Unlocking Growth Potential: Enhancing Salt-Stressed Seed Germination and Seedling Growth with Ga 3 Priming in Acacia auriculiformis A.cunn. ex Benth., Delonix regia (Bojer ex Hook.) Raf. and Cassia fistula L.

Gibberellic acid (GA 3 ) is the one of the plant growth regulator which helps plants tolerate salt competently and diminishes the effects of salt stress. The present investigation was done to determine the effect of GA 3 on two different Nacl concentrations on seed germination and physiological limits of four fabaceae seeds: Acacia auriculiformis A. Cunn. ex Benth., Delonix regia (Bojer ex Hook.) Raf., Cassia fistula L., and Samanea saman (Jacq.) Merr. Experimentation was directed as a factorial with a completely randomised block design with three replicates. Salinity at two levels (50 mM and 100 mM NaCl) and hormone (GA 3 at 150ppm versus no GA 3 were the experimental conditions. Therefore, when the salt level was 50 mM NaCl, priming the seeds of these tree seeds with 150 ppm GA 3 suggestively increased germination percentage, declined mean germination time, improved physiological parameters of the seeds


Introduction
Salinity, which is persuaded by a greater amount of salt in the soil and affects the considerable amount of the plant and is an major issue for most plants particularly in areas with hot, dry conditions, and is one of the most severe issues inhibiting crop plant germination and productivity. 1,2The contrary impacts of high soil salinity levels due to the combination effects of large osmotic potential, ion toxicity, and capacity of plant production, lead to destroying seed germination, seedling growth, and developmental phases. 3,4The germination percentage, physiological parameters were all remarkably abnormal, and this is due to the higher salt concentration. 1 Plants suffer from two direct problems in saline environments, there is quite a lot of salt in the soil which shrinkages the osmotic potential of the soil solution, which further causes less water to be absorbed by plants and a water deficit.Moreover, increased Na + and Cl-ion absorption renders plants toxic by preventing them from gripping vital nutrients. 5,6ytohormones are endogenously produced organic substances essential for regulating plant growth and productivity.This hypotheses states that the gibberellins acid seems to be critical modules of complex gesturing networks and have been integrated into current models of stress response. 9ence, they play an important role in prompting plant tolerance to various stress conditions GA 3 plant growth regulators are highly active for encouraging and optimising the plant development, and photosynthetic activity because they are also notorious to trigger numerous physiological responses in plants. 7 saline conditions, patterns of growth reduction can occur; this can be decreased by the advanced effectiveness of exogenous GA 3 application on different activities of the plants.The use of GA 3 helps diminish saline stress, and its adeptness is more vigorous in salt resistant cultivars. 8y improving vigour, anti-oxidation enzyme activity, and the accretion of osmolytes, gibberellic acid slightly alleviates the deleterious effects of salinity.Additionally, GA 3 treatment promotes the production of the hydrolytic enzyme, which is required to break down endospermic starch when seeds renew growth during seed germination. 9,10nsequently, the goal of the present study was to appreciate the germination activity and seedling growth through priming with GA 3 in seeds of Acacia auriculiformis A.Cunn.ex Benth.(Ear-pod Wattle), Delonix regia (Bojer ex Hook.)R af. (Royal Poinciana), Cassia fistula L. (golden shower tree), and Samanea saman (Jacq.)Merr (Rain Tree).In addition, the seeds were also treated with NaCl to symbolise their tolerance capacity during germination and the early seedling growth stages.

Seed Collection
The mature seeds of Acacia auriculiformis, Delonix regia, Cassia fistula, Samanea samand an (Fabaceae) were collected during September to December 2020 from the Western Ghats, Sadivayal area in Coimbatore district (11.0168°N, 76.9558° E).The collection site has a mean temperature of 27°C ranging from 32°C in September to 19°C in December.Several hundred seeds were collected from 10 randomly chosen trees located within a 20-km radius by gently shaking the mature trees.Seeds were transported to the lab via road on the same day, visually inspected, and any unhealthy seeds and debris were removed.The seed surface was sterilized with 2% sodium hypochlorite solution for 10 minutes and thoroughly washed with distilled water 6 to 8 times.The seeds were then bench dried for a day and subsequently stored in air-tight glass bottles under room temperature(27°C) and humidity (30to 50%)until used in the experiment.

