Exogenous Application of Calcium Ameliorates Salinity Stress Tolerance of Tomato (Solanum lycopersicum L.) and Enhances Fruit Quality

Abstract

Tomato is affected by various biotic and abiotic stresses, especially salinity, which drastically hinders the growth and yield of tomato. Calcium (Ca) is a vital macronutrient which plays physiological and biochemical roles in plants. Hence, we studied the protective roles of Ca against salinity stress in tomato. There were eight treatments comprising control (nutrient solution), 5 mM Ca, 10 mM Ca, 15 mM Ca, 12 dS m−1 NaCl, 12 dS m−1 NaCl + 5 mM Ca, 12 dS m−1 NaCl + 10 mM Ca and 12 dS m−1 NaCl + 15 mM Ca, and two tomato varieties: BARI tomato-2 and Binatomato-5. Salinity significantly decreased the plant-growth and yield attributes, relative water content (RWC), photosynthetic pigments (SPAD value) and the uptake of K, Ca and Mg in leaves and roots. Salinity-induced oxidative stress was present in the form of increased Na+ ion concentration, hydrogen peroxide (H2O2) content and lipid peroxidation (MDA). Ca application reduced oxidative stress through the boosting of antioxidant enzymatic activity. Exogenous Ca application enhanced proline and glycine betaine content and reduced Na+ uptake, which resulted in the inhibition of ionic toxicity and osmotic stress, respectively. Hence, Ca application significantly increased the growth and yield attributes, RWC, SPAD value, and uptake of K, Ca and Mg. Calcium application also had a significant effect on the fruit quality of tomato and the highest total soluble solid, total sugar, reducing sugar, β-carotene, vitamin C and juice pH were found for the combined application of NaCl and Ca. Therefore, application of Ca reversed the salt-induced changes through increasing osmoprotectants, activation of antioxidants enzymes, and by optimizing mineral nutrient status.

Combined Effect of Salicylic Acid and Proline Mitigates Drought Stress in Rice (Oryza sativa L.) through the Modulation of Physiological Attributes and Antioxidant Enzymes

“…Hydrogen peroxide (H 2 O 2 ) and malondialdehyde (MDA) content were determined as described previously by Islam et al [3].…”

“…After centrifuging the homogenates at 12,000× g for 30 min at 4 • C, the supernatant was collected and used to determine different enzyme activities. Catalase (CAT, EC: 1.11.1.6) activity was determined according to the method of Islam et al [3] through monitoring the decrease in absorbance at 240 nm for 1 min caused by the decomposition of H 2 O 2 with a spectrophotometer (Shimadzu, UV-1201; 1, Nishinokyo Kuwabara-cho, Nakagyo-ku, Kyoto 604-8511, Japan). Ascorbate peroxidase (APX, EC: 1.11.1.11) activity was determined in accordance with the procedure used by Islam et al [3].…”

“…Catalase (CAT, EC: 1.11.1.6) activity was determined according to the method of Islam et al [3] through monitoring the decrease in absorbance at 240 nm for 1 min caused by the decomposition of H 2 O 2 with a spectrophotometer (Shimadzu, UV-1201; 1, Nishinokyo Kuwabara-cho, Nakagyo-ku, Kyoto 604-8511, Japan). Ascorbate peroxidase (APX, EC: 1.11.1.11) activity was determined in accordance with the procedure used by Islam et al [3]. The reaction mixture for the peroxidase contained 50 mM potassium phosphate, at pH 7.0, 0.5 mM ascorbate, 0.1 mM hydrogen peroxide and 0.1 mM ethylenediaminetetraacetic acid (EDTA) in a total volume of 1 mL.…”

“…Therefore, it is an crucial requirement to increase the rice production by several times to fulfil the food requirement for this overgrowing population. However, the availability of agricultural land is decreasing regularly due to its rapid and non-judicious use for modernization and biotic and abiotic stresses [3]. Moreover, the current status of climate change has led to higher temperatures, prolonged dry spells and severe droughts which negatively impact rice production [4,5].…”

Improving postharvest quality and vase life of cut rose flowers by pre-harvest foliar co-applications of γ-Aminobutyric Acid and calcium chloride through antioxidant contents

“…Furthermore, this essential macronutrient can modulate the activities of ACC synthase and ACC oxidase, leading to a reduction in endogenous ethylene production by the plant, thus slowing the process of senescence. A study by Islam, et al 21 showed an increase in antioxidant responses in tomato plants after the application of exogenous Ca. Due to these bene cial properties, the application of Ca salts, such as calcium chloride, calcium phosphate, calcium citrate, calcium oxide, and calcium lactate, has been reported to signi cantly prolong the vase life of cut owers in various species, including Heliconia spp 22 , Gerbera 23 , and Gladiolus 24 .…”