Dynamic Changes of Tobacco-growing Soil Nutrients and Enzymes After Application of Amelioration Materials

[Objectives]This study was conducted to clarify the improvement effects of different soil amelioration materials such as lime,green manure and bio-organic fertilizer on acidic tobacco-planting soil.[Methods]The dynamic changes of soil pH,soil nutrients and enzyme activity were studied by applying lime,lime+green fertilizer,and lime+green fertilizer+biological organic fertilizer.[Results]①After the application of amelioration materials,the soil pH and available phosphorus content of tobacco-growing soil showed a stepwise change of first increasing and then decreasing,and became stable at 60 d after tobacco transplanting;the soil organic matter,alkali-hydrolyzable nitrogen and available potassium content showed a gradual change trend of"high-low-high";and the soil invertase and urease activity showed a gradual change trend of"low-high-low".②To 90 d after tobacco transplanting,the application of amelioration materials increased soil pH by 1.29-1.62 units,and increased organic matter content by 15.21%-20.86%,alkali-hydrolyzable nitrogen content by 6.83%-18.17%,available phosphorus content by 54.15%-217.85%,rapidly available potassium content by 11.42%-30.86%,soil invertase activity by 70.09%-18.93%,and soil urease activity by 64.07%-130.47%.③The combination of lime+green manure+alkaline microbial organic fertilizer had the best effect on the improvement of acidic tobacco-growing soil,and the effect of lime+green manure+acid microbial organic fertilizer on acidic soil was the second.[Conclusions]When applying lime,green fertilizer and alkaline bio-organic fertilizer should be applied to achieve sustainable improvement of strongly acidic soil.

LeCDJ1,a chloroplast DnaJ protein,facilitates heat tolerance in transgenic tomatoes

The roles of a tomato （Lycopersicon esculentum） chloroplast-targeted DnaJ protein （LeCDJ1） were investigat-ed using wild-type （WT） and sense transgenic tomatoes. The LeCDJ1 expression was upregulated by 38℃, 42 ℃, 45 ℃, NaCl, PEG, methyl viologen （MV） and hydrogen peroxide （H2O2）, but not by 30 ℃ and 35 ℃. Meanwhile, LeCDJ1 was involved in the response of plants to abscisic acid （ABA）. Under heat stress, the sense plants showed better growth, higher chlorophyll content, lower malondialdehyde （MDA） accumulation and relative electrical conductivity （REC）, and also less PSII photoinhibition than WT. Interestingly, the sense plants treated with streptomycin （SM）, an inhibitor of organellar translation, still showed higher maximum photo-chemistry efficiency of PSII （Fv/Fm） and D1 protein levels than the SM-untreated WT, suggesting that the protective effect of LeCDJ1 on PSII was, at least partially, independent of D1＆amp;nbsp;protein synthesis. Furthermore, the relatively lower super-oxide radical （O2^＊-） and H2O2 levels in the sense plants were considered to be due to the higher ascorbate peroxidase （APX） and superoxide dismutase （SOD） activity, which seemed unlikely dependent on their transcription level. These results indicated that LeCDJ1 overexpression facilitated heat tolerance in transgenic tomatoes.