Ornamental characters, ion accumulation and water status in Arbutus unedo seedlings irrigated with saline water and subsequent relief and transplanting (original) (raw)
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Physiological response of ornamental tree species to induced salinity
The Indian Journal of Agricultural Sciences
An experiment was conducted to explore the possibility about saline irrigation water may be used to grow ornamental tree species in pots under sub tropical condition of Punjab for two years (2015-16). Five salinity treatments of NaCl (analytical reagent) as 0 mM, 30 mM, 40 mM, 50 mM and 60 mM were given to one year old seedlings planted in earthen pots (10”) containing soil : FYM (2:1). These concentrations were given till October. After October month, i.e. in first week of November the treatments of NaCl as 0 mM, 30 mM, 60 mM, 90 mM and 120 mM were given. The results indicated that the increased salinity concentration in Bauhinia purpurea and Milletia ovalifolia significantly reduced the total chlorophyll, carotenoid and relative water content, whereas increased the cell membrane injury during both years. In Acacia auriculiformis and Cassia fistula, total leaf chlorophyll and carotenoids were maintained or slightly increased during first year and after that decreased, whereas relat...
Plant Science, 2007
The purpose of this study was to evaluate the physiological and anatomical changes that occur in Arbutus unedo plants under saline conditions in order to understand the response of this species to salinity. A. unedo plants were grown in a greenhouse and submitted to three irrigation treatments using solutions containing 0, 52, and 105 mM NaCl with an electrical conductivity of 0.85 dS m À1 (control treatment), 5.45 dS m À1 (S.1) and 9.45 dS m À1 (S.2). After 16 weeks, the leaf water relations, root hydraulic conductivity, gas exchange, ion concentrations and leaf ultrastructure were determined. Salinity induced a significant decrease in total biomass, leaf area and plant height. The concentration of Cl À in leaves increased with increasing salinity and was higher than the corresponding concentration of Na + . Net photosynthesis (P n ) was reduced and the chloroplast ultrastructure was altered by salinity. Thylakoids were dilated and the number of plastoglobuli was greatly increased in both saline treatments compared with the control leaves. In addition, a reduction in the intercellular spaces of the lagunar mesophyll was observed in the saline treatments, affecting stomatal and mesophyll conductance to CO 2 . Root hydraulic resistance increased under saline conditions, affecting the water flow the root system. Pressure-volume analysis revealed osmotic adjustment values of 0.2 MPa at 52 mM and 0.5 MPa at 105 mM of NaCl, accompanied by 31 and 99% increases in the bulk tissue elastic modulus (e, wall rigidity) and resulting in turgor loss at the same relative water content in control and at 5.45 dS m À1 and a higher relative water content at 9.45 dS m À1 . Osmotic adjustment and a high e together are seen as an effective means of counteracting the negative effects of salinity on the water balance of A. unedo plants. #
Tolerance mechanisms of three potted ornamental plants grown under moderate salinity
Scientia Horticulturae, 2016
The scarcity of water in the Mediterranean area has frequently led to the use of saline water in order to irrigate ornamental plants in many nurseries. However, before the large-scale use of such waters, the ways in which the plants deal with the salinity need to be evaluated. Plants of Aloe vera L. Burm, Kalanchoe blossfeldiana Poelln and Gazania splendens Lem sp. were grown in pots with a mixture of sphagnum peatmoss and Perlite. In order to evaluate the effects of different levels of salinity, three treatments using different NaCl concentrations (Electrical conductivity = 2.0 (control), 4.5 and 7.5 dS m −1) were applied over a period of 60 days. At the end of the experiment, the growth, physiological parameters and mineral content of the roots and leaves were assessed for each salinity treatment. After 60 days of exposure to salinity, the total biomass of all species decreased similarly. The mineral composition of roots and leaves was clearly affected. Osmolytes, such as proline, played an important role in the osmotic adjustment in all species increasing in the roots and leaves at the higher EC i. Different mechanisms of the salt tolerance were triggered in each species. A vera plants showed Na + accumulation at the root level and a decrease in succulence index of leaves. K. blossfeldiana plants shed leaves to release Na + and G. splendens plants accumulated Cl − and Na + at the root level, secreted salt from leaves, lost salt by shedding of old leaves and increased the succulence index of remaining leaves. We concluded that the use of saline waters is feasible for growing these ornamental plants, and G. splendens seems to be particularly well adapted to salinity, a consideration that is particularly relevant in arid saline areas.
