Varietal differences in physiological and biochemical responses to changes in the ionic environment (original) (raw)
Related papers
Journal of Agricultural Meteorology, 2009
In order to analyze absorption and transport of water and ions in plants affecting the salinization in the root zone through physical and physiological processes, we measured water and ion uptake by roots, transpiration rate, leaf conductance, and ion concentrations in root xylem sap and other plant tissues of corn and sunflower grown under saline conditions using a nutrient film technique system. The rate of root water uptake was lower in corn than in sunflower, where the daytime stomatal closure in response to the excessive water stress induced by the saline solution was occurred in corn but not in sunflower. NO3-, PO4 3and K were highly concentrated in the xylem sap as a result of the active and selective uptake of nutrients by roots of both corn and sunflower. Na , which is not an essential element for plant growth, was not highly concentrated in the xylem sap or plant tissues of corn because corn exhibited a poor Na absorption and transportation ability. On the other hand, sunflower had a greater ability to absorb water, Na , Mg 2 , Ca 2 , Cl-, and SO4 2-, and to transport these ions from the roots to the shoot. These differences in absorption and transport of water and ions indicate that sunflower is more salt tolerant than corn. The effects of these absorption and transport characteristics on plant growth and soil salinity should be taken into account for sustainable and effective plant production in salinized crop fields.
Annals of Botany, 2008
† Background and Aims The source of nitrogen plays an important role in salt tolerance of plants. In this study, the effects of NaCl on net uptake, accumulation and transport of ions were investigated in Nerium oleander with ammonium or nitrate as the nitrogen source in order to analyse differences in uptake and cycling of ions within plants. † Methods Plants were grown in a greenhouse in hydroponics under different salt treatments (control vs. 100 mM NaCl) with ammonium or nitrate as the nitrogen source, and changes in ion concentration in plants, xylem sap exuded from roots and stems, and phloem sap were determined. † Key Results Plant weight, leaf area and photosynthetic rate showed a higher salt tolerance of nitrate-fed plants compared with that of ammonium-fed plants. The total amount of Na þ transported in the xylem in roots, accumulated in the shoot and retranslocated in the phloem of ammonium-fed plants under salt treatment was 1. 8, 1. 9 and 2. 7 times more, respectively, than that of nitrate-treated plants. However, the amount of Na þ accumulated in roots in nitratefed plants was about 1. 5 times higher than that in ammonium-fed plants. Similarly, Cl 2 transport via the xylem to the shoot and its retranslocation via the phloem (Cl 2 cycling) were far greater with ammonium treatment than with nitrate treatment under conditions of salinity. The uptake and accumulation of K þ in shoots decreased more due to salinity in ammonium-fed plants compared with nitrate-fed plants. In contrast, K þ cycling in shoots increased due to salinity, with higher rates in the ammonium-treated plants. † Conclusions The faster growth of nitrate-fed plants under conditions of salinity was associated with a lower transport and accumulation of Na þ and Cl 2 in the shoot, whereas in ammonium-fed plants accumulation and cycling of Na þ and Cl 2 in shoots probably caused harmful effects and reduced growth of plants.
Biologia Plantarum, 1984
The effect of salts (nitrates, chlorides, and sulfates) of microelements, Cd ~+, Ni 2+, and Co 2+ and the effect of boric acid and ammonium molybdate on phosphate uptake by maize root cortex segments were tested. Higher concentration (0.1 mM) of Cu 2+ salts caused enhancement of phosphate efflux to the extent that efflux was higher than influx. Inhibitory action on phosphate uptake by maize root cortex segments was exerted by following salts: 0.01 mM Cu 2+ salts (20-30% inhibition), 0.5 mM ZnSO4 (9.7%), 0.5 and 0.05 mM ZnCl2 (34.3% and 20.8%), 0.1 mM salts of Cd 2+, Ni 2+, Co ~+ {35-78%). 1 mM FoSO4 had significant stimulatory effect (92%) on phosphate uptake. Much weaker stimulatory effect was exerted by 1 mM FeCl3 (14%), 0.05 mM ZnSOa (9.6%), 0.005 mM ZnCla and ZnSOa (8.4 and 18.5%) and 0.001 mM CdCl~ and CdSO4 (20.8 and 12.4%). All other tested salts-salts of Mn 2+ (0.1 and 0.01 mM), 0.01 and 0.001 mM salts of Co 2+ and Ni 2+, 0.001 mM salts of Cu 2 § 0.001-10 mM boric acid, and 0.001-0.1 mM ammonium molybdate left phosphate ul)take unaffected.