Hormonal Priming
The seeds were soaked with 150 ppm GA 3 solution for 12 hours at 27°C in darkness, achieved by covering the petri dishes with two layers of aluminium foil paper.After GA 3 treatment, seeds were removed and washed in running tap water and then rinsed three times with distilled water.Seeds were dried by placing them between filter papers.After drying, the seeds were kept in petri dishes containing moist no.1 Whatman filter paper in room condition at 27°C.Control seeds (no GA3 treatment) are soaked in water for 12 hours, re-dried, and then placed in petri dishes containing moist no.1 Whatman filter paper in room condition at 27°C.
A fully randomized factorial experiment consisting of three replicates of 25 seeds each from control and primed groups were moistened with equal volumes of NaCl solutions at two different concentrations: 50 mM and 100 mM.Physiological factors were calculated by formulae given below.The shoot and root lengths of all seedlings were measured using a transparent ruler.Seedlings fresh weights were measured using a weighing balance.Seedlings were dried in hot air oven at 50°C for 2 days, and then dry weights were documented. 11,12asurements of germination efficiency Total germination (TG) were calculated every day and terminated at end of day 15 after sowing. 11t was computed as: Where n is the total germinated seeds, and N is the total seeds were sown.The Vigour index (VI) were measured using the formula of 14 VI= TG% × Seedling Length (cm)/100

Statistical Analysis
All data collected from the experiments were exposed to analysis of variance (Two way ANOVA) using the Statistical Package of the SPSS, version 20 software and the difference between means were calculated by Fisher's Post Hoc Least Significance Difference Test at P < 0.05.

GA 3 treated and control seeds of Acacia auriculiformis
A.Cunn.ex Benth., Delonix regia (Bojer ex Hook.)Raf.Cassia fistula L. and Samanea saman (Jacq.)Merr were spread and moistened with different concentrations of Nacl solutions, and the significances of the study were composed by significant various physiological parameters.

Germination Rate and Germination Mean Time of the four Fabaceae Seeds
By variance of analysis presented that both Nacl and treated with GA 3 pointedly affected the germination rate and mean germination time of Acacia auriculiformis, Delonix regia, Cassia fistula, and Samanea saman seeds (P < 0.05) (Table 1

Germination Rate and Germination mean Time of the Four Fabaceae Seeds
Improving the salt tolerance of crops is an essential target of plant breeders, in aiming to meet the future food demands of coming generations. 23Presowing priming with GA 3 is used to accelerate seed germination and standardized seedling emergence, to enhance further plant growth, and to establish the stress resistance of seedlings and adult plants, which ultimately increases crop production. 24e significant and crucial stages in the life sequence of plants is seed germination, which has an impact on plant establishment and productivity.Moreover, a number of abiotic stresses can obstruct seeds from germinating, and salt in particular has a variety of dissimilar consequences.But the recent work is in accordance with 15 reported that plants use the buildup of some inorganic ions or organic compounds to balance the osmotic potential against the early problems of salinity, which prevents water uptake by the roots due to excessive ion content in the soil solution.When seeds were sown at different salt levels, the rate of germination and the amount of time required for germination were directly correlated.Seed priming with 150 ppm GA 3 upgraded the effect of Nacl on seed germination.According to reports, GA 3 increases the germination rate and counteracts the negative effects of saline stress on germination. 16 a general response to salt stress, plant growth is affected negatively by a variety of physiological changes, such as osmotic shock, ion toxicity, and nutritional imbalance. 23This study showed that, although stem length, fresh and dry weight, and water content decreased the adverse effect of NaCl by GA 3 treatment, the impact of GA 3 was reduced slightly with rising salt level.It has been known that, GA 3 enhances plant growth by promoting cell division and elongation 24 under salinity, for instance in arabidopsis, 25 wheat 26 and rice 8 The improvement of water absorption and cell wall flexibility, as well as the stimulation of cytological enzymes, all contribute to GA 3 's role in germination percentage. 17Comparable outcomes were observed on the germination of oats18, Hordeum vulgare, 19 Lathyrus sativus, 20 Ricinus communis, 21 Satureja thymbra, 22 Triticum aestivum, 23 and Phaseolus mungo. 24

