Effectiveness of Plant Growth Regulators on Growth Attributes of Different Malaysian Rice Cultivars Primed with NaCl on Germination

Aim: Salinity is a major barrier to successful crop production. Seed priming and exogenous application of different signaling molecules can efficiently confer salinity tolerance. Wheat is a major cereal crop in the world and salinity drastically reduces the wheat seedling growth and yield. Therefore, the present study was conducted to explore the potentiality of different signaling molecules such as salicylic acid (SA) and H2O2 to alleviate the salinity-induced growth inhibition of wheat.
 Place and Duration of the Study: The study was conducted in the Department of Seed Science and Technology, Bangladesh Agricultural University, from September-October, 2021.
 Methodology: The wheat (cv. BARI-Gom 24) seeds were soaked in normal tap water (hydro-priming), 1 mM SA, 2 mM SA, 0.1 mM H2O2, and 0.15 mM H2O2 solutions for 30 minutes. The untreated seeds were used as control. Eventually, primed seeds were exposed to 150 mM NaCl in Petri dishes during germination. Primed and non-primed seedlings were grown for 15 days under 150 mM NaCl stress condition.
 Results: The result revealed that salt stress significantly reduced germination percentage (GP), germination index (GI), seed vigor index (SVI), shoot and root length. The results also exhibited that photosynthetic pigments, total chlorophyll, carotenoids, lycopene, and beta-carotene contents were significantly reduced by salt stress. Seed priming with SA and H2O2 and hydro-priming promoted the germination percentage, seedling growth (including shoot and root length), SVI, and photosynthetic pigments.
 Conclusion: Pretreatment with 1 mM SA and 0.1 mM H2O2 was observed to be relatively more efficient in conferring salinity tolerance of wheat compared with other treating conditions. Overall, this study suggests that wheat seed priming with SA and H2O2 and hydro-priming can improve salinity tolerance.
 Aim: Salinity is a major barrier to successful crop production. Seed priming and exogenous application of different signaling molecules can efficiently confer salinity tolerance. Wheat is a major cereal crop in the world and salinity drastically reduces the wheat seedling growth and yield. Therefore, the present study was conducted to explore the potentiality of different signaling molecules such as salicylic acid (SA) and H2O2 to alleviate the salinity-induced growth inhibition of wheat.
 Place and Duration of the Study: The study was conducted in the Department of Seed Science and Technology, Bangladesh Agricultural University, from September-October, 2021.
 Methodology: The wheat (cv. BARI-Gom 24) seeds were soaked in normal tap water (hydro-priming), 1 mM SA, 2 mM SA, 0.1 mM H2O2, and 0.15 mM H2O2 solutions for 30 minutes. The untreated seeds were used as control. Eventually, primed seeds were exposed to 150 mM NaCl in Petri dishes during germination. Primed and non-primed seedlings were grown for 15 days under 150 mM NaCl stress condition.
 Results: The result revealed that salt stress significantly reduced germination percentage (GP), germination index (GI), seed vigor index (SVI), shoot and root length. The results also exhibited that photosynthetic pigments, total chlorophyll, carotenoids, lycopene, and beta-carotene contents were significantly reduced by salt stress. Seed priming with SA and H2O2 and hydro-priming promoted the germination percentage, seedling growth (including shoot and root length), SVI, and photosynthetic pigments.
 Conclusion: Pretreatment with 1 mM SA and 0.1 mM H2O2 was observed to be relatively more efficient in conferring salinity tolerance of wheat compared with other treating conditions. Overall, this study suggests that wheat seed priming with SA and H2O2 and hydro-priming can improve salinity tolerance.

