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Báo cáo lâm nghiệp: "Water relation characteristics and photosynthesis of saline-stressed seedlings of non-halophyte species"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Water relation characteristics and photosynthesis of saline-stressed seedlings of non-halophyte species. | 372s Ann. Sci. For. 1989 46 suppl. 372S-375S Forest Tree Physiology E. Dreyer et al. eds. Elsevier INRA Water relation characteristics and photosynthesis of saline-stressed seedlings of non-halophyte species T. Suzaki H. Yahata and H. Shigenaga Laboratory of Silviculture Department of Forestry Faculty of Agriculture Kyushu University Fukuoka Japan Introduction Most plants show growth retardation at low salinity and die in high salinity. The causes are considered to be mainly water stress and or ion excess. Plants may be able to cope with an adverse water relation if they absorb salts in leaf cells to adjust osmotically. But without efficient compartmentation in vacuoles or exclusion of excessive salt in osmotic adjustment which are recognized in halophytes plants will suffer from ion excess. The objective of the present study was to examine the distribution of salts and its effect on photosynthesis for non-halophyte woody species. In addition the contribution of sodium and chloride to osmotic adjustment is discussed. Materials and Methods The seedlings of each species Osmanthus asiaticus var. aurantiacus Distylium racemo-sum Cinnamomum camphora and Euonymus japonicus were established in 1 5000 a Wagner pots. Salt treatments 0 5 10 20 and 40 artificial seawater were imposed by daily irrigation of 100 ml for 40 d. Time-course changes in photosynthetic rates were determined using an open gas-exchange system with an infrared gas analyzer. The conditions of measurement were that light intensity was 40 klx leaf temperature was 25 c and the air flow rate was 1.2 l min. Pressure-volume curves were constructed at the termination of treatment. After treatment sodium potassium and chloride concentrations were determined for leaves stem main root and fine roots. Sodium and potassium were estimated by flame photometry. Chloride was determined by silver ion titration. Results Time course changes in photosynthetic rates were shown as relative values against 0 treatment. .