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1.
Salinity stress affects many metabolic facets of plants and induces anatomical and morphological changes resulting in reduced growth and productivity. To overcome the damaging effects of salinity, different strategies of the application of nutrients with plant hormones are being adopted. The present study was carried out with an aim to find out whether application of calcium chloride (CaCl2) and gibberellic acid (GA3) could alleviate the detrimental effects of salinity stress on plant metabolism. Fifteen days old plants were supplied with (1) 0 mM NaCl + 0 mg CaCl2 kg?1 sand + 0 M GA3 (control, T0); (2) 0 mM NaCl + 10 mg CaCl2 kg?1 sand + 0 M GA3 (T1); (3) 0 mM NaCl + 0 mg CaCl2 kg?1 sand + 10?6 M GA3 (T2); (4) 150 mM NaCl + 0 mg CaCl2 kg?1 sand + 0 M GA3 (T3); (5) 150 mM NaCl + 10 mg CaCl2 kg?1 sand + 0 M GA3 (T4); (6) 150 mM NaCl + 0 mg CaCl2 kg?1 sand + 10?6 M GA3 (T5); (7) 150 mM NaCl + 10 mg CaCl2 kg?1 sand + 10?6 M GA3 (T6). To assess the response of the crop to NaCl, CaCl2 and GA3, plants were uprooted randomly at 60 days after sowing. The presence of NaCl in the growth medium decreased all the growth and physio-biochemical parameters, except electrolyte leakage, proline (Pro) and glycine betaine (GB) content, thiobarbituric acid reactive substances (TBARS), H2O2 content, activities of superoxide dismutase (SOD) and catalase (CAT) and leaf Na content, which exhibited an increase of 37.6, 29.3, 366.9, 107.5, 59.1, 17.1, 28.4 and 255.2%, respectively, compared to the control plants. However, application of CaCl2 in combination with GA3 appears to confer greater osmoprotection by the additive role with NaCl in Pro and GB accumulation. Although the activities of antioxidant enzymes (SOD, CAT and POX) were increased by salt stress, the combined application of CaCl2 and GA3 to salt-stressed plants further enhanced the activities of these enzymes by 25.1, 6.7 and 47.8%, respectively, compared to plants grown with NaCl alone. The present study showed that application of CaCl2 and GA3 alone as well as in combination mitigated the adverse effect of salinity, but combined application of these treatments proved more effective in alleviating the adverse effects of NaCl stress.  相似文献   

2.
A sandy culture experiment was conducted to investigate the effects of exogenous CaCl2 on the indole alkaloid accumulation in Catharanthus roseus under salt stress. One-month seedlings of C. roseus were treated with the different concentrations of NaCl (0, 50, and 100 mmol l? 1) and 7.5 mmol l? 1 CaCl2. The plant samples were analyzed after 7 days of the treatments. The NaCl-stressed plants showed decrease of fresh and dry weight and increase of malondialdehyde (MDA) content compared to control. Tryptophan decarboxylase (TDC) activity increased significantly under 50 mmol l? 1 NaCl without CaCl2 addition, 50 mmol l? 1 NaCl with 7.5 mmol l? 1 CaCl2, and CaCl2 treatment without NaCl addition. There was a significant increase in peroxidase activity under NaCl stress compared to control. The vindoline, catharanthine, vincristine, and vinblastine contents increased under salt stress (especially with 50 mmol l? 1 NaCl treatment with or without CaCl2). Addition of CaCl2 to NaCl-stressed plants increased biomass, TDC activity, vindoline, and catharanthine contents and lowered MDA and vincirstine contents compared to the plants without CaCl2. The plants treated with CaCl2 alone showed higher TDC activity, vindoline, catharanthine, and vinblastine content when compared to control. The results showed that exogenous CaCl2 could promote the indole alkaloid metabolism under salt stress.  相似文献   