Physiological and Biochemical Responses of Plants in Saline Environment
Salinity affects plant growth and development in various ways through its impact on photosynthesis, water relations and nutrient absorption. Additionally, the biochemical composition of plants is also affected by salinity through changes in the concentration and type of proteins, amino acids, sugars and other carbohydrates. This chapter elucidates with examples the changes that occur in the plant‟s physiological functions and biochemical composition as a result of increased salinity of the plant‟s environment. It is highlighted that the fundamental mechanism of salinity‟s effects on plant function is the increase in the osmotic pressure of the plant‟s environment that inhibits the absorption of water and nutrients. Invariably, salinity inhibits photosynthesis through its effects on stomatal conductance, water and nutrient uptake and decrease in the chlorophyll concentration. Subsequently, higher levels of salinity create an excessive accumulation of salts in plant tissues that causes toxicity. Prolonged salinity will thus reduce plant growth and yield and with increasing severity of salinity, toxic levels of salts that build up in plant tissues will further aggravate the stress. Plants exhibit several mechanisms that can alleviate the deleterious effects of salinity including compartmentalization of ions, synthesis of compatible solutes, induction of plant hormones and alteration of membrane structure. Key Words: Biochemical response, plant physiology, crops, salinity, stresses
Landscape irrigation is the second largest user of reclaimed water in industrialized countries; however, its high concentration of soluble salts, especially Na + and Cl -, may induce growth reduction and leaf necrosis or bronzing in ornamental species. The present study was conducted to determine the growth and quality responses and nutritional ion imbalances of selected landscape species during the container production phase when subjected to irrigation with water of increasing NaCl + CaCl 2 concentrations. Plants of boxwood [Buxus microphylla var. japonica (Mull. Arg. ex Miq) Rehder & E.H. Wilson], escallonia (Escallonia ·exoniensis hort. Veich ex Bean), hawthorn [Raphiolepis indica (L.)
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.
HortScience
Landscape irrigation is the second largest user of reclaimed water in industrialized countries; however, its high concentration of soluble salts, especially Na+ and Cl–, may induce growth reduction and leaf necrosis or bronzing in ornamental species. The present study was conducted to determine the growth and quality responses and nutritional ion imbalances of selected landscape species during the container production phase when subjected to irrigation with water of increasing NaCl + CaCl2 concentrations. Plants of boxwood [Buxus microphylla var. japonica (Mull. Arg. ex Miq) Rehder & E.H. Wilson], escallonia (Escallonia ×exoniensis hort. Veich ex Bean), hawthorn [Raphiolepis indica (L.) Lind. Ex Ker Gawl. × ‘Montic’], hibiscus (Hibiscus rosa-sinensis L.), and juniper (Juniperus chinensis L.) were grown in a greenhouse in the Spring–Summer and in the Fall–Winter in separate experiments. Saline irrigation consisted of solutions with electrical conductivities (ECiw) of 0.6, 2, 4, 6, an...
