Study On The Physiological Characteristic Of Five Dwarf Ornamental Bamboos Under NaCl Stress

In this paper, the author had investigated the effects of salt stress on the physiological and biochemical indicators of five species of bamboos including Pleioblastus kongosonensis f. aureo-stratus Muroi et Y. Tanaka(e), Shibataea chinensis Nakai ,Sasa pygmaea (Miq.) E.G.Camus,Peiobastus fortunei (Van Houtee) Fiori and Pleioblastus argenteostriatus Naksi and appraised the comprehensive salt tolerant ability of these bamboos.The main results were described as follows: 1.The fresh weights decreased with the increasing of salinity, the difference of which were noticeable among different NaCl salinity by variance analysis. The growth rate of fresh weight of bamboos decreaced with the prolongation of the time of salt stress. 2.The Na⁺ and Ca²⁺contents and the ratios of Na⁺ to K⁺ of root,rhizome,culm and leaf of bamboos increased while the K+ contents decreased with the increasing of salinity. 3.The survival rates of bamboos decreased with the increasing of NaCl salinity. 4.The free proline contents of leaves of bamboos increased with the increasing of the salinity and with the prolongation of the time of salt stress. 5.The MDA contents of bamboos increased with the increasing salinity and with the prolongation of time of salt stress. 6.The effects of salt stress on the chlorophyll contents were various in different periods. Generally, the chlorophyll a, b and chlorophyll contents (a+b) of bamboos all decreased with the increasing of salt contents and the prolongation of NaCl stress, the ratios of the chlorophyll a to b fluctuated between 2.0 and 4.0. 7.Under the NaCl stress , with the increasing of salinity, the net photosynthetic rate , the stomatal conductance to H2O,the inter-celluar and transpiration rate decreased while vapor pressure deficit based on Leaf temperature increased. 8.The comprehensive salt tolerant ability of bamboos was analysed by both subordinate function method and coordinate comprehensive appraisal method. According the former, the results was that the rank of salt tolerant ability of five bamboos was that Pleioblastus kongosonensis f. aureo-stratus > Shibataea chinensis> Pleioblastus argenteostriatus>Peiobastus fortunei>Sasa pygmaea according the absolute value and the relative value.While according the latter, the results was that Shibataea chinensis> Peiobastus fortunei >Pleioblastus.kongosonensis f. aureo-stratus>Pleioblastus argenteostriatus>Sasa pygmaea according the absolute value,while according the relative value the results was that Pleioblastus kongosonensis f. aureo-stratus > Pleioblastus argenteostriatus > Shibataea chinensis >Peiobastus fortunei>Sasa pygmaea .The author consider that the subordinate function method was more accurate.