Effect of Salinity And Ga 3 on the Physiological Growth Performance of the Four Fabaceae Seeds
In spite of optimistic beyond-minced growth in the dwarf lines, 25 testified that GA 3 had adverse possessions on length of root in the Rht12 dwarf of wheat plants by reducing overall root length and root dry weight in higher concentration of Nacl.The destructive effect was more prominent in the root than the shoot because plants under salt stress have less water-absorbent roots that develop more gradually 26.27 projected that the possessions of exogenously administered GA 3 on the removal of salt stress may be due to the activation of specific enzymes involved in RNA and protein synthesis. 28ound that GA3 treatment increased both the shoot and root development of soybean plants.
Consistently, several previous studies 30,31 have also documented that salinity is highly detrimental to plant growth.Salt stress in Zea mays reduced the root and shoot length, dry and fresh biomass and leaves growth compared to the control.The decrease in plant biomass might be due to the higher Na+ ion concentration in roots and outside the plant cell. 33In the soil, higher salt concentration limits the absorption of water and nutrients by plant roots.
This could be due to the exogenous application of GA 3 , which has generally stimulated oat plant development parameters and reduced the oppressive effect of salt stress to some extent.GA 3 can also improve the weights of seedlings, which also speeds up the step of photosynthetic growth, 29 Similar findings were made by, 24 who showed that saline lowered the weight of plants.The inhibitory effect of salt stress on Cucurbita pepo biomass was alleviated partially or entirely by all investigated hormonal treatments.In accordance with our results, other studies reported that treatment of plants with GA 3 is efficient in relieving salinity stress effects at various stages of plant growth by enhancing plant height, root length, root diameter, and shoot fresh weight. 30eir findings recommended that the loss of fresh and dry biomass at higher concentrations may be due to inadequate water absorption from the growth medium as a result of physiological dryness.
It utilises several kinds of growth-promoting hormones to boost productivity in agriculture.Gibberellic acid (GA 3 ), one of the main plant hormones, regulates when plants grow and develop as well as how it impacts blooming, leaf, stem, and seed germination.GA 3 application has been shown to improve plant growth by altering the ratio between endogenous ABA and SA, reducing the quantity of polyamines, which are involved in the regulation of aging 7 and GA 3 can induce salt tolerance in plants by increasing CK and IAA, it seems that sorghum is able to survive under salinity with less damage through changes to CK and IAA levels 35 Investigate those gibberellins normalize numerous plant metabolic processes by interacting with other necessary hormones. 30Acacia auriculiformis, Delonix regia, Cassia fistula, and Samanea saman all had their early seedling growth negatively affected by NaCl salinity until GA 3 was administered.The supply of GA 3 plays an essential role in protein biosynthesis because it can increase the uptake of N from the soil. 32Accumulation of organic solutes, including soluble protein and phenolics could contribute to osmotic adjustment and stabilization of membranes in plants. 28It is well-known that organic solutes can enhance plant tolerance against different stresses, including salinity, through maintaining pressure potential and membrane integrity, protection of proteins, and scavenging of free radicals. 34,35

Conclusion
In summary, salinity stress significantly inhibited the growth and development of seeds, however, the application of GA 3 can effectively ameliorate the damage caused by salt stress.This research revealed important details on the salt-stressed seeds of Acacia auriculiformis, Delonix regia, Cassia fistula, and Samanea saman, as well as the effects of growth hormone pre-treatments (GA 3 ).Primed and unprimed seeds of the listed species have different, although slightly distinct reactions to the various salinity environments.Seed priming with GA3 significantly improved the physiological parameters of Acacia auriculiformis, Delonix regia, Cassia fistula, and Samanea saman.Gibberellic acid amendment enhanced the plant growth, K+ ion concentration, while reduced the oxidative stress and Na+ ion accumulation under salinity.Up to 50 mM NaCl, priming the negative consequence of salt stress on seed germination and seedling growth of the analysed tree plants.The control seeds showed declined in physiological parameters with increasing salt stress than the primed seeds.At the highest salt levels in reductions in all seedling performances were strongly resisted.Furthermore, the roots of the studied tree plants were more affected than the shoots.The overall percentage of seeds that germinated after pre-treatment with GA3 improved the time of germination, and seedling growth performances increased.In order to lessen the negative properties of salinity stress on seed characters in vitro, this study revealed the efficiency of smearing seed priming strategies in salt-stressed conditions.However, more study is required to determine how the four primed (GA 3 ) tree seeds perform in terms of vegetative growth and yield under field conditions.
PRATICIA et al., Curr.Agri.Res., Vol.11(3) 1004-1012 (2023) Mean germination time (MGT) was designed according to 13 MGT= (∑ (n×d)/N where, n = number of seeds germinated on every day, d = number of days from the start of the germination, and N = total number of seeds germinated at the 15 days

Table 1 : Analysis of variance of growth parameters in Fabaceae seeds of treated with gibberellic acid and germinated using various concentration of NaCl solutions Source of Total Mean Seedling Shoot Root Seedling Seedlings variation Germination Germination vigour Length Length Fresh Dry Percentage Time (days) (cm) (cm) Weight(g) Weight(g)
).At 50 mM Nacl salinity level, a greater germination percentage (44.67-38.12%)was achieved in Samanea saman, followed by Acacia auriculiformis (42.10-36.80%),Delonix regia (39.15-26.35%),and the least percentage (24.78-20.22%) in Cassia fistula.Germination were significantly good up to the 50 mM Nacl salinity level in the primed seeds when compared to 100 mM Nacl.
*Significantly different at P < 0.05
of the shoot and root in four seeds.The greater decrease (for primed 8.14 % and unprimed 4.40 %) and (for primed 5.46 % and unprimed 2.32%) was pragmatic in Cassia fistula, and the lower reduction Fig. 3: