Foliar Application Of Glycinebetaine Research Articles

Efficacy of glycine betaine (G.B.), zinc (Zn), and boron (B) on some quantitative and qualitative characteristics of rainfed chickpea

To evaluate the effects of Glycine Betaine, Zinc, and Boron elements on the yield and nutritional status of rainfed Cicer arietinum, a factorial experiment, was conducted during the 2019 and 2020 cropping years in Mahabad city. The experiment followed a randomized complete block design with three replications. The experimental factors included soil application of zinc sulfate at two levels (40 kg/ha and no zinc application), foliar application of boron at three levels (no use, before, and after flowering with 3 kg per 1000 L of water), and foliar application of Glycine Betaine at three levels (no use, flowering, and after flowering with 1.88 g/L). The results indicated that the year significantly affected grain yield, biological yield, and uptake of boron and zinc. The treatments involving boron and Glycine Betaine showed an increasing effect on plant height, total chlorophyll, soluble sugar, Glycine Betaine, number of pods per plant, number of seeds per plant, 100-seed weight, grain yield, biological yield, nitrogen percentage, boron concentration, and grain protein percentage. The highest grain yield (1549.15 kg. ha−1) in the treatment without zinc application and with simultaneous application of boron and Glycine Betaine after flowering resulted in a 34.58% increase compared to the control. The foliar application of Glycine Betaine and boron in the pre-and post-flowering stages and boron in the post-flowering stage resulted in the highest grain nitrogen uptake at 60.2%. Also, the result showed that no Glycine Betaine and boron application before flowering exhibited the highest soluble sugar content.

Exogenous glycine betaine alleviates water-deficit stress in Indian pennywort (Centella asiatica) under greenhouse conditions.

Centella asiatica (Indian pennywort) is a green leafy vegetable containing centelloside' (triterpenoid), a key phytochemical component in traditional medicine. Being a glycophytic species, they exhibit decline in growth performance and yield traits when subjected to water-deficit (WD) conditions. Glycine betaine (GB) is a low molecular-weight organic metabolite that plays a crucial role in abiotic stress conditions in higher plants. The objective of this study was to investigate the potential of GB in alleviating water-deficit stress (in terms of morphological and physiological responses) in two different genotypes of Indian pennywort, "Nakhon Pathom" (NP; high centelloside-yielding genotype) and "Pathum Thani" (PT; low centelloside-yielding genotype). The genotypes of Indian pennywort were propagated by stolon cutting and transplanted into plastic bags containing 2kg of garden soil. At the flower-initiation stage (30days after transplantation), uniform plant material was treated exogenously with 0 (control), 25, and 50mMGB at 100mL per plant (one-time foliar spray) and then divided into two groups, 1) well watered (WW; irrigated daily with 400mL fresh water; 98% field capacity) and 2) water deficit (WD; withheld water for 14days; 72% field capacity). Foliar application of GB (25mM) significantly improved leaf osmotic potential in NP under WD conditions via osmotic adjustment by free proline and fructose. Differences in leaf temperature (Tleaf) between WD and WW in NP were maximized (+ 1.93°C) and the gap of Tleaf was reduced in the case of 25-50mMGB application. Similarly, crop water stress index (CWSI) in NP and PT plants under WD condition was significantly increased by 1.95- and 1.86-fold over the control, respectively; however, it was significantly decreased by exogenous GB application. Increasing Tleaf and CWSI in drought-stressed plants was closely related to stomatal closure, leading to reduced gas exchange parameters, i.e., stomatal conductance (gs), transpiration rate (E), net photosynthetic rate (Pn), and intercellular CO2 concentration (Ci), and consequently decreased plant biomass and total centelloside yield. Overall physiological, morphological, and secondary metabolite traits were enhanced in NP under WD conditions using 25mMGB exogenous application compared with the control. The study highlights the significance of GB in Indian pennywort production under limited water irrigation (water deficit) with higher vegetable yield and phytochemical stabilization.

Application of water-saving irrigation and biostimulants on the agronomic performance of maize (Zea mays)

Water deficit can limit maize yield; therefore, appropriate choices of irrigation schemes or water-saving irrigation strategies to maximize WUE are needed for sustainable agriculture in response to environmental challenges and climate change. The objectives of our study were to evaluate and compare the effects of regulated deficit irrigation (RDI) and partial root-zone drying irrigation (PRDI) schemes with various field capacity (FC) conditions on yield components, water use efficiency (WUE), photosynthesis capacity, and chlorophyll fluorescence parameters of the maize plant in a pot experiment. Moreover, we also investigated foliar application of glycine betaine (B, 50 mM) and soil-treated chitin (C, 2 g/kg) to plants against water supply limitations and highlighted their potential for the sustainable production of maize. Significantly higher plant height, cob fresh and dry weights, and total dry weight of maize were observed in RDI with the 75 % FC condition compared to the control (full irrigation with 100 % FC). PRDI treatment resulted in significantly higher economic yield, WUEyield, and WUEbiomass compared to RDI treatment. Total water used in PRDI at 50 % FC saved 72 % of water resources compared to the control. Furthermore, values for effective quantum yield (ФPSII), photochemical quenching (qP), and electron transfer rate (ETR) of maize subjected to 75 % FC were higher than under 50 % FC and the control, while maximal quantum efficiency (Fv/Fm) levels of maize were higher under 50 % FC than under 75 % FC. All agronomic traits, chlorophyll content (as SPAD value), transpiration rate, net photosynthesis value, WUEyield, and WUEbiomass of plants subjected to PRD-50 %FC with spraying B alone showed higher values compared to other chemical applications and no chemical treatment. Applying C alone to maize plants under PRDI-50 % FC increased qP and Fv/Fm compared to other chemical treatments. Evaluating water deficits with non-destructive measurements are applicable to large-scale water management of maize plants, thereby enabling scarce water resources to be conserved.

Foliar application of glycine betaine to ameliorate lead toxicity in barley plants by modulating antioxidant enzyme activity and biochemical parameters

Lead (Pb) toxicity is a major problem in agricultural soil that negatively affects plant growth and development. Glycine betaine (GB) is an effective compatible solute that resists abiotic stress and plays an important role to mitigate various stresses. The present study is the first of its kind on the application of GB to mitigate Pb toxicity on barley cultivars. To elucidate the role of GB in mitigating Pb toxicity of three concentrations (15 mM, 25 mM, and 35 mM) in two barley varieties (BH-959 and BH-946) with and without foliar application of GB (2 mM) was examined. The study found that increasing Pb concentration significantly (p < 0.05) reduced the level of primary metabolites viz. photosynthetic pigments, protein, and carbohydrates in both cultivars upto 42.4%, 38.4% and 39% respectively. However malondialdehyde content, proline content, and antioxidant enzyme activity (SOD, CAT, and POX) were found to increased significantly (p < 0.05) as compared to control treatment upto 83.4%, 83.2% and 51% respectively. In contrast, the application of GB led to significantly (p < 0.05) improved physio-biochemical parameters as well as antioxidant enzyme activity (53%) and reduced oxidative stress along with malondialdehyde content (14.42%) in both varieties. An increment in these parameters revealed that exogenous application of GB (2 mM) significantly improves Pb (up to 35 mM) toxicity in barley plants and its use may be beneficial for crops susceptible to Pb toxicity to improve growth and yield.

Using Exogenous Melatonin, Glutathione, Proline, and Glycine Betaine Treatments to Combat Abiotic Stresses in Crops.

