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Responses Of Desert Halophyte Foliar Stoichiometry And Photosynthetic Characteristics To N And P Additions

Posted on:2016-06-15Degree:MasterType:Thesis
Country:ChinaCandidate:Y MaFull Text:PDF
GTID:2180330476450300Subject:Ecology
Abstract/Summary:PDF Full Text Request
Arid region located in the inland arid climate is harsh, with fragile ecological environment, so it plays an important role in maintaining the stability of the ecological system of desert vegetation. The ecological stoichiometry mainly study the element balance between the environment and biological carbon(C), nitrogen(N), phosphorus(P) and their impact on ecological process,which is a new theory.The addition of N, P nutrient, will affect the retention characteristics of plant nutrient, especially in arid areas, the lack of N tends to suppress the plant growth.So study the effects of the addition of N、P nutrients to desert halophyte foliar stoichiometry and photosynthetic characteristics can provide scientific basis for deeply understanding the connotation of arid area in ecological processes, the restoration and reconstruction of vegetation resources in the arid areas, resource recycling and ecological environmental management.This text uses the method of field test and indoor experiment, studies the change of the foliar nutrient content of Alhagi sparsifolia、Nitraria sibirica Pall. in different N、P addition levels, the corresponding soil ecological stoichiometry characteristics and the foliar photosynthetic characteristics and so on, The main results indicated:(1)According to soil EC before fertilization, Alhagi sparsifolia habitat and Nitraria habitat were divided into high salt(LTC1)、middle salt(LTC2) 、low salt(LTC3) and high salt(BC1)、low salt(BC2),respectively.The average of soil EC、p H in Nitraria sibirica Pall. habitat were higher than that of Alhagi sparsifolia before fetilization,fertilization increased soil p H in LTC1,significantly.(2)Compared with the Yellow River estuary wetland and the national average of soil nutrients, the study area had low soil C, N, P contents. Fertilization had no significant effect on soil C content. Soil C contents in some samples were lower than CK(LTC2, LTC3, BC1),others were higher than that of CK(LTC1, BC2). The soil N contents in different habitats were lower than that of CK(except BC2) after fertilization, there were not significant difference between CK and soil P 、AP contents in different treatments level and in different habitats.(3)Fertilization had significant effects on the contents of leaf C, N, P and N/P, the leaves N content of LTC2 was significant higher than that of CK in LN and P treatment, the leaves N content of BC2 was significant decreased in PHN treatment. The leaves P content of LTC3 was significantly higher than that of CK in HN treatment, the leaves P content of BC1 was significant lower than that of CK in PLN treatment. There was no uniform regular with the foliar N/P in study area, so the plant foliar nutrient limitation elements were hard to judge.(4)The different foliar nutrient indexes had reached significant level in different habitats(except LTC3). From the relationship between plant foliar nutrient elements soil factors,we got that: plant nutrients were mainly affected by soil salinity and p H in high salt habitat, there was a positive correlation between plant nutrient and soil salinity and p H in Alhagi sparsifolia habitat;the plant nutrients were mainly effected by soil salinity and soil C contents in middle habitat;the plant nutrients were mainly affected by soil nutrient contents in low salt habitat(LTC3), BC1 was effected by soil nutrients and p H, there was a negative correlation between plant nutrient contents and soil nutrients.(5)There was no significant differences between plant photosynthetic characteristics and CK in the two habitats after fertilization. The former plant photosynthetic index contents were higher in LN treatment than that of HN treatment, the other vice to the latter. The plant Pn and PNUE of LTC1 was significantly higher than that of CK in LN treatment, The plant Pn and PNUE of LTC3、BC2 were significantly lower than and higher than that of CK in HN treatment,reapectively. The plant Pn of BC1 was significant lower than that of CK in LN treatment.(6) In LN treatment, there was a negative correlation between the plant Chl and leaf N contents of LTC1,it also had reduced the correlation coefficient of plant Pn and the leaf nutrient content, the effect of HN treatment on the correlation of LTC1、LTC2 was not significant,the plant Pn and P nutrients of LTC3 were significantly positive correlation in HN treatment.The plant PNUE and N contents of BC1 only in HN treatment were negatively correlated,LN treatment had no significant effect on the correlation coefficient of LTC3、BC1.The plant Chl and C content of BC2 had a significantly negative correlation in LN treatment, the HN had decreased the correlation coefficient of BC2.
Keywords/Search Tags:Stoichiometry, photosynthetic characteristics, nitrogen and phosphorus addition, Alhagi sparsifolia, Nitraria sibirica Pall
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