Coffee propagation is performed by seeding. However, germination in coffee seed is slow and uneven. Indeed, the production of plants in field is affected by environmental factors, which retards the germination rates and, in consequence, the number of plants obtained. Plant tissue culture provides the possibility of applying different growing conditions, such as different types of media and using phytoregulators, to induce a response in order to shorten zygotic embryo germination times. Therefore, due to limited understanding of growing zygotic embryos of coffee, we evaluated the effect of certain plant growth regulators on zygotic embryo germination of Coffea arabica . To study germination times, we evaluated the effects of culture media with incubation either at photoperiod or darkness and with certain plant growth regulators [gibberellic acid (GA), abscisic acid (ABA), indole-3-butyric acid (IBA), naphthalene acetic acid (NAA), kinetin (KIN) and salicylic acid (SA), at concentrations of 0.1, 1, and 10 mg l -1 each]. Zygotic embryos were cultured on Murashige and Skoog (MS), and Gamborg media at different concentrations ( 1 / 1 , ½, and ¼ of its ionic strength) under conditions of darkness and photoperiod. Germination times of zygotic embryos cultured in MS medium had a mean of 5.1 days, whereas zygotic embryos cultured in B5 medium germinated with a mean of 7.5 days. Among the plant growth regulators used, gibberellic acid at 0.1 mg l -1 proved to be the most efficient in germinating zygotic embryos, with 100% germination reached by the 5th day. Germination time of zygotic embryos was 12 days when ABA at 0.1 mg l -1 was used; however, ABA inhibited germination of embryos when it was used at concentrations of 1.0 and 10 mg l -1 since only 10% germination occurred. Regarding the germination times of zygotic embryos of coffee, the priority order of efficiency was GA > KIN > SA > IBA > NAA > ABA. Also, with the exception of SA, concentrations higher than 0.1 mg l -1 increased the zygotic embryo germination rates. Key words : Zygotic embryos, coffee, germination, phytohormones.

King sago palm or sago cycas are the other name of Kangi palm ( Cycas revoluta ) sago palm has been used as an indoor and outdoor landscape plant for centuries. The present study was conducted to estimate the effect of different priming treatments on seed germination of sago palm ( Cycas revoluta L.) in the research area of Department of Horticulture PMAS, University of Arid Agriculture Rawalpindi, Pakistan. The Experiment consisted of ten treatments; the seeds without pulp were soaked in solution of 500, 750 and 1000 ppm GA 3 and 2%, 3% and 4% solution of KNO 3 for 24 hr at room temperature. In case of hot water treatment, seeds were primed at 80 o C, 90 o C and 100 o C for 30, 20 and 10 minutes respectively. The effect of different concentrations of gibberellic acid (GA 3 ), potassium nitrate (KNO 3 ) and hot water on various parameters like germination rate, germination percentage, germination value, decayed seed percentage, time of germination, number of leaves and seedling height were studied. Significant results of germination rate (55.56 days), germination value (192.19) were achieved from 500 ppm GA 3 . Maximum germination percentage (73.33%) and number of leaves (2) were observed in KNO 3 at 2% followed by 500 ppm GA 3 . Similarly lowest decayed seed percentage (26.66%) and time of germination (59.41 days) were noted in 2% KNO 3 . The seedling height was optimum (19.33 cm) in 3% KNO 3 followed by 2% KNO 3 . Best germination results were obtained due to permeability of hard seed coat made by low concentrations of priming treatments (KNO 3 @ 3%).

Soil salinity is the major problem in arid and semi-arid regions, where rainfall is insufficient to leach salt and excess of sodium ion and it is one of the major constraints to the sustainability and expansion of rice cultivation. The depressive effect of salinity on germination could be related to a decline in endogenous levels of hormones. Presoaking seeds with optimal concentration of plant growth regulators (PGRs) has been shown to be beneficial to growth and yield of some crop species under saline conditions. It is extremely important to standardize the concentrations of PGRs as the activities changes drastically with concentrations. Therefore, we have used eight different concentrations of four PGRs along with absolute control and salinity stress treatments known to alter the germination viz., gibberellic acid, kinetin, salicylic acid and brassinosteriods and measured various physiological traits associated with germination. In case of germination percentage, brassinosteriods at 0.005 ppm was found to be the best as it registered highest germination percentage followed by gibberellic acid. Higher dry matter production was found in seeds treated with gibberellic acid and kinetin that recorded 37.4 % higher dry matter production than control. The critical enzyme in germination, a-amylase activity was higher in seeds treated with 500 ppm of gibberellic acid. These results strongly suggest that PGRs at optimum concentrations could be effectively used for improving germination associated traits undersalinity condition in rice.