Abiotic stresses, such as drought, salinity, heat, cold, and heavy metals, are associated with global climate change and hamper plant growth and development, affecting crop yields and quality. However, the negative effects of abiotic stresses can be mitigated through exogenous treatments using small biomolecules. For example, the foliar application of melatonin provides the following: it protects the photosynthetic apparatus; it increases the antioxidant defenses, osmoprotectant, and soluble sugar levels; it prevents tissue damage and reduces electrolyte leakage; it improves reactive oxygen species (ROS) scavenging; and it increases biomass, maintains the redox and ion homeostasis, and improves gaseous exchange. Glutathione spray upregulates the glyoxalase system, reduces methylglyoxal (MG) toxicity and oxidative stress, decreases hydrogen peroxide and malondialdehyde accumulation, improves the defense mechanisms, tissue repairs, and nitrogen fixation, and upregulates the phytochelatins. The exogenous application of proline enhances growth and other physiological characteristics, upregulates osmoprotection, protects the integrity of the plasma lemma, reduces lipid peroxidation, increases photosynthetic pigments, phenolic acids, flavonoids, and amino acids, and enhances stress tolerance, carbon fixation, and leaf nitrogen content. The foliar application of glycine betaine improves growth, upregulates osmoprotection and osmoregulation, increases relative water content, net photosynthetic rate, and catalase activity, decreases photorespiration, ion leakage, and lipid peroxidation, protects the oxygen-evolving complex, and prevents chlorosis. Chemical priming has various important advantages over transgenic technology as it is typically more affordable for farmers and safe for plants, people, and animals, while being considered environmentally acceptable. Chemical priming helps to improve the quality and quantity of the yield. This review summarizes and discusses how exogenous melatonin, glutathione, proline, and glycine betaine can help crops combat abiotic stresses.

Glycinebetaine facilitates the photosynthesis of albino tea under low temperature by regulating related gene methylation

• Glycinebetaine (GB) increased net photosynthetic rate of albino tea by 45.3% at low temperature. • GB raised the methylation of photosynthetic-related genes and chlorophyll contents. • Facilitating photosynthesis by GB was correlative to related gene methylation. • GB may play as a methyl donor for gene methylation of albino tea leaves. The frequent occurrence of adverse weather conditions in early spring caused by global climate change has seriously restricted the physiological metabolism and growth of plants in recent years. As a low temperature sensitive albino tea cultivar, white leaf No. 1 (WL-1) has been seriously affected. Regulation of DNA methylation (an epigenetic regulator) due to global climate change by glycinebetaine (GB, a bioactive methyl donor) has been often observed in animals/humans, but little is known about whether it is linked to gene methylation priming responses of plants to low temperature. Herein, the effects of foliar application of GB on photosynthesis, photosynthetic pigment synthesis and related genes methylation of WL-1 functional leaves under low temperature were investigated. Results showed that the transpiration efficiency and chlorophyll contents of WL-1 functional leaves under low temperature condition were significantly improved by the application of GB ( P < 0.05), and the net photosynthetic rate was increased by 45.3%. In addition, the application of GB promoted the methylation of most methyltransferase and demethylase genes, PSⅡ component genes and some chlorophyll synthesis genes in WL-1 functional leaves under low temperature. It was verified that the changes of photosynthetic parameters and chlorophyll content may be correlative to related gene methylation. Together, present study suggests important roles of GB in facilitating photosynthesis of albino tea functional leaves under low temperature by regulating related gene methylation.

Foliar Application of Glycine Betaine Affects Morpho-physiological, Biochemical and Fruit Quality Traits of Thomson Navel Orange Under Deficit Irrigation

Foliar Application of Glycine Betaine Affects Morpho-physiological, Biochemical and Fruit Quality Traits of Thomson Navel Orange Under Deficit Irrigation

Exogenous Glycine Betaine Reduces Drought Damage by Mediating Osmotic Adjustment and Enhancing Antioxidant Defense in Phoebe hunanensis

