Effects of NaCl Stress on the Growth,Ion Absorption and Distribution of Juniperus chinensis Seedlings
TANG Xiaoqian;LIU Guangquan;China Institute of Water Resources and Hydropower Research;Research Center of Saline and Alkali Land of State Forestry Administration;International Research and Training Center on Erosion &Sedimentation;
To understand the growth adaptability and salt tolerance mechanism of Juniperuschinensisseedlings under NaCl stress,we investigated the cationic absorption and distribution in different organs(such as roots,stems and needles)of the rawJ.chinensis seedlings and its biomass accumulation under different levels of NaCl(0,100,200,and 300mmol·L-1)stress through potted soil culturing in greenhouse.The results showed that:(1)with the increase of NaCl concentration,the growth including plant height,ground diameter,relative height growth and biomass accumulation were declined,while the root/shoot ra-tio was increased,indicating that the growth was inhibited;(2)under the NaCl stress,the Na~+concentrations in the roots,stems and needles of the J.chinensis seedlings were significantly increased compared with those of the contrast seedlings,and the Na~+concentration in the needles was significantly higher than that in stems and roots,the Na~+concentration in the needles was 5-fold higher in the roots;(3)with the increase of NaCl concentration,the K~+,Ca~(2+)and Mg~(2+)contents,K~+/Na~+,Ca~(2+)/Na~+and Mg~(2+)/Na~+ratios in different organs of the seedlings were decreased;(4)under the NaCl stress,the K~+-Na~+selective transportation coefficients(SK,Na),Ca~(2+)-Na~+selective transportation coefficients(SCa,Na)and Mg~(2+)-Na~+selective transportation coefficients(SMg,Na)of the roots were significantly decreased,but the SCa,Naand SMg,Naof the stems and needles were generally decreased,while SK,Naof the needles were significantly declined with the increase of NaCl concentration.And large amount of Na~+was retained in shoots,which was advantageous for reducing the damage of salt stress to roots.In conclusion,our findings suggested that the salt-adaptation mechanisma of J.chinensis seedlings were primarily implemented by root growth stimulation,stems and needles Na~+accumulation,and are also correlated with a remarkably increased ability of K~+,Ca~(2+)and Mg~(2+)selective transportation in roots and steadyability of K~+,Ca~(2+)and Mg~(2+)selective transportation in stems and needles.
【Fund】： “十三五”国家重点研发计划课题(No.2016YFC0501705、2016YFC0501602);; IWHR成果转化专项(No.沙1003012016)
【CateGory Index】： Q945.78
【CateGory Index】： Q945.78