[Objective] This study aimed to investigate the salt-tolerance mechanism of sweet potato.[Method]Two sweet potato varieties of Xu 25-2(salt-tolerant cultivar)and Triumph 100(salt-sensitive cultivar)were treated by sod...[Objective] This study aimed to investigate the salt-tolerance mechanism of sweet potato.[Method]Two sweet potato varieties of Xu 25-2(salt-tolerant cultivar)and Triumph 100(salt-sensitive cultivar)were treated by sodium chloride with the concentration of 0 mmol/L and 100 mmol/L.After 20 days,Na+ content and Na+/K+ ratio in the roots,shoots and leave were determined by the flame photometer,while dry weight and fresh weight of roots,shoots and leave in different varieties were also studied.[Result]The growth of two sweet potato varieties was inhibited under salt stress,so the plant became shorter,leaf and root became fewer,dry weight of roots and leave decreased,but seedlings of Xu 25-2 were inhibited slightly.Furthermore,Na+ content and Na+/K+ ratio in roots,shoots and leaves of two sweet potato varieties increased.Na+ content of salt-tolerant Xu 25-2 was low in roots,shoots and leaves,while Na+ content of salt-sensitive Triumph 100 was high in shoots and leave of seedlings,but the change range of Xu 25-2 was less than that of Triumph 100.[Conclusion]The lower Na+ content and Na+/K+ ratio in leaves under salt stress were the most important characteristics for salt-tolerance of sweet potato varieties.展开更多
The halophyte Salicornia europaea L. is a widely distributed salt-tolerant plant species that produces numerous dimorphic seeds. We studied germination and recovery in dimorphic seeds of Central Asian S. europaea unde...The halophyte Salicornia europaea L. is a widely distributed salt-tolerant plant species that produces numerous dimorphic seeds. We studied germination and recovery in dimorphic seeds of Central Asian S. europaea under various salinity conditions. We also tested the effects of various salts on Na＋ and K＋ accumulation during plant development from germination to anthesis under greenhouse conditions. We found good germination （close to control） of large seeds under NaCl between 0.5 and 2%, Na2SO4 and 2NaCl ＋ KCl ＋ CaCl between 0.5 and 3%, and 2Na2SO4 ＋ K2SO4 -- MgSO4 between 0.5 and 5%. For the small seeds, we found stimulating effects of chloride salts （both pure and mixed） under 0.5-1% concentrations, and sulfate salts under 0.5-3%. Both types of seeds showed high germination recovery potential. Salt tolerance limits of the two seed types during germination and at the later stages of development were very similar （4-5%）. During plant growth the optimal concentrations of mixed chloride and sulfate salts ranged from 0.5 to 2%. The mechanisms of salt tolerance in the two seed types of S. europaea appear to differ, but complement each other, improving overall adaptation of this species to high salinity.展开更多
Chloride ion critical content was studied under soaking and cycle of dry and wet conditions, with three electrochemical nondestructive measuring techniques, i e, half-cell potential, A C impedance, and time potential....Chloride ion critical content was studied under soaking and cycle of dry and wet conditions, with three electrochemical nondestructive measuring techniques, i e, half-cell potential, A C impedance, and time potential. The experimental results show that chloride ion critical content is primarily determined by the water cement ratio, while for the same concrete mixture the chloride ion critical content in soaking conditions is larger than that in a cycle of dry and wet conditions.展开更多
A plot culture experiment was conducted in a greenhouse at University of Zabol,Iran,to study the effects of different salinity levels and potassium supply on pearl millet.The experiment was laid out in a completely ra...A plot culture experiment was conducted in a greenhouse at University of Zabol,Iran,to study the effects of different salinity levels and potassium supply on pearl millet.The experiment was laid out in a completely randomized factorial design with three replicates.Potassium sulfate was used as the potassium source.The rates of potassium treatments were 0,100,and 200 kg ha-1.Pearl millet was subjected to different salinity levels（0,4,8,and 12 ds m-1） through addition of NaCl to irrigation water.Results showed that the increase in the salt concentration from control to 12 ds m-1 decreased grain yield（38.7%） of millet plants.In this study,we found a negative relationship between potassium and proline accumulation at vegetative（r2=-0.75＊＊） and reproductive stage（r2=-0.66＊＊） in millet plants.Salt stress remarkably elevated the activities of CAT and GPX antioxidant enzymes at vegetative and reproductive stages.Furthermore,potassium application had significant effect on grain yield and increased it about 10.6% at the highest salinity treatment（12 ds m-1）.Though,potassium treatment increased antioxidant activity in millet plants,it had no significant effect on proline content in leaves.Salinity treatment decreased potassium uptake but application potassium increased potassium content in leaves at two stages.展开更多