South African Journal of Botany, 2007
Lotus creticus (L.) is a major pastoral and forage legume in the arid climate of Tunisia where salinity is a serious production problem. A laboratory experiment was carried out to assess the physiological behaviour of two populations of Lotus creticus (Msarref (Msf) and Oued Dkouk (Odk)) in a solid substratum in the presence of salt. The tested concentrations vary from 0 to 400 mM NaCl. It has been shown that the two populations of Lotus creticus are fairly tolerant to salt at growth phase. The growth productions are recorded in absence of salt, mainly at the population Odk. The presence of salt in the medium affects growth of the whole plant for both populations. Compared to root biomass, the aerial one was more affected by salt. For all treatments, plants of the two populations remain able to produce and to allocate dry matter to the different organs. However, the salinity generated a disruption at the level of water feeding of plants of the two populations. Compared to root organ, water contents in aerial organ proved to be the least affected by salt. The survey of the relation of water content of leaves according to its production in biomass showed that the expression of growth potentialities is associated with a better leaves hydration for the population Odk. It seems then that the decrease of growth under saline stress is not associated to a water (osmotic) effect. The survey of the Na + / K + ratio showed for both studied populations an increase of Na + contents in aerial and root organs, with an excess of accumulation of these ions in the aerial organ particularly more marked at the population of Msf. In spite of the predominance of the Na + ions, the two populations, mainly Odk, remain capable to assure a K + selectivity. This selectivity is ensured mainly at the level of roots where high potassium content is recorded compared to the aerial organ. The tolerance of the two populations is probably acquired by their better faculty to assure K + selectivity and to compartmentalize Na + ions in leaves. Such a mechanism reflects probably an inclusive behaviour towards salt. This behaviour justifies the faculty of plants to maintain their growth even in very hard salinity conditions.
Ecohydrology, 2015
A glasshouse-pot trial using four levels of soil moisture (>100%, 90%, 75%, and 60% field capacity) and three levels of salinity (1.0 dSm -1 , 3.5 dSm -1 , and 6.0 dSm -1 ) was done to evaluate Na + , K + , and Claccumulation capacity and the physiological responses (net-photosynthetic rate, stomatal conductance, intercellular CO2 concentration, quantum efficiency of PSII, non-photochemical quenching) in Melilotus siculus, Tecticornia pergranulata, Cynodon dactylon , and Thinopyrum ponticum. Results reveal that the combined effect of soil water and salinity had a significant effect on Na + and Claccumulation and not on that of K + . Concentrations of Na + and Cland non-photochemical quenching increased significantly whereas, the net-photosynthetic rate (Pn), stomatal conductance (gs), and intercellular CO2 concentration decreased significantly in the tested plants, because of salinity. Salinity had no significant effect on the maximum-quantum yield and relative-water contents in shoots. Soil moisture had a significant effect on Na + , K + , and Claccumulation and the physiological responses in tested plants. Tecticornia pergranulata accumulated the highest concentrations of Na + and Cland had the lowest Pn. Cynodon dactylon accumulated the lowest concentrations of Na + and Cl -, whereas Pn was the highest. No strong positive correlation between Pn and gs was evident in tested plants. We indicate that the reduced physiological performance was due to non-stomatal activities. Na + and Claccumulation capacity in the tested plants was in the following order: T. pergranulata>M. siculus>T. ponticum>C. dactylon. Cynodon dactylon, a C4 plant, accumulated lower salt ions than the other three C3 plants.