To study the effects of salt stress and plant growth regulators (kinetin, gibberellic acid, potassium) on growth, yield, glycine betaine content, phosphoenolpyruvate carboxylase (PEPC) and ribulose biphosphate carboxylase (RBC) gene expression of two Libyan bread wheat varieties, a factorial design of greenhouse experiment with three replications was conducted. Results revealed that salt stress significantly reduced plant growth and productivity of both varieties. Moreover, the addition of kinetin + potassium and gibberellic acid + potassium had improved the performance of the morpho-metric parameters of both genotypes under salt stress; but the performance was more effective for kinetin treatment than for gibberellic acid. At the biochemical level, the results showed that salt stress increased glycine betaine contents in both varieties with different proportions. This increase is more elevated in the presence of kinetin + potassium than the treatment with gibberellic acid+ potassium, which showed an almost similar result as in only salt stress. At the molecular level, the effects of salt stress and plant growth regulators on the PEPC and RBC gene expression showed that the increase was significantly higher for kinetin, gibberellic acid, and salt stress when compared to the control.
 Highlights - Salt stress reduced plant growth and productivity of bread wheat varieties. - Growth regulator improved the performance of the morphometric parameters. - The performance was more effective for kinetin treatment than for gibberellic acid. - Kinetin improved the glycine betaine gene expression more than gibberellic acid. - Kinetin increased significantly the phosphoenolpyruvate carboxylase and ribulose biphosphate carboxylase gene expression.

The effects of plant growth regulators (PGRs) were studied on growth, total flavonoid, gibberellins (GA) and salicylic acid (SA) contents of Taraxacum officinale (dandelion), a widely used medicinal plant in Korea. All the four PGRs used; gibberellic acid (GA3), kinetin (Kn), salicylic acid (SA) and ethephon (2- chloroethylphosphonic acid) were applied at the rates of 0.5 and 1.0 mM. GA3 markedly enhanced fresh shoot weight, while 0.5 mM of kinetin application significantly enhanced dry root mass as compared to control. SA enhanced both shoot and root attributes, while ethephon decreased plant growth. Endogenous bioactive GA1 and GA4 content and SA content enhanced with the application of GA3, SA and kinetin, but declined with ethephon. The flavonoid content of dandelion significantly increased with SA treatment, but was not altered with the application of other PGRs. The current study demonstrated the favorable effect of GA3, kinetin and SA on growth, bioactive GAs, SA and flavonoid contents of dandelion. These investigations offered interesting information as PGRs were never tested for plant growth and development of dandelion. It also reports the presence of both early C-13 hydroxylation and non C-13 hydroxylation pathways of GA biosynthesis in dandelion for the first time.