Drought stress negatively impacts growth and physiological processes in plants. The foliar application of glycine betaine (GB) is an effective and low-cost approach to improve the drought tolerance of trees. This study examined the effect of exogenously applied GB on the cell membrane permeability, osmotic adjustment, and antioxidant enzyme activities of Phoebe hunanensis Hand.-Mazz under drought stress. Two levels (0 and 800 mL) of water irrigation were tested under different applied GB concentrations (0, 50, 100, and 200 mM). Drought stress decreased the relative water content by 58.5% while increased the electric conductivity, malondialdehyde, proline, soluble proteins, soluble sugars, and antioxidant enzyme activities (superoxide dismutase, catalase, peroxidase) by up to 62.9%, 42.4%, 87.0%, 19.1%, 60.5%, 68.3%, 71.7%, and 83.8%, respectively, on the 25th day. The foliar application of GB, especially at 100 mM, increased the relative water content of P. hunanensis leaves under drought stress. The concentration of GB from 50 to 100 mM effectively alleviated the improvement of cell membrane permeability and inhibited the accumulation of membrane lipid peroxidation products. Under drought stress, the concentrations of proline, soluble proteins, and soluble sugars in the leaves of P. hunanensis increased as the applied GB concentration was increased and the water stress time was prolonged. Exogenously applied GB decreased oxidative stress and improved antioxidant enzyme activities as compared with treatments without GB application. Furthermore, the physiological and biochemical indexes of P. hunanensis showed a certain dose effect on exogenous GB concentration. These results suggest that GB helps maintain the drought tolerance of P. hunanensis.

Influence of foliar application of glycinebetaine on Tagetes erecta L yield cultivated under salinity conditions.

Tagetes genus of Composite family consider one of the most favorite floriculture plants. Therefore, of particular interest examine the salt tolerance of this bedding and coloring agent plant. In this research, was report the role of glycinebetaine (GB) in attenuating the adverse impacts of salt stress in African marigold plant, along with their anti-oxidative capacities and biochemical attributes. The salt stressed African marigold (100 and 150 mM NaCl) was treated with GB at 200 mM, beside untreated control plants. According to the obtained results, the growth characters were negatively in salt stressed plants but a mitigate impact of GB were observed in this respect. Obviously, the morphological as well as some physiological characters were reduced with salinity treatments while GB treatment reverses these effects. Overall, the alleviate impact of GB on the negative impact of salt stress was enhanced through improving total phenolic and antioxidant enzyme activity. Further, it is concluded that GB concentration induces the activities of antioxidative enzymes which scavenged ROS increased under saline conditions.

Role of exogenous-applied salicylic acid, zinc and glycine betaine to improve drought-tolerance in wheat during reproductive growth stages

BackgroundDrought has become a dangerous threat to reduce crop productivity throughout the world. Exogenous applications of regulators, micronutrients, and/or osmoprotectants for inducing drought-tolerance in field crops have been effectively adopted. A controlled pot study was performed to investigate the relative efficacy of salicylic acid (SA), zinc (Zn), and glycine betaine (GB) as foliar applications on the growth, tissues pigments content, relative water content (RWC), leaf gas-exchange, antioxidant enzymes activity, reactive oxygen species (ROS) accumulation, osmolytes contents, and the yield parameters of wheat plants subjected to two soil water conditions (85% field capacity: well-watered, 50% field capacity: water-deficient) during reproductive growth stages.ResultsWater deficient conditions significantly decreased the growth, yield parameters, RWC, photosynthesis pigment, and gas-exchange attributes except for intercellular CO2 concentration. However, foliar applications remarkably improved the growth and yield parameters under water deficit conditions. Under drought condition, exogenous applications of SA, Zn, and GB increased the grain yield pot− 1 by 27.99, 15.23 and 37.36%, respectively, as compared to the control treatment. Drought stress statistically increased the contents of hydrogen peroxide (H2O2), superoxide anion radical (O2•−), and malonaldehyde (MDA), and elevated the harmful oxidation to cell lipids in plants, however, they were considerably reduced by foliar applications. Foliar applications of SA, Zn, and GB decreased MDA content by 29.09, 16.64 and 26.51% under drought stress, respectively, as compared to the control treatment. Activities of all antioxidant enzymes, proline content, and soluble sugar were increased in response to foliar applications under water deficit conditions.ConclusionsOverall, foliar application of GB, SA, and Zn compounds improved the drought-tolerance in wheat by decreasing the ROS accumulation, promoting enzymatic antioxidants, and increasing osmolytes accumulation. Finally, GB treatment was most effective in thoroughly assessed parameters of wheat followed by SA and Zn applications to alleviate the adverse effects of drought stress.

