Effects of Lanthanum on Redox Systems in Plasma Membranes of Casuarina equisetifolia Seedlings Under Acid Rain Stress

The effects of lanthanum on some redox system(PMRS) properties of the plasma membrane(PM) vesicles from Casuarina equisetifolia seedlings under artificial acid rain(pH 4.5)stress were studied. The results show that there are NADH oxidase and EDTA Fe 3+ reductase, and nitrate reductase in the seedling PM, and they have different responses to soaking seeds for 8 h in a series of LaCl 3 solution. The NADH oxidase activities and the Nitrate reductase activities can be stimulated when La 3+ concentrations is in the range of 50～200 mg·L -1 , but their activities are inhibited or fluctuate by the higher La 3+ concentrations. The EDTA Fe 3+ reductase activities can be stimulated by La 3+ concentrations in the range of 50～400 mg·L -1 . The research also revealed that La 3+ reduces the relative permeability of membranes and have the function in protecting membranes under acid rain stress by the way of inhibiting the leakage of electrolyte.

Effects of La^(3+) on ATPase Activities of Plasma Membrane Vesicles Isolated from Casuarina Equisetifolia Seedlings under Acid Rain Stress

The effects of La^(3+) on the growth and the ATPases activities of plasma membrane(PM) vesicles isolated from Casuarina equisetifolia seedlings under artificial acid rain(pH 4.5) stress were studied. The results show that the height, length of roots, fresh weight and PM H^+-ATPase activites of Casuarina equisetifolia seedlings increase by the treatments of soaking seeds in LaCl_3 solutions with lower concentrations, and those can reach their peak values by treating with 200 mg·L^(-1) La^(3+). However, in comparison with the CK, those are inhibited by the higher La^(3+) concentrations; PM Ca^(2+)-ATPase activity is inhibited with the treatments of La^(3+). The results also reveal that the H^+-ATPase activity and the growth of cell enlarge have a remarkable positive correlation, and La^(3+) activating H^+-ATPase can facilitate plant growth. La^(3+) also can alleviate cytosolic acidification of plant under acid rain stress and indirectly maintain the stability of intracellular environment. In order to resistant to acid rain and accelerate the growth of Casuarina equisetifolia, the suitable range of La^(3+) concentrations to soak seeds for 8 h is 50～200 mg·L^(-1).

Accumulation of Rare Earth Elements in Spinach and Soil under Condition of Using REE and Acid Rain Stress

The content and distribution characteristics of REE in spinach and soil under using REE and acid rain stress were studied by pot experiments. The results show that the content of REE is 0 527～0 696 (μg·g -1 ) in the above ground portion of spinach, 2 668～3 003 (μg·g -1 ) in the under ground portion of spinach and 229 09～250 30 (μg·g -1 ) in the soil. With the acidity of acid rain increasing, the leaching of REE in plants and soil is strengthened and the amount of REE reduces with decreasing of pH value. After REE are used, though plants show the selective absorption to Ce group elements (especially spraying on leaves), regardless under acid rain stress or using REE or not, the distribution model of REE in the above ground and under ground portion of plants is basically the same with the control. Plants also follow the Oddo Harkins rule of the REE of distribution abundance, light rare earth elements is enriched, the minus of Eu is abnormal and admeasure of Ce is a rich model. The results show that REE in plants mainly come from soil and are affected by it.

UV-Vis Spectroscopy Study on Interaction between Microperoxidase-11 and Pr Ion Under Acid Rain Stress

Interaction between rare earth ion praseodymium (Pr(Ⅲ)) and MP11 with/without hydrogen ion (H +) in different media( aqueous, phosphate buffer, physiological condition) were studied by UV Vis spectroscopy. All the results indicate that Pr(Ⅲ) interacts with MP11, increasing the non planarity of porphyrin periphery, leading MP11 to form two conformations when titrated by Pr(Ⅲ). Excessive Pr(Ⅲ) acts as a contaminant in living organism. H + and Pr(Ⅲ) have antagonistic effect on MP11, suggesting that at suitable concentration under physiological conditions, Pr(Ⅲ) can be used as biomodulator in protecting plants from acid rain stress or in rehabilitating the harm.

Response of peroxidase and catalase to acid rain stress during seed germination of rice,wheat,and rape

Seed germination of plants with various acid-resis tance display different responses to acid rain.To understand the reason why such differences occur,the effects of sim ulated acid rain(pH 2.5-5.0)on the activities of peroxidase(POD)and catalase(CAT)during sced ger-mination of rice(O.sativa),wheat(T.aestivurm),and rape(B.chinensis var.oleifera)were investigated.R cesults indi-cated that the maximum change in activities of CAT and POD by acid rain treatment with different acidity and time in relation to the referent treatment without acid rain,was in the order:rice(28.8%,31.7%)<wheat(34.7%,48.3%)<rape(79.3%,50.0%).The pH level for which the treatment with acid rain did not cause signif-cant difference(p<0.05)was in the order:rice(3.5)>wheat(4.0)>rape(5.0).Moreover,the change in activity of POD was higher than that of CAT,which showed that POD was more sensitive to acid rain stress than CAT.The difference in the ability of POD and CAT in removing free radicals was one reason why the germina-tion indexes of these three species behaved differently.