Influence of Nitrogen Nutrition on the Ionic Balance of Maize Grown in Calcareous Soil
Journal of Soil Sciences and Agricultural Engineering (Print), 2007
The objectives of this study were to examine the influence of nitrate, ammonium and ammonium + N-Serve on ionic balance and N uptake by maize plants. Maize plant were grown in calcareous soil supplied with 100 and 200 mg N kg-1 soil in the forms of KNO3, (NH4)2SO4 (AS) and (NH4)2SO4 + Serve (AS+NS) and sampled at 30 and 60 day after sowing (DAS). Results revealed that at different growth stages, the combination of ammonium sulfate with nitrapyrine (N-Serve) gave the highest value of dry matter and N uptake as compared with other treatments. Application of N-Serve with ammonium sulfate resulted in decreasing the accumulation of NO-3 in maize leaves. NO-3 concentration was higher at 60 DAS than that found at 30 DAS and at 200 mg N/kg soil than 100 mg N/kg soil except when N-Serve was applied. Ratio of (K + /Ca 2+ + Mg 2+) was constant with all treatments which increased with ammonium sulfate + N-Serve treatments (AS + NS). Total uptake of inorganic cations and anions were determined by analysis of tissue for K + , Ca 2+ , Mg 2+ , Na + , total N, NO-3, SO = 4, PO = 4 and Cl-. Differences in total inorganic cations (C) and anions (A) in plant tissue were used to estimate total carboxylate (C-A). Internal OHgeneration resulting from excess cation uptake (net H + excretion) by the roots. The (C-A) of plant supplied 100 mg N/kg soil ranged from 85 to 116 at 30 DAS and 130 to 149 at 60 DAS. The increments in nitrogen levels tended to increase total cation uptake especially, with plants fed with ammonium + N-Serve. The increase in cation uptake was paralleled by an increase in anions uptake. The C to A uptake ratio for plants supplied with 200 mg / kg soil ranged from 2.9 to 3.4 at 30 and 60 DAS, respectively, indicating that the internal OHwas generated both by excess of cation uptake and by NO-3 and SO = 4 reduction. On a seasonal basis, only 15 % of the OHgenerated during NO-3 and SO = 4 reduction was associated with OHefflux (excess anion uptake), and 85 % was associated with carboxylate accumulation.
IONS CONCENTRATION AND THEIR RATIO IN ROOTS AND SHOOTS OF TOMATO
ABSTRACT: In order to identify the significance of Na + , Ca + , K + and Mg + concentration and ratios in plant shoots and roots as indicators for salinity tolerance, growth and biomass of seven wild, cultivated and inbred lines tomato genotypes were evaluated under stresses of saline water. The NaCl was used to prepare four treatments of irrigation water salinity,2000ppm (3.12 dsm -1 ), 4000ppm (6.25 dsm -1 2 ), 6000ppm (9.37 dsm -1 ) and 8000ppm (12.5 dsm ), while the control treatment was irrigated with tap water. The experiment was conducted in Completely Randomized design (CR) using three replications. The results indicated significant differences between tomato genotypes, irrigation water salinity levels and their interaction at all assessed growth parameters and ions concentration and their ratios in plant shoots and roots. With increasing the salinity levels, a significant reduction was observed in number of leaves/plant and plant fresh and dry weight (g) of all tested tomato genotypes. The reduction of growth parameters observed in ‘LA1421’, ‘KAU I’, ‘KAU II’, ‘F1DOM’ and ‘F1448’ depending on levels of water salinity was found to be less than those of ‘LA2711’ and ‘F1P#P2’ genotypes. Ions accumulation in plant roots and shoots was significantly increased with the increase of salinity levels in irrigation water. The accumulation of Na in ‘LA1421’, ‘F1448’ and ‘F1DOM’ roots and shoots was extremely higher than that accumulated in ‘LA2711’, ‘KAU I’, ‘KAU II’ and ‘F 1 P#P2’. The K + /Na + , K + /Ca + and Ca + /Na + values in plant roots and shoots decreased significantly with the increase of salinity stresses except K + /Ca + in ‘KAU I’ shoot and ‘KAU II’ and ‘F P#P2’ roots. The tomato genotype ‘KAU I’ and ‘KAU II’ reflected promised genetic stability as it revealed consistent tolerance behavior to the increase of salinity levels in the irrigation water through the less Na +, Ca + and Mg + 1 and high K/Na in addition to the high number of leaves/plant and dry and fresh weight. The reduction in uptake and accumulation of Na increasing K + uptake, and greater no. of leaves/plant and plant fresh and dry weight are highly recommended as indicators to salinity tolerance in tomato. + -1 and Ca + + and Ca + ,
Mechanisms of Nutrient Uptake and Assimilation Processes in Some Plants: A Review
Dutse Journal of Pure and Applied Sciences
Nutrient demands of plants are fulfilled via nutrient uptake by the roots, even though minor quantities of certain nutrients might be assimilated via leaves. For the reason that the majority of nutrients are assimilated by roots, an understanding of root morphology and cell structure is crucial in knowing this basic plant process. Nutrient achievement by plants hinges on ion applications on superficial, root assimilation capacity, and plant requirement. Movement of ion in plant cells is classified into active and passive. Ion concentrations in the cytoplasm of plant cells are frequently and considerably observed to be greater than in soil solutions. Consequently, roots ought to be able to take up ions in contrast to broadly diverse concentration gradients. Currently, two major theories of ion transport across membranes are reported in literature: carrier theory where carrier agents accountable for transferring ions from one side of membrane to the other; encounter specific io...
Alleviation of Salinity Hazards in Different Maize Genotypes Using Inorganic Ions (Ca++ and K+)
Pakistan journal of scientific and industrial research, 2020
A hydroponic experiment was conducted to evaluate and compare the efficiency of Ca and K ions and different maize genotypes with imposed salinity. Two levels of K + and Ca ++ (5 and 10 mM) each were tested on two maize genotypes (Pioneer-3335 and Syngenta-8441) under 100 mM NaCl stress. Saline treatment adversely affected the plant physiological parameters and disturbed the ionic balance and resulted in poor plant growth. However, Syngenta-8441 was more prone to salt stress as compared to Pioneer-3335. Both of the inorganic ions showed significant effects on physiological and ionic components of both genotypes. Among the inorganic ions K was found to be more efficient than Ca in improving the plant growth. Improved physiological and ionic traits were observed more significant with 10 mM K ion treatment followed by 5 mM K. Among Ca treatments higher level of Ca (10 mM) showed more significant results as compared to 5mM Ca ++. This study revealed that Ca ++ and K + both are compulsory for maintaining the crop growth because of their mutual effects under salt stress. However, the alleviative efficiency of K is far better than Calcium but its (Ca ++) role could not be neglected, while regarding genotypic differential response imposes the fact that Pioneer-3335 is more tolerant to salinity menace as compared to Syngenta-8441 but both of the genotypes were significant in their recovery from stress to applied Ca ++ and K + .
2019
Studies dealing with leaf apoplastic Na+ concentration of monocots, such as maize, under actual saline soils are scarce. Therefore, the current study was aimed to investigate the growth, total ions and leaf apoplastic Na+ concentration of salt sensitive maize plants growing in saline soils. Plants were subjected to salt stress with an electrical conductivity (EC) of 3, 8 10 and 14 dS m-1 using completely randomized design (CRD) for 3 weeks. Shoot fresh weight, plant height, leaf area and leaf length of maize plants drastically decreased when plants were exposed to increasing salt stress. We found that maize could display a steep increase in Na+ concentration in the total shoot biomass with maximum 82.3 μmol g-1 FW, when plants were subjected to highest soil salinity at 14 dS m-1. As expected, other cations i.e., K+, Ca2+ and Mg2+ decreased with increasing EC of the soil compared to Na+. Surprisingly, a maximum of 17 mM Na+ were found in the leaf apoplast of maize grown under very hi...