Improving of Winter Cold Hardiness by Glycine Betaine in Strawberry

One of the most important problems of strawberry cultivation in temperate regions is winter cold injuries. Current study investigated impacts of foliar application of glycine betaine (GB) at 0, 0.5, 1, 2 and 4 mM concentrations on the cold hardiness of strawberry. The plants were divided into two groups: one group for evaluation of cold hardiness at temperatures of -6, -9, -12, -15 and -18 °C; and the other for study of some biochemical characteristics. Results showed that GB treatment increased soluble carbohydrate and proline concentrations in both leaf and crown tissues, total protein concentration in leaf, and relative water content in leaf as compared to those in control. Based on LT50 calculated from electrolyte leakage and tetrazolium staining test, the GB application increased cold hardiness in strawberry plant based on its concentration. The highest cold hardiness was found in the 2 mM GB concentration based on electrolyte leakage and tetrazolium staining tests at -13.3 and -15.3 °C. Meanwhile, the lowest values of cold hardiness were observed in the control treatments based on electrolyte leakage and tetrazolium staining tests at -10.2 and -11.0 °C. Significant correlations were found between soluble carbohydrate and proline concentrations in leaf and crown, and total protein concentration with LT50 calculated from electrolyte leakage and tetrazolium staining test. We conclude that application of 2 mM GBhas the capacity to increase the freezing tolerance of strawberry and could be used as a prophylactic tool to reduce winter cold injury.

Influence of foliar-applied glycinebetaine on growth, yield and some key physiological and biochemical attributes of grape (Vitis vinifera L.)

Glycinebetaine (GB) plays an imperative role to mitigate the opposing impact of several environmental stresses in various crops. The objective of this investigation was to scrutinize the response of grape (Vitis vinifera L.) to the foliar application of GB. Diverse levels of GB (0, 10, 20 and 30 mM) were applied three times with fifteen days interval to grape cv. King’s Ruby. All levels of GB improved the physiological, biochemical and growth attributes of the grape. As compared to control treatment, foliar spray of GB applied at 30 mM increased the number of leaves/vine, leaf area and number of newly emerged branches/plant by 20.55%, 12.28% and 48.13%, respectively. The pH of grape juice was decreased by increasing GB levels. However, total soluble solids, total chlorophyll contents, grape yield and photosynthesis rate was recorded maximum with foliar spray of GB applied at 30 mM. The regression model predicted that each increment in GB level enhanced the number of leaves/plant and the number of newly emerged branches/plant by 1.8 and 0.7, respectively. Thus, it is concluded that exogenous application GB applied at 30 mM might be more useful to obtain the optimum growth and quality of grapes.

Linking exogenous foliar application of glycine betaine and stomatal characteristics with salinity stress tolerance in cotton (Gossypium hirsutum L.) seedlings

BackgroundGlycine betaine (GB) plays a crucial role in plants responding to abiotic stresses. Studying the physiological response of cotton seedlings to exogenous GB under salt stress provides a reference for the application of GB to improve the resistance of cotton seedlings under salt stress. The purpose of this research is to examine the impacts of foliar-applied GB on leaf stomatal structure and characteristics, gas exchange and chlorophyll fluorescence characteristics and plant growth indicators of Gossypium hirsutum L. under NaCl stress conditions.ResultsUnder the salinity of 150 mM, the four concentrations of GB are 0, 2.5, 5, and 7.5 mM, and the control (CK) was GB-untreated non-saline. Salt stress negatively affected leaf stomata as well as gas exchange and chlorophyll fluorescence and decreased plant growth parameters of cotton seedlings. The treatment with 5 mM GB significantly increased the evolution of photosynthetic rate (Pn), transpiration rate (Tr), intracellular CO2 concentration (Ci) and stomatal conductance (gs) compared to the GB-untreated saline treatment. The Exogenous foliar-applied GB has sustainably decreased the carboxylation efficiency (Pn/Ci) and water use efficiency (WUE). The concentration of 5 mM GB leads to a significant improvement of leaf stomatal characteristics. The leaf gas exchange attributes correlated positively with stomatal density (SD), stomatal length (SL) and stomatal with (SW).ConclusionThe overall results suggested that exogenous foliar supplementation with GB can effectively alleviate the damage of salt stress to cotton seedlings. The effect of applying 5 mM GB could be an optional choice for protecting cotton seedlings from NaCl stress through promoting the stomatal functions, photosynthetic activities and growth characteristics.