By micro- and macro-observations, the deterioration mechanisms of concrete under alternate action between repeated sub-high temperature/cooling by water and sodium sulfate solution attack （TW-SA） were studied; meanw...By micro- and macro-observations, the deterioration mechanisms of concrete under alternate action between repeated sub-high temperature/cooling by water and sodium sulfate solution attack （TW-SA） were studied; meanwhile, the single sodium sulfate solution attack （SA） was also done as comparison. Micro-observations included the analysis of attack products by thermal analysis method and the determination of sulfate-ion content from surface to interior by chemical titrating method （modified barium sulfate gravimetric method）. Macro-observations mainly included the mechanical behaviors such as compressive strength, splitting strength. The experimental results indicate, in both cases, the main attack product is ettringite, only in the first layer of case SA some gypsum is checked; in case SA, the sulfate ions mainly concentrate in the surface layer, so the attack is relatively mild; but in case TW-SA, the repeated sub-high temperature/cooling by water promotes the sulfate ions diffusing inwards, which leads to obvious strength degradation.展开更多
The parasitic plant Cistanche deserticola attaches to Haloxylon ammodendron, a perennial shrub with high tolerance to salinity and drought. However, little was known about the parasite-host relation between the two sp...The parasitic plant Cistanche deserticola attaches to Haloxylon ammodendron, a perennial shrub with high tolerance to salinity and drought. However, little was known about the parasite-host relation between the two species. Effects of the parasite on chlorophyll a fluorescence and nutrient accumulation in the host plant （H. am- modendron） were investigated in the Taklimakan Desert. Some photosynthetic parameters of both host and non-host H. ammodendron plants were measured by in vivo chlorophyll a fluorescence technology in the field. The assimilating branches of host and non-host plants were collected and nutrient and inorganic ion contents were analyzed. The results from field experiments showed that the infection of C. deserticola reduced the non-photochemical quenching of the variable chlorophyll fluorescence （NPQ） and the potential maximum quantum yield for primary photochemistry （Fv/Fm） of the host. Compared with non-host plants, the host H. ammodendron had low nutrient, low inorganic ion contents （Na~ and K~） and low K~/Na~ ratios in the assimilating branches. It suggested that C. deserticola infection reduced the nutrient acquisition and caused damage to the photoprotection through thermal dissipation of the energy of the photosystem II in the host, resulting in a decrease in the tolerance to salinity and high radiation. It was concluded that the attachment of the parasite plant （C. deserticola） had negative effects on the growth of its host.展开更多
基金Supported by the National Natural Science Foundation(30670177)Scientific Research Foundation for the Outstanding Young Scientist of Shangdong Province(006BS06002)National Ministry of Education Doctoral Fund(20050445003)~~
文摘[Objective] This study aimed to investigate the salt-tolerance mechanism of sweet potato.[Method]Two sweet potato varieties of Xu 25-2(salt-tolerant cultivar)and Triumph 100(salt-sensitive cultivar)were treated by sodium chloride with the concentration of 0 mmol/L and 100 mmol/L.After 20 days,Na+ content and Na+/K+ ratio in the roots,shoots and leave were determined by the flame photometer,while dry weight and fresh weight of roots,shoots and leave in different varieties were also studied.[Result]The growth of two sweet potato varieties was inhibited under salt stress,so the plant became shorter,leaf and root became fewer,dry weight of roots and leave decreased,but seedlings of Xu 25-2 were inhibited slightly.Furthermore,Na+ content and Na+/K+ ratio in roots,shoots and leaves of two sweet potato varieties increased.Na+ content of salt-tolerant Xu 25-2 was low in roots,shoots and leaves,while Na+ content of salt-sensitive Triumph 100 was high in shoots and leave of seedlings,but the change range of Xu 25-2 was less than that of Triumph 100.[Conclusion]The lower Na+ content and Na+/K+ ratio in leaves under salt stress were the most important characteristics for salt-tolerance of sweet potato varieties.
基金This study was supported by a grant from the United States Agency for International Development, Bureau for Economic Growth, Agriculture, and Trade, project number TA-MOU-03-CA23- 032.
文摘The halophyte Salicornia europaea L. is a widely distributed salt-tolerant plant species that produces numerous dimorphic seeds. We studied germination and recovery in dimorphic seeds of Central Asian S. europaea under various salinity conditions. We also tested the effects of various salts on Na＋ and K＋ accumulation during plant development from germination to anthesis under greenhouse conditions. We found good germination （close to control） of large seeds under NaCl between 0.5 and 2%, Na2SO4 and 2NaCl ＋ KCl ＋ CaCl between 0.5 and 3%, and 2Na2SO4 ＋ K2SO4 -- MgSO4 between 0.5 and 5%. For the small seeds, we found stimulating effects of chloride salts （both pure and mixed） under 0.5-1% concentrations, and sulfate salts under 0.5-3%. Both types of seeds showed high germination recovery potential. Salt tolerance limits of the two seed types during germination and at the later stages of development were very similar （4-5%）. During plant growth the optimal concentrations of mixed chloride and sulfate salts ranged from 0.5 to 2%. The mechanisms of salt tolerance in the two seed types of S. europaea appear to differ, but complement each other, improving overall adaptation of this species to high salinity.
文摘Chloride ion critical content was studied under soaking and cycle of dry and wet conditions, with three electrochemical nondestructive measuring techniques, i e, half-cell potential, A C impedance, and time potential. The experimental results show that chloride ion critical content is primarily determined by the water cement ratio, while for the same concrete mixture the chloride ion critical content in soaking conditions is larger than that in a cycle of dry and wet conditions.
文摘A plot culture experiment was conducted in a greenhouse at University of Zabol,Iran,to study the effects of different salinity levels and potassium supply on pearl millet.The experiment was laid out in a completely randomized factorial design with three replicates.Potassium sulfate was used as the potassium source.The rates of potassium treatments were 0,100,and 200 kg ha-1.Pearl millet was subjected to different salinity levels（0,4,8,and 12 ds m-1） through addition of NaCl to irrigation water.Results showed that the increase in the salt concentration from control to 12 ds m-1 decreased grain yield（38.7%） of millet plants.In this study,we found a negative relationship between potassium and proline accumulation at vegetative（r2=-0.75＊＊） and reproductive stage（r2=-0.66＊＊） in millet plants.Salt stress remarkably elevated the activities of CAT and GPX antioxidant enzymes at vegetative and reproductive stages.Furthermore,potassium application had significant effect on grain yield and increased it about 10.6% at the highest salinity treatment（12 ds m-1）.Though,potassium treatment increased antioxidant activity in millet plants,it had no significant effect on proline content in leaves.Salinity treatment decreased potassium uptake but application potassium increased potassium content in leaves at two stages.
基金Funded by the National Natural Science Foundation of China(No. 90715041)Outstanding Youth Science Fund of Henan Province(No.04120002300)
文摘By micro- and macro-observations, the deterioration mechanisms of concrete under alternate action between repeated sub-high temperature/cooling by water and sodium sulfate solution attack （TW-SA） were studied; meanwhile, the single sodium sulfate solution attack （SA） was also done as comparison. Micro-observations included the analysis of attack products by thermal analysis method and the determination of sulfate-ion content from surface to interior by chemical titrating method （modified barium sulfate gravimetric method）. Macro-observations mainly included the mechanical behaviors such as compressive strength, splitting strength. The experimental results indicate, in both cases, the main attack product is ettringite, only in the first layer of case SA some gypsum is checked; in case SA, the sulfate ions mainly concentrate in the surface layer, so the attack is relatively mild; but in case TW-SA, the repeated sub-high temperature/cooling by water promotes the sulfate ions diffusing inwards, which leads to obvious strength degradation.
基金supported by the "Western Light" Talents Training Program of Chinese Academy of Sciences (lhxz200901)
文摘The parasitic plant Cistanche deserticola attaches to Haloxylon ammodendron, a perennial shrub with high tolerance to salinity and drought. However, little was known about the parasite-host relation between the two species. Effects of the parasite on chlorophyll a fluorescence and nutrient accumulation in the host plant （H. am- modendron） were investigated in the Taklimakan Desert. Some photosynthetic parameters of both host and non-host H. ammodendron plants were measured by in vivo chlorophyll a fluorescence technology in the field. The assimilating branches of host and non-host plants were collected and nutrient and inorganic ion contents were analyzed. The results from field experiments showed that the infection of C. deserticola reduced the non-photochemical quenching of the variable chlorophyll fluorescence （NPQ） and the potential maximum quantum yield for primary photochemistry （Fv/Fm） of the host. Compared with non-host plants, the host H. ammodendron had low nutrient, low inorganic ion contents （Na~ and K~） and low K~/Na~ ratios in the assimilating branches. It suggested that C. deserticola infection reduced the nutrient acquisition and caused damage to the photoprotection through thermal dissipation of the energy of the photosystem II in the host, resulting in a decrease in the tolerance to salinity and high radiation. It was concluded that the attachment of the parasite plant （C. deserticola） had negative effects on the growth of its host.