Salinity is a dominant obstacle to the proper germination of seeds, growth of seedlings, and, consequently, the production of crops. The priming of seeds with different treating agents can efficiently impart salinity tolerance. Kidney bean is a nutritious and popular vegetable crop in the world. Literature shows that salt stress negatively disturbs the germination and growth of kidney beans. In the present research, we investigated the potentiality of salicylic acid (SA) and hydrogen peroxide (H2O2) as priming and exogenous agents to alleviate the salinity-inhibited germination and growth of kidney beans. The seeds were pretreated with SA (1 mM and 2 mM) and H2O2 (0.1 mM and 0.15 mM) and soaked in normal tap water (hydro-priming) for 60 min. In addition, for the control experiment, untreated seeds were used. Finally, primed seeds were subjected to salt stress (150 mM NaCl). Our results exhibited that salt stress considerably lowered the percentage of germination (GP), germination index (GI), seed vigor index (SVI), shoot length (SL), root length (RL), shoot–root fresh and dry biomass, and plant growth. The results also exhibited that salt stress significantly decreased the relative water content (RWC) and photosynthetic pigments such as chlorophyll, carotenoids, lycopene, and beta-carotene contents. The SA- and H2O2- and hydro-priming stimulated the GP, GI, SL, RL, SVI, and seedling growth. Data also revealed that the supplementation of SA and H2O2 enhanced RWC and photosynthetic pigments. When compared to other treatments, pretreatment with 1 mM SA was determined to be comparatively more effective at imparting the salt tolerance of kidney beans. Overall, these results, via a heatmap and principal component analysis, uncovered that priming and exogenous applications of SA and H2O2 can improve salt tolerance and enhance germination and seedling characteristics of kidney beans.

این آزمایش به منظور بررسی اثرات برخی محرک‌های رشد در بهبود شرایط رشد و نمو گل پروانش، در قالب طرح کاملا تصادفی در 5 تکرار انجام گرفت. تیمارها شامل: محلول پاشی ساده و ترکیبی، چهار ماده محرک رشد اسید اسکوربیک، اسید جیبرلیک، تیامین و بنزیل آدنین بود. نتایج حاصل از این آزمایش نشان داد که، تیمارهای به کاربرده شده بر کلیه پارامترهای اندازه گیری شده به غیر از طول عمر گل تاثیر معنی داری داشتند. با توجه به نتایج مشخص گردید که تیمار ترکیبی بنزیل آدنین به همراه تیامین و اسید اسکوربیک تعداد گل در بوته را از 72/6 به 32/16 عدد رساند و موجب افزایش 71 درصدی وزن تر بوته گردید و نیز وزن خشک بوته را بیش از دو برابر افزایش داد. همچنین تیمار بنزیل آدنین به همراه اسید جیبرلیک قطر گل را به میزان 25 درصد افزایش و تعداد شاخه جانبی و قند احیاء در تیمار ترکیبی بنزیل آدنین، تیامین و اسید اسکوربیک بیش از 100 درصد افزایش یافتند. طول شاخه جانبی در ترکیب چهارماده دوبرابر شد. نتایج نشان داد تیامین موجب افزایش 81، 88 و 59 درصدی کلروفیل a، کلروفیل b و کاروتنوئید شد.

To investigate the effect of plant growth regulators on the growth and quality of Angelica dahurica var. formosana. Five plant growth regulators: chlormequat chloride (CCC), Mepiquat chloride (PIX), Gibberellic acid (GA3), Paclobutrazol (PP333) and Maleic Hydrazide (MH) were sprayed in rosette stage, the effects of these plant growth regulators (PGRs) on the growth, yield and quality of A. dahurica var. formosanaw were observed. The biological traits were first measured and then imperatorin and isoimperatorin contents in roots were determined by HPLC. Low concentration GA3 increased the yield while not influenced the premature bolting rate and the coumarin content. Spraying of GA3 (30 mg x L(-1)) could guarantee the growth and development of A. dahurica var. formosana to have a higher yield and maintain the active ingredients content in the root as well.

Effects of plant growth regulators on the mechanical traits of perennial ryegrass (Lolium perenne L.)