3.
Tao Zhang  Hongbing Yang 《Phyton》2022,91(8):1643-1658
Salt stress is one of the most serious abiotic stresses limiting plant growth and development. Calcium as an essential nutrient element and important signaling molecule plays an important role in ameliorating the adverse effect of salinity on plants. This study aimed to investigate the impact of exogenous calcium on improving salt tolerance in Tartary buckwheat cultivars, cv. Xinong9920 (salt-tolerant) and cv. Xinong9909 (salt-sensitive). Four-week-old Tartary buckwheat seedlings under 100 mM NaCl stress were treated with and without exogenous calcium chloride (CaCl2), Ca2+ chelator ethylene glycol tetraacetic acid (EGTA) and Ca2+-channel blocker lanthanum chloride (LaCl3) for 10 days. Then, some important physiological and biochemical indexes were determined. The results showed that salt stress significantly reduced seedling growth, decreased photosynthetic pigments, inhibited antioxidants and antioxidant enzyme activities. However, it increased the reactive oxygen species (ROS) levels in the two Tartary buckwheat cultivars. Exogenous 10 mM CaCl2 application on salt-stressed Tartary buckwheat seedlings obviously mitigated the negative effects of NaCl stress and partially restored seedlings growth. Ca2+-treated salt-stressed seedlings diplayed a suppressed accumulation of ROS, increased the contents of total chlorophyll, soluble protein, proline and antioxidants, and elevated the activities of antioxidant enzymes compared with salt stress alone. On the contrary, the addition of 0.5 mM LaCl3 and 5 mM EGTA on salt-stressed Tartary buckwheat seedlings exhibited the opposite effects to those with CaCl2 treatment. These results indicate that exogenous Ca2+ can enhance salt stress tolerance and Ca2+ supplementation may be an effective practice to cultivate Tartary buckwheat in saline soils.  相似文献   

4.
Pot culture experiments were conducted to assess the extent of growth, photosynthetic efficiency and nitrogen assimilation of chicory (Cichorium intybus L.) as affected by NaCl and CaCl2 alone as well as in combination. Six treatments, i.e., 80 mM and 160 mM NaCl, 5 mM and 10 mM CaCl2 and 80 mM + 10 mM and 160 mM + 10 mM of NaCl + CaCl2 were given to the growing plants separately at three developmental stages, viz., the pre-flowering (30 DAS), flowering (120 DAS) and post-flowering (150 DAS) stages. Each NaCl treatment caused a significant reduction in total plant biomass, photosynthetic rate, stomatal conductance, total chlorophyll content, soluble protein content, NR activity and nitrogen content, although nitrate content increased. On the contrary CaCl2 treatment gave a favorable effect, compared to the control. The effect of combined treatments was similar to that of NaCl but less in magnitude. Thus, the application of CaCl2 may mitigate the adverse effect caused by NaCl.  相似文献   

5.
Regucalcin is a calcium regulating multifunctional protein reported to have many important functions like calcium homeostasis, anti-oxidative, anti-apoptotic and anti-cancerous functions. Although it is demonstrated as a calcium regulating protein, the calcium binding ability of regucalcin is still a controversy. The main reason for the controversy is that it lacks a typical EF hand motif which is common to most of the calcium binding proteins. Even though many studies reported regucalcin as a calcium binding protein, there are some studies reporting regucalcin as non-calcium binding also. In the present study, we investigated the calcium binding ability of recombinant buffalo regucalcin by assessing the secondary structural changes of the protein using circular dichroism spectroscopy after adding Ca2+ to the protein solution. Two types of calcium binding studies were done, one with different concentration of calcium chloride (0.5 mM CaCl2, 1 mM CaCl2, 2 mM CaCl2) and other at different time interval (no incubation and 10 min incubation) after addition of calcium chloride. Significant structural changes were observed in both studies which prove the calcium binding ability of recombinant regucalcin. A constant increase in the α-helix (1.1% with 0.5 mM CaCl2, 1.4% with 1 mM CaCl2, 3.5% with 2 mM CaCl2) and a decrease in β-sheets (78.5% with 0.5 mM CaCl2, 77.4% with 1 mM CaCl2, 75.7% with 2 mM CaCl2) were observed with the increase in calcium chloride concentration. There was a rapid increase in α-helix and decrease in β-sheets immediately after addition of calcium chloride, which subsides after 10 min incubation.  相似文献   