Acta Horticulturae, 2017
High concentration of nutrients in the irrigation water of greenhouse crops is a typical phenomenon of the south Mediterranean areas and has often negative effects on plant growth and yield. High values of electrical conductivity (EC) of nutrient solution (NS) may lead to an excess of some ions and consequently to physiological and biochemical stresses resulting in reduced plant growth, leaf chlorosis and abscission. In order to evaluate the effects of increasing EC of irrigation water on plant growth and quality, a greenhouse cultivation of three containerized ornamental species (Asteriscus maritimus L., Euphorbia × lomi Rauh and Murraya paniculata (L.) Jacq.) was carried out in 7L pots containing a mixture of Mediterranean red soil, black peat and perlite (1:1:1, v/v/v). Three levels of EC (2.0, 4.0 and 6.0 dS m-1) were applied to plants by increasing macro and micronutrients content of the NS. For each species, morphological and physiological parameters were monitored during growing cycle. Asteriscus was the most tolerant of the three tested species to the high nutrients concentration of NS as best performances were recorded in plants grown with maximum EC level while lowest values were measured in the control (2.0 dS m-1). Euphorbia and Murraya presented medium tolerance to the salinity induced by major nutrients as plants of both species did not show significant differences among treatments on main morphological and physiological parameters, with no or limited reduction of ornamental traits as the EC of the NS was increased.
Response of Bedding Plants to Saline Water Irrigation
Hortscience, 2010
Bedding plants are extensively used in urban landscapes. As high-quality water supply becomes limited in many parts of the world, the use of recycled water with high salt levels for landscape irrigation is being encouraged. Therefore, information on salt tolerance of bedding plants is of increasing importance. Two experiments were conducted, one in a 25% light exclusion shadehouse in summer (Expt. 1) and the other in a greenhouse in winter (Expt. 2). Plants were irrigated with saline solution at electrical conductivities of 0.8, 2.8, 4.0, 5.1, or 7.4 dS·m -1 created by adding NaCl, MgSO 4 , and CaCl 2 to tap water to simulate the composition of local reclaimed water. In Expt. 1, shoot dry weight (DW) at the end of the experiments was reduced in all species at 7.4 dS·m -1 compared with the control (0.8 dS·m -1 ). The magnitude of reduction varied with species and cultivars. The salinity thresholds of irrigation water in which growth reduction occurred were 4.0 dS·m -1 for angelonia (Angelonia angustifolia) cultivars and ornamental pepper (Capsicum annuum) 'Calico' and 4.0 to 5.1 dS·m -1 for helenium (Helenium amarum), licorice plant (Helichrysum petiolatum), and plumbago (Plumbago auriculata). Shoot DW and growth index of ornamental pepper 'Black Pearl' and vinca (Catharanthus roseus) 'Rose' decreased linearly as salinity increased. All plants survived in Expt.
Plant Soil and Environment, 2011
In order to investigate the solutes accumulation associated with salt tolerance of rice (Oryza sativa L.), two rice genotypes including IR651 (salt-tolerant) and IR29 (salt-sensitive) were grown hydroponically in the Youshida nutrient solution. Salinity treatment was imposed 3 weeks after sowing using NaCl in two levels 0 and 100 mmol. Samples were separately collected from the youngest (sixth) leaves, leaf sheaths and roots at 72 and 240 h after salinization; then Na + , K + , Ca 2+ , Mg 2+ , P, Mn 2+ , Cland total soluble sugars concentration and Na + /K + ratio were determined. Total dry weight of both genotypes decreased with the application of NaCl. Salinity caused higher accumulation of Na + and Clin the sixth leaf and leaf sheath of IR29 than in IR651 while their concentration in root of IR651 was higher. K + concentration was decreased in the sixth leaf and leaf sheath of IR29 under NaCl stress. Reduction in Ca 2+ and Mg 2+ concentrations were observed in sixth leaves of both genotypes. P concentration was increased in leaf sheath and root of IR29 under saline conditions while it showed no changes in IR651. Our results indicated that the tolerant genotype had mechanisms to prevent high Na + and Claccumulation in the sixth leaf. High total soluble sugars concentration in shoot of IR651 is probably for adjusting osmotic potential and better water uptake under salinity. These mechanisms help plant to avoid tissue death and enable to continue its growth and development under saline conditions.