Comparative Responses of Helianthus annuus Plants and Calli Exposed to NaCl: I. Growth Rate and Osmotic Regulation in Intact Plants and Calli

Santos, Conceição; Caldeira, Gustavo

doi:10.1016/s0176-1617(99)80095-9

Cited by 41 publications

(17 citation statements)

References 25 publications

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“…On the other hand, the reverse was true for K + and Ca 2+ as well as for Na + under PEG induced osmotic stress. Such ion imbalance due to drought has already been reported in some earlier reports (Santos et al 1999;Almansouri et al 2000). It is now well established that one of the most pronounced effects of salinity (NaCl) is a consistent increase in Na + and Cl À contents along with a concomitant decrease in K + and Ca 2+ content.…”

Section: Discussionsupporting

confidence: 73%

Iso-osmotic effect of NaCl and PEG on growth, cations and free proline accumulation in callus tissue of two indica rice (Oryza sativa L.) genotypes

2007

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One-month old calli of two indica rice genotypes, i.e., Basmati-370 and Basmati-Kashmir were subjected to two iso-osmotic concentrations (À0.57 MPa and À0.74 MPa) created with 50 and 100 mol m À3 NaCl or 10 and 18% solutions of PEG-8000. Both genotypes tolerated only low levels of stress and showed severe growth suppression at À0.74 MPa. The degree of stress tolerance of both genotypes was greater for PEG induced stress than for NaCl induced stress. The relative growth rate of callus was reduced under both stresses, however, the reverse was true for callus dry weight. Sodium (Na + ) content of the callus tissue was increased only under NaCl induced stress. Salt induced stress reduced K + and Ca 2+ contents, but the PEG induced stress increased them. Higher levels of stress increased the proline content many folds with more increase being under PEG stress than that under NaCl. Water and osmotic potentials of the callus tissue decreased, whereas turgor potential increased under both abiotic stresses. Overall, Basmati-370 was more tolerant to both NaCl and PEG induced stresses than BasmatiKashmir, because of less reduction in growth and more dry weight. Moreover, Basmati-370 accumulated higher amounts of cations, free proline, and maintained maximum turgor as compared to Basmati-Kashmir. In conclusion, at cellular level, mechanism of NaCl induced osmotic stress tolerance was found to be associated with more ionic accumulation of inorganic solutes and that of PEG induced osmotic stress tolerance with the accumulation of free proline, as an important osmolyte in the cytosol.

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Section: Discussionsupporting

confidence: 73%

Iso-osmotic effect of NaCl and PEG on growth, cations and free proline accumulation in callus tissue of two indica rice (Oryza sativa L.) genotypes

2007

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“…Changes of soluble protein contents are important to understand the impact of stress on cell proteolysis and protein synthesis (Santos and Caldeira 1999). During drought periods, plants undergo many physiological changes and induce a large number of genes for adaptation (Ingram and Bartels 1996).…”

Section: Discussionmentioning

confidence: 99%

Physiological responses of different olive genotypes to drought conditions

et al. 2009

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Gas exchange rates, chlorophyll fluorescence, pressure-volume relationships, photosynthetic pigments, total soluble sugars, starch, soluble proteins and proline concentrations were investigated in five Olea europaea L. cultivars with different geographical origins (Arbequina, Blanqueta, Cobrançosa, Manzanilla and Negrinha) grown under Mediterranean field conditions. We found considerable genotypic differences among the cultivars. Comparing the diurnal gas exchange rates, we observed that Cobrançosa, Manzanilla and Negrinha had high photosynthetic rate than Arbequina and Blanqueta. The first group reveals to be better acclimated to drought conditions, and appears to employ a prodigal water-use strategy, whereas Blanqueta and Arbequina, with high water-use efficiency, appear to employ a conservative water-use strategy. The degree of midday depression in photosynthesis was genotype dependent, with a maximum in Arbequina and a minimum in Negrinha. The reductions in the photosynthetic rate were dependent from both stomatal and non-stomatal limitations. Elastic adjustment plays an important role as drought tolerance mechanism. The group of cultivars that employ a prodigal water-use strategy revealed high tissue elasticity, whereas Arbequina and Blanqueta revealed high tissue rigidity. We also identified the existence of drought tolerance mechanisms associated with soluble proteins accumulation in the foliage. The high levels of soluble proteins in Arbequina may represent an increased activity of oxidative stress defence enzymes and may also represent a reserve for post stress recovery. In all cultivars, especially in Manzanilla, free proline was accumulated in the foliage. The discussed aspects of drought stress metabolism may have an adaptative meaning, supporting the hypothesis that olive cultivars native to dry regions, such as Cobrançosa, Manzanilla and Negrinha, have more capability to acclimate to drought conditions than cultivars originated in regions with a more temperate climate, like Arbequina and Blanqueta.

