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We aimed to explore changes in basic soil productivity (BSP) under different fertilization regimes in the Poyang Lake region, Jiangxi Province, China. Soil samples were collected from a long-term fertilization experiment (since 1981) that included treatments of no fertilization (CK), chemical fertilization (NPK), and combined chemical and organic fertilization (NPKM). Then, a three-year pot experiment (from 2012 to 2014) with double rice cropping was conducted with two different fertilization regimes (no fertilization, F 0 ; fertilization, F 1 ) using CK, NPK and NPKM soils. Grain yield and BSP were analyzed among soils with different fertilization regimes to identify the key factors driving changes in BSP. Results showed that grain yields in NPKM soil were higher than in NPK and CK soils regardless of fertilization in the pot experiment. Under the F 0 condition, annual grain yields of NPKM soil were 37.7%-143.9% and 20.8%-66.7% higher than CK and NPK soils, respectively. The BSP values of CK, NPK and NPKM soils in three years were 41.8%-53.1%, 45.2%-62.6% and 59.1%-88.1%, respectively. NPKM soil had significantly higher BSP than NPK and CK soils. Furthermore, there were significant positive correlations between soil organic matter and BSP as well as between organic carbon balance and BSP. These results suggested that long-term application of chemical and organic fertilizers could improve BSP in the double rice cropping system of the Poyang Lake region. In addition, soil organic matter and organic carbon balance are important factors for improving BSP in this region.

Cucumber (cv. Zhongnong 26) was used as material, the effects of NO 3 - -N/NH 4 + -N ratios on growth and physiological characteristics of cucumber seedlings under suboptimal temperature and light intensity (18 ℃/10 ℃,180 ± 20 μmol·m -2 ·s -1 ) were studied. Total nitrogen in the nutrient solution was equal and three NO 3 - -N/NH 4 + -N ratios, 26:2, 21:7 and 14:14, were applied as treatments. The results showed that cucumber treated by NO 3 - -N/NH 4 + -N=21:7 had the longest total root length, the biggest root volume and root surface area, and the maximum number of root tips. H + -ATPase activity and relative expression of genes encoding nitrate transporter (NRT) and ammonium transporter (AMT) in cucumber roots were increased significantly by the treatment of NO 3 - -N/NH 4 + -N=21:7. In addition, nitrate reductase (NR), glutamine synthetase (GS) and glutamate synthase (GOGAT) in cucumber leaves under the treatment of NO 3 - -N/NH 4 + -N=21:7 were higher. As a result, the nitrogen content and biomass of cucumber were significantly increased. Compared with the plants under the treatment of NO 3 - -N/NH 4 + -N=26:2 or 14:14, cucumber seedlings under the treatment of NO 3 - -N/NH 4 + -N=21:7 had the highest biomass and total dry mass (DM) which were increased by 14.0% and 19.3% respectively under suboptimal temperature and light intensity. In conclusion, under suboptimal environmental conditions, NO 3 - -N/NH 4 + -N ratio could be adjusted to increase nitrogen absorption and metabolism of cucumber and alleviate the de-trimental effects caused by suboptimal conditions and promoted the cucumber growth.

In order to explore reasonable utilization of vegetable residue, the effects of application of different levels (0, 15, 20, 30 t·hm -2 ) of tomato and cucumber residue compost on soil pro-perties, the leaf photosynthesis and the yield of vegetables were studied in solar greenhouse. The results showed that both kinds of vegetable compost could reduce soil bulk density, increase soil organic matter content, soil microbial biomass and soil enzyme activity, promote plant growth, and improve vegetable yield and quality. The more amount compost returned, the better was the effect on plant growth and yield. The positive effect of the vegetable residue compost application in the second cucumber growing season was more noticeable than that in the first tomato growing season, which indicated the application of vegetable residue compost could effectively promote soil fertility, increase vegetable yield and improve vegetable nutrient quality.

Taking tomato 'Zhongza 105' as test material, the influences of sodium naphthalene acetate (SNA) on growth and physiological characteristics of tomato seedlings under suboptimal temperature and light condition were investigated. The results showed that the dry mass, vigorous seedling index, root activity, total nitrogen content, net photosynthesis rate (Pn) of tomato seedlings were significantly decreased by suboptimum temperature and light treatment. In addition, the catalase activity and zeatin riboside (ZR) concentration were also reduced. However, the superoxide dismutase, peroxidase activity and the content of abscisic acid (ABA) were increased. Compared with treatment of the same volume distilled water on tomato seedlings under suboptimum temperature and light condition, the dry mass of whole plant and vigorous seedling index of tomato seedlings were significantly increased by 16.4% and 22.9%, as the total N contents in roots and leaves and Pn were also increased by 8.5%, 28.5%and 37.0%, respectively, with the treatment of root application of 10 mg . L-1 SNA. Besides protective enzyme activity and the root activity were improved, the indole acetic acid (IAA) and ZR concentration of tomato were raised, and ABA concentration was reduced. The results indicated that root application of certain concentration of SNA could promote the growth of tomato seedlings by increasing the tomato root activity, protective enzymes activity, Pn and regulating endogenous hormone concentration under suboptimum temperature and light condition.

