, Kovilpatti. Thepercentage of seed germination was found to be 80-85%. The seeds were sown inpots containing a mixture of red soil, black soil and sand mixed in theratio of 2: 2: 1. Soon after emergence of the cotyledons, the seedlings wereshifted to daylight conditions.  Since the ambient climate was too hot forthe seedlings, a 40% cut off mesh filter was used to surround the pots for aninitial period of 2-3 days.Sodium nitroprusside (SNP) treatmentSodiumnitroprusside was obtained from Sigma Chemical Co. (St.

Louis, U.S.A). SNP wasinitially dissolved in water and made up to 1µM, 10µM, 100µM, 1mM and 10 mMcontaining 0.02% Tween-20 (Polyoxy ethylene sorbitanmonolaurate). Each seedlingrequired about 10ml of spray solution. The foliar spray was given for two daysearly in the morning and growth analyses were done after 10 days of seedling growth.

The seedlings were sprayed with solutions until dropping with an atomicsprayer. Plants sprayed with 0.02% Tween-20 served as the control. After two days of the treatment the seedlings of Zea mays L. Lablab purpureus (L.)Sweet were used for measuring the growth parameters such as such as root length,shoot length, leaf area, fresh weight and dry weight were measured.

Thebiochemical and enzymatic characters were analyzed by the following methods:chlorophyll and carotenoids (Wellburn and Lichtenthalar, 1984), Anthocyanin andFlavonoid Mirecki and Teramura (1984), Total soluble sugar (Jayaraman, 1981),Protein content (Lowry et al., 1951), in vivo nitrate reductaseactivity (Jaworski, 1971), Catalase activity (Kar andMishra, 1976) and Peroxidase activity (Addyand Goodman, 1972).   RESULTSAND DISCUSSIONFormerly, the plant hormone ethylene was the only gaseoussignaling molecule in the living world known to science(Ferreira and Cataneo – ?2010DNS1 ).However, work on nitric oxide fetched the Nobel Prize for Medicine in 1998(Wojtaszek, 2000), and considered as a signalling molecule.NO has been initially identified as an endothelium-derived relaxation factorand later implicated in signal transduction pathways controllingneurotransmission, cell proliferation, programmed cell death, and hostresponses to infection (Wink and Mitchell, 1998).

Although the history of studieson NO in animals is considerably much more advanced, renewed attention has beengiven to the mechanism of NO synthesis and its functions in plants in the lastdecades.Effectof SNP on growth characteristics The exogenousapplication of SNP increased the level of shoot length, root length, shootfresh weight, root fresh weight and dry weights. There are several reports thatsuggest the growth promoting activity of SNP. Huang and She (2003) reported that SNP induced adventitiousroot formation in mung bean hypocotyl cuttings. Correa-Aragunde et al.

(2004) demonstrated that NO andits precursor SNP playing a key role in determining lateral root development intomato. In addition, NO and SNP promoted root elongation in maize (Gouvea et al., 1997). Theroot growth increased by about 30% in seedlings pre-treated with 0.4 mM SNP(followed by10 ?M Al treatment) as compared to control (10 ?M Al alone).

Inorder to confirm the role of SNP in reducing Al-inhibited root growth, a rootgrowth recovery experiment was carried out. Roots pre-treated with 0.4 mM SNPfor 12 h followed by the 20 ?M Al treatment for another 12 h were found to beless inhibited and recovered more rapidly than the roots without SNPpre-treatment. After a 72 h period of recovery, the SNP-pre-treated rootelongation reached 60% of the control (–Al treatment), whereas the rootelongation without SNP pre-treatment was only 22% of the control. In thepresent study all the concentrations of SNP increases the shoot fresh weightand dry weight. The changes in shoot dry weight are a clear representation ofthe vegetative growth.

Effect of SNP on biochemicalconstituents The chlorophyll aand chlorophyll b were found toincrease with increase in concentration of SNP in Zea and Lablab purpureus. The level ofchlorophyll b which was high underSNP treatment indicates changes in stoichiometry of PS II and PS I. As Chl b is associated more with PS II, anysignificant change in Chl b levels,would indirectly affect the efficiency of PS II rather than PS I.  Our results indicated that application of SNPsignificantly increased Chl content in leaves which might be due to theimpairment of Chl biosynthesis. There are many processes in which hormones andphytochrome interact or act separately to give the same response.

NO alsotriggers several of these responses. These overlapping roles raise the questionof whether light and hormones share common components in signal transductionpathways to elicit the same response and whether NO role play in the signalingcascade (Lamattina et al., 2003).            Treatment with SNP increasesd anthocyanin and flavonoidscontent. The anthocyanin and flavonoids are non-photosynthetic pigmentstaking part in plant defense mechanisms. The effect of these non-photosyntheticpigments depends on the environmental factors like light temperature, drought,radiation stress etc. Have suggested that theconcentration of surface flavonoids decrease with leaf age in all plants.

Both anthocyanin and flavonoids tend to accumulate more in foliar tissues attimes of abiotic stresses. High concentrations of the phytohormones lead to thedevelopment of these pigments in order to protect the seedlings against theaction of SNP oxidase.                 Foliar application of SNP caused markedincreases in the total soluble proteins in exogenous application of SNPsubjected samples of Zea maysand Lablab purpureus.  Thisresult was supported by Nasrin et al.(2012).  It may be substantiated by the activeparticipation of an enzyme activity nitrate reductase (reduction of nitrate tonitrite and then to aminoacids) and increase in the polyribosome and proteinsynthesis.

The changes in leaf nitrate content and in vivo nitrate reductase activity reveals the high concentrationof SNP favored the accumulation of may be due to enhancement of nitrogen ornitrate uptake by plants. A key step in nitrate assimilation is thereduction of this anion to nitrite in the reaction catalyzed by NR, an enzymethat is highly regulated at the transcriptional and post- transcriptionallevels (Kaiser, 2001). NR has been studied extensively as a key enzyme ofnitrogen metabolism. NR activity was significantly enhanced by the addition ofSNP.

NR activity was significantly stimulated by SNP at 100µM and 10mM.  The reason behind is that NO stimulate thepost translational regulatory pathway of NR. All this results indicate foliarapplication of SNP is important for enhancing NR activity.

SNPtreated plants in our study showed increases in peroxidase activity at all theconcentration of SNP. The higher level of endogenous auxins could also lead toearly sprouting of leaves. The high rate of peroxidase activity may be due toenhanced auxin catabolism triggering the root initiation process (Kochhar et al., 2005).

While SNP oxidase seems tobe involved only in triggering and initiating the root / shoot primordiaperoxidase is involved in both root initiation and elongation processes andoxidation products of auxin catabolism may be involved in the initiation ofroots.   DNS1Don’tcopy any of the sentences./ otherwise give proper citations.

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