Does Salinity Inhibit Alfalfa Leaf Growth by Reducing Tissue Concentration of Essential Mineral Nutrients?

Animal manure and urine deposition can cause localized patches of high ionic strength (IS) soil in pastures, influencing plant production, nutritive value and sward composition. Chicory (Cichorium intybus L.) appears to thrive in high‐nutrient input situations, but no information is available on chicory response to increasing IS. In a greenhouse experiment, we evaluated the effect of rhizosphere ionic strength (0.9, 4.0, 8.0 and 12.0 dS m−1) on productivity and nutritive value of chicory. Dry matter production decreased linearly as IS increased. Shoot concentrations for Ca, Na and Cl increased as IS increased. All mineral concentrations, except Cu, were substantially higher than or equal to the highest concentrations reported for forages. At all IS, nitrate‐N and K exceeded maximum recommendation for ruminant diets. The sodium level could be high enough to reduce dry matter intake at the highest IS level. Crude protein and energy estimates indicate chicory would support production levels equivalent to those of other high‐quality forages. In vitro organic matter disappearance increased as IS increased. Chicory as a component of a forage mixture could help stabilize forage yield in pastures and also shows promise for use as a nutrient mop in feedlot areas, where excess soil nutrients are a problem.

Section: Mineral Macronutrient Relationshipssupporting

confidence: 83%

Section: Crude Proteinsupporting

confidence: 68%

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Influence of Rhizosphere Ionic Strength on Mineral Composition, Dry Matter Yield and Nutritive Value of Forage Chicory

Neel

Alloush

Belesky

et al. 2002

“…They also showed that plant survival under saline conditions is closely related to a more efficient maintenance of a low Na + : K + ratio in the upper source leaves. In another study, shoot and root concentrations of Cl − and Na + in alfalfa plants are reported to have increased significantly with increasing NaCl salinity (Esechie and Rodriguez 1999, Rogers et al. 2003).…”

Section: Introductionmentioning

confidence: 96%

Root Nitrogen Remobilization and Ion Status of Two Alfalfa (Medicago sativa L.) Cultivars in Response to Salinity Stress

Mohammadi

Poustini

Ahmadi

2008

In a pot experiment the responses of two alfalfa cultivars differing in salt tolerance were evaluated in terms of root nitrogen remobilization rates (RNRR) and their relationship with the ionic status of the plants. A split‐plot design with factorial treatments in three replications was used. Three levels of salinity stress with electrical conductivities (ECs) of 1.2, 7 and 12 ds m−1 were established in irrigation water by using tap water with and without NaCl. The average data taken from plant materials at three defoliations were used for statistical analysis. Each time, plant materials were harvested at the 10 % flowering stage and then 10 days later. From the results observed, it was found that alfalfa shoot growth is highly dependent on RNRR under salinity stress. However, the total N reserves within the roots do not appear to be a limiting factor. The high positive correlation coefficient between shoot K+/Na+ and RNRR (r = 0.77; P = 0.01) indicates that lower demands for N because of diminished metabolic activities within the shoot sink may have reduced the rates of root N utilization. Unlike in some other species, the shoot K+ concentration and contents of alfalfa plants were significantly reduced by increasing salt stress. However, a relatively suitable K+/Na+ ratio of 7.1 is maintained in the shoots at the second level of salinity, as lowering the rates of salt induced an increase in Na+ uptake (Na exclusion). The salt tolerance recognized in the Bami cultivar may be attributed to the 339 % increase in its selectivity rates of K+ over Na+ in ion transport from the soil to the shoots, as the shoot Na+ content did not increase with increasing salt levels.

“…Many studies were carried out to study the effects of temperature and salt stress on plant metabolism separately (Ashraf and Fatima 1994, Ashraf and O’Leary 1996, Cho et al. 1999, Esechie and Rodriguez 1999, Decov et al. 2000, Umezawa et al.…”

Section: Introductionmentioning

confidence: 99%

Effects of Salt Stress on Some Physiological and Photosynthetic Parameters at Three Different Temperatures in Six Soya Bean (Glycine max L. Merr.) Cultivars

Çiçek

Çakirlar

2007

IntroductionDuring their growth and development, plants are exposed to abiotic (high and low temperature, salinity, drought, radiation, etc.) and biotic (pathogen, fungus, etc.) stress factors, which decrease their yield and the quality of their products. To date, 20 %, 26 % and 15 % of suitable agricultural areas worldwide are affected by mineral, drought and temperature stresses respectively (Blum 1985, Ashraf 1994a, Flowers and Yeo 1995. In addition, there is a decay of 2 million ha of world agricultural lands to salinity each year (Kalaji and Pietkiewica 1993, Szabolcs 1994). Moreover, over 6 % of the world's total land area is affected by salinity and sodicity (Munns 2005). Plants are affected in several ways by increasing salt concentrations. It causes osmotic stress, specific ion toxicity and nutrient deficiencies, thereby affecting a range of physiological processes involved in cell metabolism (Munns 2002a).Salinity stress is often accompanied by temperature stress. Changes in ambient temperature occur more rapidly than changes in other stress factors and temperature extremes aggravate the adverse effects of other stresses, including salinity, on crop production and quality (Ashraf and Foolad 2007). It has been reported that environmental stresses lead to many social and economic problems in developing countries (Ashraf 1994a, Saiko andZonn 2000).Salt stress affects all the major processes such as photosynthesis, protein synthesis, and energy and lipid metabolism (Parida and Das 2005). Temperature and salt stresses directly or indirectly affect the photosynthetic functions by changing the structural organization and physicochemical properties of thylakoid membranes (Alia-Mohanty and Saradhi 1992, Karim et al. 1999, Lichtenthaler et al. 2005. The osmotic balance is essential for plants (Ashraf 2004). Plants have to maintain a high K + and a low Na + AbstractThe effect of NaCl ()0.1, )0.4 and )0.7 MPa) on some physiological parameters in six 23-day-old soya bean cultivars (Glycine max L. Merr. namely A 3935, CX-415, Mitchell, Nazlıcan, SA 88 and Türksoy) at 25, 30 and 35°C was investigated. Salt stress treatments caused a decline in the K + /Na + ratio, plant height, fresh and dry biomass of the shoot and an increase in the relative leakage ratio and the contents of proline and Na + at all temperatures. Effects of salt stress and temperature on Chl content, Chl a/b ratio (antenna size) and qN (heat dissipation in the antenna) varied greatly between cultivars and treatments; however, in all cases approximately the same qP value was observed. It indicates that the plants were able to maintain the balance between excitation pressure and electron transport activity. Pigment content and the quantum efficiency of photosystem II exhibited significant differences that depended on the cultivar, the salt concentration and temperature. The cultivars were relatively insensitive to salt stress at 30°C however they were very sensitive both at 25 and 35°C. Of the cultivars tested CX-415 and SA 88 were the best performers ...