Improving Albino Tea Quality by Foliar Application of Glycinebetaine as a Green Regulator under Lower Temperature Conditions

White leaf No.1 (WL-1) is a low temperature-induced albino tea cultivar, which sticks out from tea plants with rich amino acids. Because harmonization of chloroplast ultrastructure integrity and lower chlorophyll contents during the albinism processes is much crucial for WL-1 production under extreme weather conditions, we carried out a field experiment to investigate the regulating effects of exogenous glycinebetaine (GB) on the chloroplast ultrastructure and quality constituents in young leaves of WL-1 at different albinism stages. The internal structure of chloroplasts degenerated at the albinistic stage, and chlorophyll contents were significantly lower than those at pre-albinistic and regreening stages. Spraying GB regulated etioplast-chloroplast transition, significantly increased epigallocatechin gallate, theanine, and caffeine contents, and lowered chlorophyll content in albinistic young leaves of WL-1, thus improving its quality in some aspects, maintaining special leaf color, exerting flavor and umami, and improving antioxidant and refreshing effects. Foliar application of GB is an efficient technical measure in practice.

Foliar application of glycinebetaine and Zn fertilizer improves both the apparent and functional qualities of albino tea [Camellia sinensis (L.) O. Kuntze

With Zn deficiency increasing in the global population, functional plant food (including tea) can help to fill the nutrition gap that the main crops cannot meet. Glycinebetaine (GB), an important bioactive substance with a wide range of natural sources, has received limited attention towards its effects on Zn biofortification and the quality of tea. The Zn enrichment and metabolite responses of albino tea [cv. White leaf No. 1 (WL-1)] to the foliar application of GB, Zn, and their combination (Zn + GB) were investigated in a field experiment. The result indicated that the 100-buds weight, total N, Zn, Thea, and total amino acid content in the young leaves of WL-1 with Zn2 + GB2 treatment were significantly increased, whereas the Chla contents were decreased (p < 0.05). The total catechins and CAF contents of Zn2 + GB2 treatment were lower than those of other treatments, with significance (p < 0.05). Multivariate analysis and general quantitative analysis returned complementary results, revealing that Zn2 + GB2 treatment was better for the apparent and functional quality of WL-1. The more theanine and Zn, limited chlorophyll, catechin, and caffeine contributed to the quality improvement, as well as to maintaining the leaf albinistic characteristics, inhibiting astringency and bitterness, exerting flavor and umami, and improving the ultimate beneficial functions. The combined application of Zn and GB is a promising practice for Zn biofortification and for the quality improvement of tea, with spraying 750 L ha-1 of 2.0 g L-1 Zn fertilizer and 3.2 g L-1 GB mixture recommended.

Glycinebetaine-Induced Alteration in Gaseous Exchange Capacity and Osmoprotective Phenomena in Safflower (Carthamus tinctorius L.) under Water Deficit Conditions