The present study was performed to evaluate the effects of seed priming. This was done by soaking the seeds of two rapeseed cultivars, namely, ZY15 (tolerant to low temperature and drought) and HY49 (sensitive to low temperature and drought), for 12 h in varying solutions: distilled water, 138 mg/L salicylic acid (SA), 300 mg/L gibberellic acid (GA), 89.4 mg/L sodium nitroprusside (SNP), 3000 mg/L calcium chloride (CaCl2), and 30 mg/L abscisic acid (ABA). Primed and non-primed seeds were left to germinate at 15°C and -0.15 MPa (T15W15) and at 25°C and 0 MPa (T25W0), respectively. The results showed that SA, GA, SNP, CaCl2, and ABA significantly improved the germination potential (GP), germination rate (GR), germination index (GI), stem fresh weight (SFW), stem dry weight (SDW), root length (RL), stem length (SL), and seed vigor index (SVI) under T15W15. For ZY15 seeds under T25W0, GA, SNP, CaCl2, and ABA priming reduced the average germination time (96% after 5 days) compared to that of the control (88% after 5 days). For ZY15 seeds under T15W15, SA, SNP, CaCl2, and ABA priming, with respect to the control and water-treated groups, shortened the average germination time (92% after 5 days) compared to that of the control (80% after 5 days). For HY49 seeds under T25W0, GA, SNP, CaCl2, and ABA priming reduced the average germination time (92% after 5 days) compared to that of the control (85% after 5 days). Similarly, for HY49 seeds under T15W15, GA priming shortened the average germination time (89% after 5 days) compared to that of the control (83% after 5 days). These priming agents increased the net photosynthesis, stomatal conductivity, and transpiration rate of rape seedlings under conditions of low temperature and drought stress, while also decreasing intercellular carbon dioxide (CO2) concentrations. Additionally, SA, GA, SNP, CaCl2, and ABA increased superoxide dismutase concentrations (SOD) and ascorbic peroxidase (APX) activities of rape seedlings under stress conditions, while decreasing catalase (CAT) and peroxidase (POD) activities in ZY15 seedlings. In HY49, which is sensitive to low temperature and drought, all priming solutions, except for SNP, led to an increase in SOD activity levels and a decrease in CAT activity levels. Overall, SA, GA, SNP, and CaCl2 increased the concentrations of indoleacetic acid (IAA), GA, ABA, and cytokinin (CTK) in seedlings under stress conditions. Moreover, compared to SA, CaCl2, and ABA, GA (300 mg/L) and SNP (300 mol/L) showed improved priming effects for ZY15 and HY49 under stress conditions.

Ginger is one of the oldest and renowned commercial spices well known for its medicinal and pharmaceutical value. Land degradation, availability of the quality rhizomes and diseases are some of the challenges faced in the ginger production. Since the productivity of a plant is influenced by a complex physiological process controlled by plant growth hormone balancing systems, the application of the growth regulators can have positive effect. Manipulating the PGR combinations and concentrations can lead to better quality and productivity in ginger. Hence, an experiment was conducted to study the effect of different plant growth regulators (PGRs) on nutrient and quality parameters in the ginger variety IISR Varada. Foliar spray of PGRs with 6-benzyl adenine purine (6-BAP), cycocel (Chlormequat chloride), gibberellic acid (GA) and paclobutrazol (PBZ) with five concentrations viz., 50ppm, 100ppm, 150ppm and 200ppm were applied 4th month after planting and water spray treated as control. Nutrients composition and biochemical components were observed on 5th month after planting and oleoresin was observed in the rhizomes after harvest. The results of pooled data over two years revealed that GA at 100 ppm recorded maximum nitrogen and chlorophyll content in leaves, potassium and protein in rhizomes. Regarding the oil content, maximum was noticed in treatment 100ppm Paclobutrazol followed by GA 100ppm.

