[Differences of physiological responses of cucumber seedlings to NaCl and NaHCO3 stress].
By a solution culture experiment, cucumber seedlings were treated with different concentration (0, 25, 50 and 75 mmol x L(-1)) NaCl and NaHCO3, and their physiological responses were studied. The results showed that with increasing NaCl and NaHCO3 stress, the shoot and root growth, the leaf chlorophyll content and relative water content of the seedlings decreased dramatically, and the decrements were greater under NaHCO3 than under NaCl stress. The shoot Na content increased significantly with increasing NaCl and NaHCO, stress, while shoot K+ content was in adverse. At the same concentration of Na+ in culture solution, the addition of NaHCO3 induced a greater decrement of shoot K+ content, and thus, a lower shoot K+/Na+ ratio. Under NaHCO3 stress, the leaf electrolyte leakage rate and the leaf MDA, proline, and soluble sugar contents increased much greater, compared with those under NaCl stress. Under NaCl and NaHCO3 stress, the leaf superoxide dismutase (SOD), ascorbate peroxidase (APX) and dehydroascorbate reductase (DHAR) activities were induced significantly, while the leaf peroxidase (POD) activity was inhibited obviously.
Zhang
Li-ping
LP
College of of Horticulture Science and Engineering, Shandong Agricultural University Tai' an 271018, Shandong, China. lpzhang8263@163.com
Wang
Xiu-feng
XF
Shi
Qing-hua
QH
Gao
Qing-hai
QH
Liu
Ze-zhou
ZZ
D002734:Chlorophyll / Q000378:metabolism; D018553:Cucumis sativus / Q000187:drug effects / Q000254:growth & development* / Q000502:physiology; D009195:Peroxidase / Q000378:metabolism; D036226:Seedlings / Q000254:growth & development* / Q000502:physiology; D017693:Sodium Bicarbonate / Q000494:pharmacology*; D012965:Sodium Chloride / Q000494:pharmacology*; D013482:Superoxide Dismutase / Q000378:metabolism
D002734:Chlorophyll; D012965:Sodium Chloride; D017693:Sodium Bicarbonate; D009195:Peroxidase; D013482:Superoxide Dismutase