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“…In T-1 seedlings, dilution effect caused by the stimulation of plant growth (Figure 1) may play an important role in the recovery of photosynthetic pigment content. Inhibition of synthesis and stimulation of decomposition possibly cause the recovery under high nitrate stress (Reddy and Vora, 1986;Santos and Caldeira, 1999). Environmental stress severely affects not only photosynthetic pigment content but chlorophyll a/b and carotenoids/chlorophyll.…”

Section: Discussionmentioning

confidence: 99%

Changes in growth and photosynthetic capacity of cucumber seedlings in response to nitrate stress

Yang

Wang

Wei

et al. 2009

Braz. J. Plant Physiol.

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The effects of three nitrate levels -14(CK), 56(T-1), and 140 mmol L -1 (T-2) -on growth and photosynthetic capacity of cucumber (Cucumis sativus L. cv. Xintaimici) seedlings grown in hydroponic culture were investigated. The results showed that at 12 d after treatment plant height, stem diameter, leaf area, and leaf number of cucumber seedlings were stimulated by 56 mmol L -1 nitrate, whereas were inhibited significantly by 140 mmol L -1 nitrate compared with CK. Short-term stimulation in photosynthetic rate occurred under T-1 treatment, and then recovered to the level of CK. Photosynthetic rate of T-2 seedlings significantly decreased over treatment course with respect to CK. Photosynthetic pigment content of T-1 and T-2 increased during the first 2 d, and gradually recovered to the level of CK thereafter. Chlorophyll a/b and carotenoids/chlorophyll of T-1 had no significant difference from CK during treatment period. During the first 4 d, there was no significant difference in chlorophyll a/b and carotenoids/chlorophyll between T-2 and CK. After 4 d, chlorophyll a/b of T-2 increased gradually, whereas carotenoids/chlorophyll decreased. Actual PSII efficiency (Φ PSII ) and photochemical quenching (qP) of T-1 had no significant difference from CK, and non-photochemical quenching (qN) was a little higher than CK after 2 d. During the first 2 d, there was little difference in Φ PSII and qP between T-2 and CK. After 2 d, both Φ PSII and qP of T-2 decreased to a great extend. A significant increase in qN of T-2 occurred over treatment course. With respect to CK, Hill reaction activity of T-1 slightly decreased, and T-2 treatment resulted in a significant decrease of Hill reaction activity. This evidence indicates that high-level nitrate stress may reduce photosynthesis through its effects not only on stomatal conductance but on the photosynthetic apparatus.

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Comparative Responses of Helianthus annuus Plants and Calli Exposed to NaCl: I. Growth Rate and Osmotic Regulation in Intact Plants and Calli

Cited by 41 publications

References 25 publications

Iso-osmotic effect of NaCl and PEG on growth, cations and free proline accumulation in callus tissue of two indica rice (Oryza sativa L.) genotypes

Iso-osmotic effect of NaCl and PEG on growth, cations and free proline accumulation in callus tissue of two indica rice (Oryza sativa L.) genotypes

Physiological responses of different olive genotypes to drought conditions

Changes in growth and photosynthetic capacity of cucumber seedlings in response to nitrate stress

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