6.
The influence of Ca2+ salts on the resistance of red-osier dogwood (Cornus sericea) seedlings to salinity was investigated. Red-osier dogwood seedlings were exposed to 5 and 10 mM of CaCl2 or CaSO4 in the presence or absence of 50 mM NaCl for 40 days in a controlled environment. Seedlings exposed to CaCl2 and CaSO4 recovered from NaCl-induced transpiration reduction after 20 days at a concentration of 10 mM and after 30 days at a concentration of 5 mM; while in absence of additional Ca2+, the seedlings recovered only after 40 days. Addition of 10 mM Ca2+ to NaCl treatment also limited the accumulation of proline in leaf tissues and caused an increase in leaf and lateral shoot K+ content. These results suggest that 10 mM Ca2+ could alleviate, at least in part, the osmotic effect of NaCl on red-osier dogwood via control of stomatal closure. On the other hand, ion analysis showed that Ca2+ addition was able to reduce the NaCl-induced Na+ concentration only in stem tissues suggesting that Ca2+ had only a limited effect on the ionic stress. The present study also showed an unexpected NaCl-induced increase in Ca2+ content of leaves, lateral shoots and stems that was not observed in our previous hydroponics experiments and seems to be more characteristic of plants growing on sandy soils.  相似文献   

7.
The effects of sea salts, NaCl, KCl, MgCl2, MgSO4, and CaCl2, on the growth of protoplast cultures of two mangrove species, Sonneratia alba and Avicennia alba, were investigated using 96-well culture plates. Plants of these two species naturally grow at the seaward side of a mangrove forest. Cotyledon protoplasts of S. alba showed halophilic nature to NaCl, KCl, and MgCl2 at low concentrations (10–50 mM) when cultured in Murashige and Skoog’s (MS) medium containing 0.6 M mannitol. CaCl2 at a concentration higher than 25 mM was inhibitory to cell growth. On the other hand, in protoplast culture of A. alba suspension cells, which were induced from cotyledon tissues, in the modified amino acid (mAA) medium containing 1.2 M sorbitol, tolerance to NaCl, MgCl2 and MgSO4 were observed at a wide range of concentrations up to 400 mM. CaCl2 was always inhibitory for cell divisions in A. alba, but stimulatory for spherical enlargement of cells. However, no difference in cell enlargement was observed among other salts. Similarity and difference in reactivity to salts between protoplasts and suspension cells from our previous studies were discussed in relation to the site of salt tolerance or halophilic adaptation within mangrove cells. For protoplast cultures, the site(s) for response of S. alba and A. alba are located in the cytoplasm and/or the cell membrane.  相似文献   

8.
9.
A novel gene (amyZ) encoding a cold-active and salt-tolerant α-amylase (AmyZ) was cloned from marine bacterium Zunongwangia profunda (MCCC 1A01486) and the protein was expressed in Escherichia coli. The gene has a length of 1785 bp and encodes an α-amylase of 594 amino acids with an estimated molecular mass of 66 kDa by SDS-PAGE. The enzyme belongs to glycoside hydrolase family 13 and shows the highest identity (25 %) to the characterized α-amylase TVA II from thermoactinomyces vulgaris R-47. The recombinant α-amylase showed the maximum activity at 35 °C and pH 7.0, and retained about 39 % activity at 0 °C. AmyZ displayed extreme salt tolerance, with the highest activity at 1.5 M NaCl and 93 % activity even at 4 M NaCl. The catalytic efficiency (k cat/K m) of AmyZ increased from 115.51 (with 0 M NaCl) to 143.30 ml mg?1 s?1 (with 1.5 M NaCl) at 35 °C and pH 7.0, using soluble starch as substrate. Besides, the thermostability of the enzyme was significantly improved in the presence of 1.5 M NaCl or 1 mM CaCl2. AmyZ is one of the very few α-amylases that tolerate both high salinity and low temperatures, making it a potential candidate for research in basic and applied biology.  相似文献   