Rice seed germination and vigor are vital qualities to improve seedling growth and eventual yield. This study determined the effects of different hydropriming (0, 6, 12, or 18 h) and storage duration (0, 1, 2, and 3 mo) on the seed germination properties and seedling vigor of three irrigated varieties ‘Angelica’, ‘Tubigan 14’, ‘Tubigan 24’, and a rainfed variety ‘Sahod Ulan 9’. The seed quality and germination responses after hydropriming were evaluated every month during storage in ambient conditions (28 ± 2 °C; 85 ± 5% RH) for 3 mo. ‘Sahod Ulan 9’ showed tolerance to low moisture content (MC), higher germination percentage (GP) and germination index (GI), plus faster mean germination time (MGT) and days to radicle emergence (DRE); it also produced seedlings with longer shoots compared to ‘Angelica’, ‘Tubigan 14’, ‘Tubigan 24’. On the other hand, the irrigated varieties showed a higher seed vigor index (SVI) because of their high GP plus longer roots and seedlings. Hydropriming seeds for 6 or 12 h maintained a lower MC, which resulted in higher GP, GI, and SVI; fastest MGT and DRE; and longer shoot, root, and seedling. This study suggests that hydropriming rice seeds of these varieties for 6 h is sufficient to improve germination and vigor. The results suggest that hydropriming rice seeds for 6 h is sufficient to boost the rice germination and vigor of the four rice varieties tested, especially ‘Sahod Ulan 9’. Storage in ambient room conditions is suggested to be limited to only 1 mo after hydropriming as the germination responses decline thereafter. Moreover, the interaction effects of genotype, hydropriming duration, and storage time were found in GP; GI; DRE; root, shoot, and seedling lengths; and SVI.

An experiment was conducted to study the impact of seed soaking with plant growth regulators (gibberellic acid, indole acetic acid, kinetin, salicylic acid and ascorbic acid) and nutrients (potassium chloride and calcium chloride) on mung bean (Vigna radiata L.) variety Co (Gg) 8 under salt stress condition. The seed and seedling growth under normal and saline (150 mM NaCl) conditions were studied to determine their usefulness in increasing relative salt tolerance by using PGRs and nutrients. Under salt stress, seedling characters were significantly affected compared to normal condition. Seed treatments with gibberellic acid (1mM), salicylic acid (2 mM), ascorbic acid (50 ppm) and kinetin (50 ppm) drastically increased the morphological and biochemical parameters of seedling under saline conditions. All pre-soaking seed treatments increased the germination percentage, shoot and root length, vigour index and stress tolerance index over control. Among the treatments, gibberellic acid, salicylic acid and ascorbic acid showed their supremacy compared to other treatments. Na+ / K+ ratio was decreased by gibberellic acid, CaCl2 (0.5%) and KCl (1%) treatments. It is concluded that treatments with hormones and nutrients have reduced the severity of the salinity effect and the amelioration was observed in all the treatments compare to control. Gibberellic acid and salicylic acid and ascorbic acid showed best results on seedling growth and biochemical characters whereas seed soaking with gibberellic acid, CaCl2 (0.5%) and KCl (1%) were showed its effect on decreased Na+ / K+ ratio under present experimental material and saline conditions.Keywords: Catalase, Mung bean, Na+/K+, Nutrients, PGRs, Salinity, STI, Vigour Index.

Tulip (Tulipa gesneriana L.) is an important and highly valuable flower of the cut flower industry. The most critical step in its cultivation is to break dormancy in order to initiate the growth, especially in tropical and sub-tropical areas of the world. Therefore, the current research was conducted to break bulb dormancy and foster the growth of tulip in Potohar region with the help of different primers. The objective of this study was the selection of best primer at appropriate concentration level to enhance growth, yield and vase life of the flower. Tulip bulbs were treated with different primers: T0 (distilled water), T1 (chitosan @ 5 g/L), T2 (gibberellic acid @ 0.15 g/L), T3 (humic acid 160 g/L), T4 (imidacloprid 19 g/L) and T5 (salicylic acid 0.1 g/L) for 24 hours, respectively. The experiment was laid out using Complete Randomized Design (CRD) with three replications. Statistical results revealed that characteristics including early germination, plant height, number of leaves, stalk length, fresh and dry weight of flower, weight of bulbs, diameter of bulbs and number of daughter bulbs were significantly increased in T2. Whereas, leaf area, diameter of stem and flower was maximum in T0. Plants under T3 showed an increase in chlorophyll content of leaves. While floral characteristics like early formation and opening of flower bud, more number of flowers and vase life were improved in T1. Thus, statistical results showed that priming can effectively help to improve morpho-physiological attributes of tulip.