Ions and Organic Solutes as Implicated in the Ameliorative Effect of Exogenous Application of Calcium on Salt Stressed Tomato (Lycopersicon esculentum Mill.) Plants

Abstract

Aims: This study evaluated the role of sodium, potassium, proline and soluble sugars accumulation in the ameliorative effect of an exogenous application of calcium on the detrimental effect of salinity on tomato plants.
 Study Design: The experiment was implemented as a Completely Randomized Design (RCD) with four treatments and three replications.
 Place and Duration of Study: The experiment was realized in a green house of the Faculty of Agronomical Sciences, University of Abomey-Calavi, Benin Republic from June to July 2020. Methodology: Three weeks old plants of the tomato cultivar “Padma” was submitted in pots to four treatments comprising the control (without NaCl); salt stress (120 mM NaCl) and a combination of 120 mM NaCl and exogenous application of 40 mM CaSO4 or Ca (NO3)2 by irrigation every two days. Plants growth, sodium (Na) and potassium (K) as well as proline and soluble sugars contents of leaves and roots were determined after two weeks.
 Results: Salt effect reduced significantly plant growth at P =.05, root K content at P =.05 and leaf K/Na ratio at P =.01 whereas it increased significantly leaf Na at P =.05 and root soluble sugars content at P =.05. The application of exogenous calcium (Ca) induced a significant amelioration of plant growth at P =.01 more marked with CaSO4 than with Ca (NO3)2. This treatment induced a significant decrease at P =.01 in leaf and root Na content and a significant increase at P =.05 in root K content only for CaSO4, a significant increase at P =.01 in leaf K/Na ratio and a significant increase at P =.01 in leaf and root proline content only for Ca(NO3)2.
 Conclusion: The ameliorative effect of both forms of calcium was due mainly to sodium (Na) exclusion from leaves and potassium (K) accumulation associated to a maintain of high K/Na ratio mainly in leaves. The importance of proline accumulation as an indicator of this ameliorative effect was associated only to Ca(NO3)2.

Effect of NaCl Salt Stress on Growth, Ions and Organic Solutes Contents in a Local Cultivar Kpinman of African Eggplant (Solanum macrocarpon L) in the Republic of Benin

“…The same tendency was reported in leaves of African basil plants [13]. However, salt stress effect generally resulted in a reduction in K + content as reported in several vegetable species such as sweet basil [24], eggplant [25] ; okra [26,27] ; African basil [13] ; tomato [14] and tossa jute [28].…”

“…Na + and K + extraction and quantification were done from leaf and root dry matters as described by [14] using a flame spectrophotometer (Sherwood Model 360). Ions were expressed in mg g -1 dry matter (dm).…”

“…Proline extraction and quantification were done from leaf and root fresh matters as described by [14] using an UV-visible spectrophotometer (Jenway 7305). Proline was expressed in nmole g −1 fresh matter (fm) and soluble sugars in mg g −1 fresh matter (fm).…”

Mitigation of Salinity Stress Effects in Tomatoa (Lycopersicon esculentum Mill. ) by Using Calcium Chloride

“…To mitigate the effects of salt stress, exogenous Ca management is vital. Exogenous calcium has also been shown in several previous studies to mitigate salt stress in tomato by osmotic adjustment, an increase in antioxidant enzyme activities, the accumulation of sodium, potassium, and proline, as well as through enhancing the formation of roots and shoots [29][30][31]. It increases tolerance to salt stress by modifying growth performance, photosynthetic effectiveness, and stress-induced ROS metabolism [32,33].…”

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

“…Therefore, exogenous application of Ca is an important method to overcome the salt stress. Several previous studies also reported that exogenous calcium mitigates salt stress in tomato by osmotic adjustment, increasing antioxidant enzyme activities and the accumulation of sodium, potassium, proline and by enhancing root and shoot formation [ 27 , 28 , 29 ]. However, many aspects of exogenous Ca-mediated salt tolerance in tomato remain elusive.…”