10.
Xanthan gum (XG) is one of the most effective thickener agents used worldwide. In foods products, one of the factors affecting its physical properties is the ionic strength of the medium. Though it is well known that XG rheological properties in aqueous media depend on both type and concentration of electrolytes, correlations between such dispersion properties and molecular aspects of dispersed XG chains are still to be more deeply studied. Thus, in the present study, aqueous XG dispersions [200 mg?(100 mL)?1] added of Na, K, Mg or Ca chlorides (ionic strength 50 mM or 100 mM) were rheologically characterized, and the corresponding results were explained based on different physicochemical analyses. Comparing to the control (unsalted XG dispersion), KCl and CaCl2 tended to produce a more drastic decrease of apparent viscosities of XG dispersions than NaCl and MgCl2. In dynamic-oscillatory assays, the predominance of elastic character over viscous character was more evident for XG dispersions containing KCl and CaCl2, in particular at frequencies > 0.1 Hz. XG dispersions containing KCl or CaCl2 also presented smaller pH and |ζ-potentials| values, as well as greater densities and average hydrodynamic diameters of dispersed XG chains, when compared to respective counterparts containing NaCl or MgCl2. As the decreasing order of the cations radii is K+?>?Ca2+ ≈ Na+?>?Mg2+, our results allowed deducing that not only the net electric charges of the cations, but also their sizes, should be considered when analyzing the effect of chloride salts on rheological properties of XG aqueous dispersions, according to the desired for this hydrocolloid (weak thickener, strong thickener or pro-gelling agent).  相似文献   

11.
An agar-degrading archaeon Halococcus sp. 197A was isolated from a solar salt sample. The agarase was purified by hydrophobic column chromatography using a column of TOYOPEARL Phenyl-650 M. The molecular mass of the purified enzyme, designated as Aga-HC, was ~55 kDa on both SDS-PAGE and gel-filtration chromatography. Aga-HC released degradation products in the order of neoagarohexose, neoagarotetraose and small quantity of neoagarobiose, indicating that Aga-HC was a β-type agarase. Aga-HC showed a salt requirement for both stability and activity, being active from 0.3 M NaCl, with maximal activity at 3.5 M NaCl. KCl supported similar activities as NaCl up to 3.5 M, and LiCl up to 2.5 M. These monovalent salts could not be substituted by 3.5 M divalent cations, CaCl2 or MgCl2. The optimal pH was 6.0. Aga-HC was thermophilic, with optimum temperature of 70 °C. Aga-HC retained approximately 90 % of the initial activity after incubation for 1 hour at 65–80 °C, and retained 50 % activity after 1 hour at 95 °C. In the presence of additional 10 mM CaCl2, approximately 17 % remaining activity was detected after 30 min at 100 °C. This is the first report on agarase purified from Archaea.  相似文献   

12.
Salinity (NaCl) is one of the major problems associated with irrigated agricultural lands, especially rice fields. Being the common inhabitants of rice fields, cyanobacteria frequently experience high concentration of NaCl which in turn causes cellular damage. Therefore, mitigation of NaCl stress in cyanobacteria, plant growth-promoting microorganisms, is of utmost importance. The present study was designed to investigate the role of calcium in the alleviation of NaCl stress-induced cellular in Synechococcus sp. PCC 7942. The cyanobacterium was subjected to sub-lethal concentration of NaCl (800 mM) with and without the supplementation of calcium (1 mM CaCl2) for 8 days. The results showed a drastic reduction in growth due to excess NaCl, but supplementation of CaCl2 reduced the salt stress damage and partially restored growth. Application of calcium increased pigment contents, photosynthetic efficiency, antioxidative enzyme activity, osmolyte contents and reduced the intracellular sodium ion concentration, MDA content, electrolyte leakage and free oxygen radical generation. Furthermore, proteins involved in photosynthesis, respiration, ATP synthesis and protein synthesis along with two hypothetical proteins were also observed to be upregulated in the cyanobacterium in presence of calcium. Furthermore, proteins related to oxidative stress defence, nitrogen metabolism, carbohydrate metabolism, fatty acid metabolism and secondary metabolism were found to be upregulated by several fold. Therefore, our study suggests that calcium suppresses salt toxicity in Synechococcus sp. PCC 7942 by restricting the entry of Na+ into the cell, increasing osmolyte production and upregulating defence-related proteins.  相似文献   

