| Using simulated fumigation, the influence of sulfur dioxide(SO2) stress on one-year-old potted saplings of four tree species [Eucalyptus grandis(referred to as "A"), Dendrocalamus affinnis(B), Cunninghamia lanceolata(C), Alnus cremastogyne(D)], whi-ch were the the major species for afforestation in Sichuan Province were studied. The levels of SO2in the experiment were Natural state (CK),1.5ppm (S1) and3ppm (S2). After30d of processing, leaf modality, its physiological and biochemical indices were determined. And then their characteristics and relative mechanism of response to SO2stress were analyzed. The results showed that:(1) The injury symptom and its level of four tree species influenced by SO2stress were different, and they got worse with the increase SO2. The injury symptom and level of A and D was worst, C was worse, and B was the slightest; for the occur-rence time of injury(the symptom could be macroscopic), the first was D in the treat-ment S1, and A and D in S2.(2) Along with the increase of SO2, the content of total chlorophyll(Chl) and Chl a/b rate of A, C and D decreased, the decrease of total Chl of D was the most obvious, meanwhile, the decrease of Chl a/b rate of A was the most obvious. the total Chl of B showed the trend of increase, and compared with CK, it increased by44.52%and30.79%in S1and S2respectively. the Chl a/b rate decreased initially and then increased, S2was1.78times of CK.(3) Along with the increase of SO2, Net photosynthesis rate(Pn) of A and D in-creased. Pn of B decreased most obviously, and there was no significant change for B.(4) The content of malonaldehyde(MDA) of A, B, D increased along with the increase of SO2, and the most obvious was A; the C decreased first and then increased, MDA in S1decreased by49.92%, then that in S2increased by90.70%. (5) Following the increase of SO2, the content of proline(Pro) of A and D increased, Pro of A and D in treatment S2was13.11and0.68times of CK respectively, meanwhile that of B and C decreased, there was no significant difference (p>0.05) between B and CK. while in S2, the Pro of B decreased by34.09%, in S1and S2, that of C decreased by46.50%and31.84%.(6) The content of soluble sugar(SS) of A, B, D increased, but C initially decreased and then increased, with the increase of SO2. In S1, the SS of A, B and D increased by21.02%,26.36%and41.12%respectively, yet C decreased by35.26%; In S2, SS of all increased by123.68%,50.82%,43.15%and151.34%respectively.(7) The variation of soluble protein(SP) of A, B, D was the same as SS but that of C had the trend of increase fist and then decrease. The SP content of B decreased by69.95%compared with CK; In S2, SP contents of all tree species were1.09,1.16,1.5and2.15times of CK respectively.(8) With SO2increasing, the POD activity of A increased,S2of it was26.49times of CK, there was no significant change for the SOD activity, and the CAT activity had not been determined; the POD, SOD and CAT activity of B increased; the POD activity of C had the trend of increase fist and then decrease, the SOD activity increased gradiently, meanwhile, the CAT activity decreased, S1of it was minimum with being decreased by30.63%; the POD activity of D increased, S1of it was maximum, the SOD activity increased gradiently, the CAT activity had the trend of increase fist and then decrease, S1of it decreased by40.63%, and then S2of it was1.26times of CK.(9) With the increase of SO2, the sulphur content of leaf of all species increased. The order of SO2absorption ability for the four tree species was:B>C>D>A.According to all indexes discussed above, In indicated that the response of decidu- ous species(A and D), coniferous species(C)and gramineous species(B) to SO2stress are completely different, and the basic reason maybe the different structure of blade. |
PDF Full Text Request