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Scientia Silvae Sinicae ›› 2015, Vol. 51 ›› Issue (9): 35-41.doi: 10.11707/j.1001-7488.20150905

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Ion Fluxes of Multiple Transgenic Populus×euramericana‘Guariento’ under Salt Stress

Li Dan, Huang Juan, Zhang Weixi, Ding Changjun, Su Xiaohua, Huang Qinjun   

  1. State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry Chinese Academy of Forestry Beijing 100091
  • Received:2015-02-02 Revised:2015-03-20 Online:2015-09-25 Published:2015-10-16

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Abstract:

[Objective] Intracellular K +/Na + homeostasis is crucial for cell metabolism and is considered to be a key component of salinity tolerance in plants. [Method] The plant height,dry biomass of roots and net fluxes of Na+,K+,H+ from apex roots(using non-invasive micro-test technology) were investigated in the multiple transgenic Populus×euramericana ‘Guariento’(named D5-21,D5-20)and non-transgenic species(named D5-0)under 100 mmol·L-1 NaCl stress at three different period. [Result] Growth data indicated that: compared with control, all of the three lines had a lower height after 7 days of salt stress treatment, but no significant declined; But after 15 days treatment, the plant height of D5-20, D5-0 was declined significantly;when the treatment extended to 30 days, the height of three poplar lines and their amount of dry matter in root were significantly reduced, the D5-0 and D5-21 remained only 50% of dry matter compare with normal water supply conditions, these data showed that salt stress inhibited the growth of poplar roots seriously; meanwhile, the phenotypic changes showed that, compare to D5-0, D5-21,D5-20 were under lower danger level, had higher height and more dry matter in root after treatment. Na+ fluxes results showed that: there is a significant change of each line roots' Na+ fluxes after 7 days of stress treatment, but the magnitude is too small; D5-21,D5-20 roots' Na+ extruding capacity is 1.8 times of D5-0 after 15 days of stress treatment; D5-21,D5-20 roots' Na+ extruding capacity is 1.6 times of D5-0 after 30 days of stress treatment.K+ fluxes results showed that as stress time continues, D5-0, D5-21 roots' K+ effluxing increased,D5-20 is then decreased,but the trends are quite different, D5-0 roots' K+ effluxing capacity is 1.7 times of D5-21 and 2.1times of D5-20 after 30 days of stress treatment. H+ fluxes results showed: as stress time continues,all the three lines roots' H+ influxing increased, but the increasing of D5-21、D5-20 is significantly greater than D5-0; D5-21,D5-20 roots' H+ influxing capacity is 1.6 times and 1.2 times of D5-0 after 30 days of stress treatment.So, whether it is short-term (7 days), medium-term (15 days) or long term (30 days) salt stress treatment,transgenic lines D5-21, D5-20 exhibited a higher capacity to extrude Na+ ,meanwhile,the influx of H+ had a significant increasing, and a less reduction of K+ versus D5-0, Thus, the transgenic poplar species can avoid excessive cytoplasmic Na+ accumulation by extruding Na+ ,and decreased the K+ leakage from cytoplasmic,and these two measuremtnts are helpful to maintain K+/Na+ homeostasis. Therefore, transgenic poplar species implied an increased salt tolerance and growth accumulation,this will provide a new evidence for salt tolerance screening of transgenic trees. [Conclusion] JERF36 gene is a ERF transcription factor that can activates the expression of downstream stress resistance genes, and is closely related with plants resistance.So the relationship between JERF36 gene and the gene expression involving in the transport of Na +, H +, K + ions deserves to take a further study.

Key words: Populus×, euramericana 'Guariento', JERF36, ion fluxes, salt tolerance

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