13.
Growth, osmotic adjustment, antioxidant enzyme defense and principle medicinal component bacoside A was studied in in vitro raised shoots of Bacopa monnieri under different concentrations of KCl and CaCl2 (0, 50, 100, 150 or 200 mM). Significant reduction was observed in shoot number per culture; shoot length, fresh weight, dry weight and tissue water content (TWC) when shoots were exposed to increasing KCl and CaCl2 concentrations (50–200 mM) as compared to control. Minimum damage to the membrane as assessed by malondialdehyde (MDA) content was noticed in control in contrast to sharp increase in KCl and CaCl2 stressed shoots. Higher amounts of free proline, glycine betaine and total soluble sugars (TSS) accumulated in KCl and CaCl2 exposed shoots compared to the controls. Among different concentrations of KCl and CaCl2, increasing concentration of CaCl2 showed more increase in osmolyte accumulation. Na+ content decreased with increasing concentrations of KCl and CaCl2. Accumulation of K+ increased significantly in KCl (50–100 mM) stressed shoots as compared to control, while it decreased in CaCl2 treated shoots indicating that it prevents the uptake of K+ ions. Ca2+ accumulation significantly increased with increasing concentrations of CaCl2 up to 150 mM but decreased at higher concentrations. Shoots treated with KCl and CaCl2 (0–100 mM) showed higher antioxidant enzyme (SOD, CAT, APX and GPX) activities but KCl suppressed the activities at higher concentrations. Accumulation of bacoside A was enhanced with an increase in KCl and CaCl2 concentration up to 100 mM. It appears from the data that accumulation of osmolytes, and elevated activities of antioxidant enzymes play an important role in osmotic adjustment in shoot cultures of Bacopa and the two salts tested have a positive effect on bacoside accumulation.  相似文献   

14.
The apple (Malus domestica Borkh) rootstock M 4 shoots were grown in vitro for 4 weeks on Murashige and Skoog (MS) medium containing three NaCl concentrations (35, 100 and 200 mM) in combination with two CaCl2 concentrations (5 and 10 mM). Inclusion of 10 mM CaCl2 in the medium, in the presence of 35 mM NaCl, significantly increased the number of shoots and the fresh mass compared to 5 mM CaCl2. The number of shoots, length of shoots, and the fresh mass of cultures were very low in the presence of 100 and 200 mM NaCl, independently of CaCl2 concentration of the medium. By increasing NaCl and CaCl2 concentrations in the culture medium, contents of N, Na, Cl, proline and soluble sugars in plantlets increased, whereas K, Mg, B, Zn and chlorophyll content decreased in comparison to the control.  相似文献   

15.
Two tomato (Lycopersicon esculentum Mill.) lines differing in Ca2+ use efficiency (Ca2+ use efficient line 113 and Ca2+ use inefficient line 67) were subjected to salinity treatments in two separate experiments to determine whether they differed in salt tolerance. In experiment I, three NaCl and two CaCl2 treatments were imposed. The Na+ concentrations were 1.1, 100 and 150 mM and the Ca2+ concentrations were either 1.51 or 10 mM. In experiment II, one NaCl and three Ca2+ treatments (as CaCl2 or CaSO4) were imposed. The treatments consisted of 150 mM NaCl at either 1.51 mM CaCl2, 10 mM CaCl2, or 10 mM CaSO4. Response to treatments was determined by analysis of growth parameters (shoot and root dry weights, plant height, and root length). Shoot and root dry weight, and root length were depressed as salinity increased in plants lacking additional Ca2+. No significant differences in salt tolerance were detected between the two tomato lines after 24 d of salinity treatment. An important finding of this study was that root growth and length appeared to be more sensitive to the effect of CaCI2 treatment alone and to the effects of CaCl2 × NaCl treatments. This suggests that over the long term, both root growth and root length may be more sensitive indicators of salinity effects than shoots. Supplemental CaCl2 had no ameliorative effect on NaCl stress in shoot growth. The inability of Ca2+ to counter Cl entry or toxicity may account for the lack of amelioration. Additional Ca2+ as CaSO4 improved shoot growth of plants exposed to 150 mM NaCl. In contrast, root growth and length were improved by 10 mM Ca2+ as either CaCl2 or CaSO4.  相似文献   