Several inorganic and organic compounds including glycine betaine (GB) are presently being used as an exogenous application to enhance tolerance in plants to different environmental stresses. The current study assessed to what extent exogenously applied GB could improve the gaseous exchange capacity and primary and secondary metabolites in two accessions (16178 and 16180) of safflower (Carthamus tinctorius L.) plants under drought stress. Three-week-old plants of both safflower accessions were subjected to well-watered (control) or water-deficit conditions (60% field capacity (FC)). Three levels of GB (control, 50 mM and 100 mM) were sprayed to the foliage of the control and stressed plants after one month of drought application. After two weeks of foliar application of GB, gas exchange characteristics and other biochemical parameters were determined. The results showed that water deficiency markedly suppressed plant biomass, chlorophyll contents, photosynthesis rate (A), water use efficiency (A/E), stomatal conductance (gs) and relative water contents (RWC) of both accessions of safflower, while it enhanced the levels of osmolytes (GB and proline), hydrogen peroxide (H2O2) and total phenolics. Foliar application of GB was effective in enhancing the plant biomass, chlorophyll contents, gs, sub-stomatal CO2 concentration (Ci), Ci/Ca ratio, osmolytes, H2O2, ascorbic acid (AsA), total phenolics and RWC in safflower plants under water shortage. Thus, exogenous application of GB could be used as an effective strategy to improve plant growth, photosynthetic attributes and secondary metabolites in safflower plants under water deficit conditions.

Foliar-applied glycine betaine minimizes drought stress-related impact to gas exchange and the photochemical efficiency of PSII in sugarcane

Sugarcane is one of the most important crops in the world, but subject to yield losses caused by sporadic droughts during the growing season. To mitigate the effects of drought stress, different strategies have already been used, including the foliar application of glycine betaine (GB). Thus, the present study aimed to evaluate the effect of GB spraying via leaf on gas exchange, chlorophyll fluorescence and on the sugarcane water status subjected to drought stress and rewatering. The experiment was carried out in a greenhouse, using the RB92579 sugarcane variety. A randomized block design was used, in a 3 × 2 factorial scheme, composed of three GB applications (G0—without GB, G1—one application and G2—two applications) and two water treatments: irrigated (Control) and non-irrigated (Drought Stress), with subsequent rewatering. The foliar application of GB minimized the impact of drought stress on gas exchange, on the photochemical efficiency of photosystem II (PSII) and leaf tissue water status in stressed plants. In addition, it favored the energy use in the PSII and reduced photoinhibition, a fact not observed in the G0 stressed plants. Thus, it can be inferred that the GB foliar application mitigates the negative effects of drought stress on gas exchange and photochemical apparatus of PSII in young sugarcane plants.

Foliar Application of Glycine Betaine and Potassium Silicate and Its Effect on Growth Performance of Jerusalem Artichoke Grown on Calcareous Soil Under Water Stress Conditions

This investigation aims to evaluate the effect of water stress and foliar application of two different antitranspirants on growth, yield, quality and water use efficiency of Jerusalem artichoke grown a calcareous soil using drip irrigation system. For this purpose, two field experiments were carried out at soil salinity lab. Res., Agricultural Research Center, Alexandria Governorate, Egypt during the summer seasons of 2017 and 2018 using the split plot design. Jerusalem artichokeplants were irrigated by 100, 75 or 50% of water requirements (ETC). The antitranspirants included glycine betaine (200 mg/l), potassium silicate (5 cm3/l) and their combination i.e. potassium silicate (P.S) x glycine betain(G.B) in comparison with spraying distilled water as control treatment. The gained results revealed that increasing irrigation water levels from 50% up to 100% significantly (P 0.05) by the two independent variables. In addition, potassium silicate at 100% ETc; brought about the highest value for tuber yield in both seasons. Jerusalem artichoke plants irrigated with 75% of water requirements gave insignificant decrease in number of tubers/plant, tuber fresh weight and tuber yield than the treatment received 100% of water requirements. The interaction between irrigation tested levels and foliar application treatments was highly effective on tuber yield character in both seasons. The highest average values for tuber yield/feddan were recorded due to the treatments of water level of 75%ETc with spraying potassium silicate at 5cm3/ l., while the lowest mean values were achieved due to apply at 50 % irrigation level compare with control treatment. Also, the interaction between irrigation levels foliar glycine betaine, potassium silicate, and G.B. x P.S. had a significant (P<0.05) effect on K of tuber content during both seasons. The compositional elements N, P and carbohydrate content in tubers were not significantly affected by this interaction during the two seasons except inulin content during the first season only. The best results were recorded due to apply water irrigation level of 100% ETC and 75%ETC with spraying of potassium silicate at 5cm3 /l.Crop water use efficiency (CWUE) was doubled in the case of 50% ETC compared with consumptive 100% ETC. The water use efficiency increased as the irrigation level reduced.

