Characteristics Of Seed Germination Of Karst Forest Plants

For knowing the adaptation of karst plants to karst Environment,seeds of three karst plants(Eurycorymbus cavaleriei(Levl.)Rehd.et Hand.-Mazz.,Cinnamomum bodinieri Levl, Cydobalanopsis glauca(Thunb.)Oerst)and acid soil plant(Rhododendron ovatum Planch) are studied by experiments,using different(0,5,10,20,40mmol/L)concentration of Calcium (CaCl₂ & Ca(NO₃)₂)soaking 24h on germination of seeds.Meanwhile,the papers analyze the variation of germination indexes of seeds,and analyze the variation of germination,physio-logical and biochemical indexes of the four species,which are osmotic stressed by 10% PEG-6000 after being dealed with different(0,5,10,20mmol/L)concentration of CaCl₂ to study the effect of Ca²⁺on their drought-resistant ability.The main results as follows;1.The different exteral calcium(CaCl₂ & Ca(NO₃)₂)and the different Ca²⁺concen-tration soaking seeds,the germinate processes influence of 4 species mainly to manifest in the difference which the germinates time,the germination rate,germinates speed,seedling radicle and plumule growth influence.The different seeds the most suitable germination Ca²⁺concentration processing which germinates and seedling growth differently,the E.cavaleriei,C.bodinieri and C.glauca's most suitable Ca²⁺concentration is 20 mmol/L, the R.ovatum.'s most suitable Ca²⁺concentration is 10 mmol/L,Through to above various parameters synthesis comparison discovery,CaCl₂ is advantageous to the E.cavaleriei, C.bodinieri and R.ovatum's germination.Ca(NO₃)₂ is advantageous to the C.glauca's germination.2.The exteral Ca²⁺to the physiological and biochemical process of germination have the certain influence under drought stress,displays for can alleviate the relative water content to reduce,enhances the SOD and POD activities,suppresses the MDA content rise, the promotion soluble sugar content accumulation and the suppression soluble protein decomposition.Along with drought stress the time lengthening,5 mmol/L Ca²⁺concen-tration processes to the R.ovatum.'s's promoter action in a bigway,10mmol/L Ca²⁺concen-tration processes to the E.cavaleriei,C.bodinieri and C.glauca's promoter action is bigger.3.Uses Fuzzy Function on the integrative drought-resistance values of the four species with the germination indexes,physiological and biochemical indexes,the two analysis result is consistent.The sequence of the comprehensive drought-resistance capability(DA) is;E.cavaleriei＞C.glauca＞C.bodinieri＞R.ovatum.In conclusion,the exteral Ca²⁺to drought-resistance to the karst plant to have the different influence under drought stress.In comparison,the calcicolous tree and the middle tree can resist to slight drought stress under exteral Ca²⁺,and can use Ca²⁺to regulate drought- resistance.This is in the karst forest plants long-term adaption the calcareous soil and the temporary arid of karst environment result.