16.
In order to assess whether salt tolerance could be Improved In spring wheat (Triticum aestivum L.), the present study was performed by soaking the seeds of two cultlvars, namely MH-97 (salt sensitive) and Inqlab-91 (salt tolerant), for 12 h In distilled water or 100 mol/m^3 CaCl2, KCI, or NaCI. Primed seeds from each treatment group and non-primed seeds were sown In a field In which NaCI salinity of 15 dS/m was developed. Priming of seeds with CaCl2, followed by priming with KCI and NaCI, was found to be effective In alleviating the adverse effects of salt stress on both wheat cultivars In terms of shoot fresh and dry weights and grain yield. Priming with CaCl2 alleviated the adverse effects of salt stress on hormonal balance In plants of both cultlvars. In MH-97 plants, CaCl2 pretreatment considerably reduced leaf absclslc acid (ABA) concentrations and Increased leaf free salicylic acid (SA) concentrations under both saline and non-saline conditions. In contrast, In the Inqlab-91 plant, CaCl2 Increased free Indoleacetic acid (IAA) and indolebutyrlc acid (IBA) content. However, priming of seeds with CaCl2 did not alter free polyamlne levels in either cultlvar, although spermldlne levels were considerably lower In plants raised from seeds treated with CaCl2 for both cultlvars under saline conditions. Priming with KCI Increased growth In Inqlab-91 plants, but not In MH-97 plants, under saline conditions. The salinity Induced reducUon In auxins (IAA and IBA) was alleviated by NaCI priming In both cultlvars under saline conditions. However, NaCI Increased leaf free ABA content and lowered leaf SA and putresclne levels In Inqlab-91 plants under saline conditions. In conclusion, although all three priming agents (I.e. CaCl2, KCI, and NaCI) were effective In alleviating the adverse effects of salt stress on wheat plants, their effects on altering the levels of different plant hormones were different In the two cuItlvars.  相似文献   

17.
Influence of various levels of CaCl2 (0, 1, 10 and 100 mM) on exopolysaccharide production has been investigated in the cyanobacterium Anabaena 7120. At the concentration of 1 mM CaCl2, growth was found to be stimulatory while 100 mM was sub lethal for the cyanobacterial cells. Estimation of EPS content revealed that EPS production depends on the concentration of calcium ions in the immediate environment with maximum being at10 mM CaCl2. A possible involvement of alr2882 gene in the process of EPS production was also revealed through qRT-PCR. Further, FTIR-spectra marked the presence of aliphatic alkyl-group, primary amine-group, and polysaccharides along with shift in major absorption peaks suggesting that calcium levels in the external environment regulate the composition of EPS produced by Anabaena 7120. Thus, both quantity and composition of EPS is affected under different calcium chloride concentrations presenting possibilities of EPS with novel unexplored features that may offer biotechnological applications.  相似文献   