Effects of Exogenous Application of Osmotic Adjustment Substances on Growth, Pigment Concentration, and Physiological Parameters of Dracaena sanderiana Sander under Different Levels of Salinity

We evaluated two osmotic adjustment substances (glycine betaine (GB) and glycine (G) and a combination of both glycine + glycine betaine (G + GB) using two modes of application; irrigation and foliar sprays with Dracaena sanderiana plants. The plants were grown in containers and subjected to two levels of NaCl concentrations (2.0 and 7.5 dS m−1) over 8 weeks. Growth, pigment concentrations, and physiological parameters were assessed at the end of the trial. The foliar application of GB resulted in most optimal plant growth and biomass production in the presence of NaCl. The chlorophyll and carotenoid concentrations showed different trends depending on the osmotic adjustment substance applied and the mode of application. Stomatal density and dimensions varied considerably with respect to the osmotic adjustment substance supplied. The concentration of soluble sugars in leaves did not show a clear trend under the different treatments assessed. The exogenous application of G resulted in the highest concentration of free proline and proteins in leaves. The antioxidant capacity in leaves increased with both osmotic adjustment substances, and both means of application, under low and high saline conditions. We concluded that the foliar application of GB can be recommended in order to achieve cost-effective growth of D. sanderiana under saline conditions.

EFFECT OF IRRIGATION LEVELS, SOIL CONDITIONER AND FOLIAR APPLICATION OF POTASSIUM SILICATEOR GLYCINE BETAINEON VEGETATIVE GROWTH AND CHEMICAL COMPOSITION OF GARLIC

The field experiment was carried out during the two growing seasons of 2013-2014 and 2014-2015, at the farm of Faculty of Agriculture, Ain Shams University, Shoubra El-Kheima, Egypt, to investigate the effect of irrigation after the depletion of different available soil water levels, soil conditioner, foliar application of glycine betaine and potassium silicate on vegetative growth and chemical composition of garlic (Allium sativum L.), cv. Sids-40 under water stress conditions. The experimental treatments were arranged in a split split plot design, with three replicates Irrigation levels were conducted after the depletion of 60%, 75% and 90% of available soil water in the main plots. Irrigation treatments were started six weeks from planting, soil conditioner at the rates of 2 m3/Fed and control were distributed in the sub-plots. Foliar applications of glycine betaine was used at 2 mM/Land potassium silicate was used at 0.5 g /L, after 50, 65, 80, 95, 110, 125 and 140 days respectively, from planting compared with control were devoted in the sub-sub plots. The results indicated thatthe irrigation after depletion of 60 % available soil water with applying soil conditioner and glycine betaine or potassium silicate increased the Plant lengthof garlic after 150 days from planting. Bulb diameterand nitrogen contentshowed significant increase as a result of irrigation after depletion of 60 % available soil water with applying soil conditioner in addition to the foliar application ofglycine betaine.Prolin content was significantly increased as a result of irrigation after depletion of 90 % available soil water without applying soil conditioner with the foliar application of distilled water (control).Whereas, the lowest value of Prolin content appeared with irrigation after depletion of 60 % available soil water with applying soil conditioner and foliar application of glycine betaine.Total soluble solids (TSS) andtotal Sugarsincreased significantly as a result of irrigation after depletion of 90 % available soil water without applying soil conditioner with the foliar application of glycine betaine.It was therefore concluded that vegetative growth and chemical analyses of garlic responded positively to irrigation, applying soil conditioner and foliar application of 2 mM/L glycine betaine or 0.5 g/L potassium silicate