18.
Salinity tolerance of sugar beet (Beta vulgaris L.) cultivars in terms of growth, proline and soluble sugars concentrations, and Na+/K+ and Na+/Ca2+ ratios were analyzed in this study. Three-week-old seedlings of three sugar beet cultivars, ‘Gantang7’, ‘SD13829’, and ‘ST21916’, differing in salinity tolerance, were treated with 0, 50, 100, and 200 mM NaCl. Plant shoots and roots were harvested at 7 days after treatment and subjected to analysis. Low concentration of NaCl (50 mM) enhanced fresh and dry weights of shoot and root in ‘Gantang7’, whereas high one (200 mM) reduced growth in all cultivars and the less reduction was observed in ‘ST21916’. Shoot proline was strongly induced by salinity stress in both ‘Gantang7’ and ‘SD13829’, while it remained unchanged in ‘ST21916’. The addition of 50 mM NaCl significantly increased shoot soluble sugars concentrations in ‘Gantang7’ while it had no significant effects in the other two cultivars. ‘Gantang7’ also showed a higher level of root soluble sugars concentration as compared to the other two cultivars. At 50 mM NaCl, the lower shoot Na+ concentration, and the higher shoot K+ and root Ca2+ concentration in ‘Gantang7’ resulted in the lower shoot Na+/K+ and root Na+/Ca2+ ratio. However, ‘SD13829’ maintained a lower Na+/K+ ratio in both shoot and root when subjected to 200 mM NaCl treatment. According to comprehensive evaluation on salinity tolerance, it is clear that ‘Gantang7’ is more tolerant to salinity than the other two cultivars. Therefore, it is suggested that ‘Gantang7’ should be more suitable for cultivating in the arid and semi-arid irrigated regions.  相似文献   

19.
Properties of fish gelatin (FG) gel as affected by gellan (GL) at different levels (2.5–7.5% FG substitution) in combination with calcium chloride (CaCl2) at various concentrations (3–9 mM) were studied. Gel strength and hardness of FG/GL mixed gel increased as the levels of GL increased (P < 0.05). Increasing CaCl2 concentration also resulted in the increases in both gel strength and hardness of mixed gel when GL at the same level was incorporated (P < 0.05). Conversely, the increasing GL and CaCl2 levels caused a decrease in springiness but an increase in syneresis of mixed gels (P < 0.05). Gelling and melting temperatures were increased in the mixed gel as levels of GL and CaCl2 increased. L*- and b*-values of mixed gels decreased, whereas ?E*-value increased with increasing GL and CaCl2 levels (P < 0.05). Microstructure studies revealed that denser structure with smaller voids in gel network was observed in the mixed gel in the presence of CaCl2 at higher levels. However, mixed gels incorporated with GL above 5%, regardless of CaCl2 levels, yielded the lower likeness score than FG gel (control) (P < 0.05). The addition of GL at low level (2.5%) with CaCl2 (up to 6 mM) had no adverse effect on sensory property of mixed gels but could improve gelling property of FG via increasing gel strength and gelling point.  相似文献   

20.
Improvement of the host resistance by using hazard free chemical elicitors is emerging as an alternative approach in the field of plant disease management. In our present work, we have screened the efficacy and possible mechanism of abiogenic elicitors like Dipotassium hydrogen orthophosphate (K2HPO4), Oxalic acid (OA), Isonicotinic acid (INA), Salicylic acid (SA), Acetylsalicylate (AS), Arachidonic acid (AA) and Calcium chloride (CaCl2) to stimulate innate immune responses in Lycopersicum esculentum Mill. Excised tomato leaves, treated with elicitors at three different concentrations, were found to stimulate defense and antioxidative enzymes, total phenol and flavonoid content after 24 h of incubation. CaCl2 (0.5 %) followed by INA (2.5 mM) were found most effective in activation of all such defense molecules in tomato leaves. Furthermore, nitric oxide (NO), a key gaseous mediator in plant defense signaling, was also measured after subsequent elicitor application. Higher doses of elicitors showed an elevated level of reactive oxygen species (ROS) generation, enhanced lipid peroxidation rate and proline content, which indicates the extent of abiotic stress generation on the leaves. However, ROS production, lipid peroxidation rate and proline concentration remain significantly reduced as a result of CaCl2 (0.5 %) and INA (2.5 mM) application. A sharp increase of total chlorophyll content was also recorded due to treatment of CaCl2 (0.5 %). These results demonstrate the effects of different abiogenic elicitors to regulate the production of defense molecules. Results also suggest that among all such chemicals, CaCl2 (0.5 %) and INA (2.5 mM) can be used as a potential elicitor in organic farming of tomato.  相似文献   

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