This paper studied the changes of organic soil substrate properties with increasing cultivation years and their effects on the cucumber growth in solar greenhouse. The results showed that with increasing cultivation years, the physical and chemical properties of organic soil substrate deteriorated, which was manifested in the increase of bulk density and the decrease of total porosity, pH, and available nutrient contents. The numbers of bacteria and actinomycetes in the substrate decreased with increasing cultivation years, while that of fungi was in reverse. The cucumber growth was also affected to a certain extent, manifesting in the decrease of plant height and leaf area, the decline of photosynthetic efficiency, and the decrease of yield and quality. It would be necessary to restore the fertility of organic soil substrate after 3-year cultivation.

By adopting organic substrate culture, and salt-sensitive cucumber variety 'Jinchun No. 2' was used as test material, this paper studied the effects of inoculating arbuscular mycorrhiza fungi (AMF) on the plant growth, fruit yield, and fruit quality of cucumber under salt stress. AMF-inoculation could effectively promote the plant growth and nutrient uptake, and improve the fruit yield and fruit nutrient quality, compared with ordinary cultivation. Under salt stress, the plant growth was inhibited, and the plant N, P, K, Cu, and Zn contents and K+/Na+ ratio, fruit yield, and fruit soluble protein, total sugar, vitamin C, and nitrate contents decreased, while inoculation with AMF could mitigate the inhibitory effect of salt stress on the plant growth, made the plant N, P, K, Cu, and Zn contents increased by 7.3%, 11.7%, 28.2%, 13.5%, and 9.9%, respectively, and made the plant K+/Na+ ratio, fruit yield, and fruit soluble protein, total sugar, and vitamin C contents have an obvious increase and the fruit nitrate content have a significant decrease. It was suggested that AMF could promote the plant growth and nutrient uptake of cucumber under salt stress, increase the plant salt-tolerance, and improve the fruit yield and its nutrient quality.

Taking the energy-saving solar greenhouses with the same infrastructure but different sunken depths (0, 0.5, 1.0, and 1.5 m) in Tai' an of Shandong Province as test objects, this paper analyzed the intercepted amount of direct solar radiation energy, and studied the diurnal variation and spatial distribution patterns of environmental factors in the greenhouses on winter solstice (December 20-24, 2009) and summer solstice (June 19-23, 2010). With the increase of sunken depth, the shadow areas in the greenhouses caused by sunken profiles increased gradually, the direct solar radiation energy into the interior of the greenhouses shifted from south to north, and the ratio of ground radiation to back wall radiation decreased gradually. Within the range of 0-1.0 m sunken depth, the air temperature and soil temperature in the greenhouses increased significantly with increasing sunken depth; but when the sunken depth was 1.5 m, the warming effect declined significantly, and the deviation of the lowest soil temperature increased. The deeper the sunken depth, the lower the light intensity and the higher the relative humidity in the greenhouses were. In considering of both lighting and heat preservation, the appropriate sunken depth of energy-saving sunlight greenhouses with a span of 10 m in Tai' an region should be less than 1.0 m.

In order to investigate the responses of ascorbic acid (AsA) metabolism system in potato leaves to high and low temperature stresses, a pot experiment was conducted with potato plants exposed to 40 degrees C or 5 degrees C, with the leaf AsA content, mRNA expression level of GalLDH and DHAR genes, activities of GalLDH, DHAR, APX, MDHAR and GR, and contents of hydrogen peroxide (H2O2) and malondialdehyde (MDA) determined. Under the exposure to 40 degrees C, the leaf AsA content increased rapidly and reached the highest (43.7% higher than the control) at 6 h, followed by a rapid decrease. Under the exposure to 5 degrees C, the AsA content also increased first, reached the highest (27.7% higher than the control) at 9 h, and then decreased. Under the two temperature regimes, the activities of leaf GalLDH, DHAR, APX, MDHAR and GR decreased after an initial increase, the mRNA expression level of GalLDH and DHAR genes showed the similar changes with their corresponding enzyme activities, and the leaf MDA and H2O2 contents increased remarkably after 24 h. All the results suggested that the AsA metabolism system in potato leaves was stimulated in the early period of high- and low temperature stresses, but its function declined gradually with the duration of the stresses.

This paper studied the relative expression of Mn-SOD, Cu/Zn-SOD and CAT mRNAs and the changes of SOD, Mn-SOD, Cu/Zn-SOD and CAT activities in grafted and own-rooted cucumber leaves under low temperature stress, and their relations with the cold resistance of cucumber. For both grafted and own-rooted cucumber leaves, the relative expression of Mn-SOD and Cu/Zn-SOD mRNAs under low temperature stress was respectively accordance with the changes of Mn-SOD and Cu/Zn-SOD activities, while the expression of CAT mRNA was not accordance with the change of CAT activity. The relative expression of Mn-SOD and Cu/Zn-SOD mRNAs and the activities of SOD, Mn-SOD and Cu/Zn-SOD in grafted cucumber leaves were higher than those in own-rooted cucumber leaves, while the MDA content and electrolytic leakage were in adverse. The higher SOD activity regulated by the higher SOD mRNAs expression in grafted cucumber leaves might be the key factor of grafted cucumber having a higher cold resistance to low temperature stress than own-rooted cucumber. The relative expression of CAT mRNA was slightly higher in functional leaves but lower in young leaves of grafted cucumber, while less difference was observed in CAT activity, comparing with own-rooted cucumber, which illustrated that low temperature stress had lesser effects on the relative expression of CAT mRNA and the activity of CAT in grafted cucumber leaves.

Taking grafted and own-root cucumber (Junlv No. 3) plants as test materials, the changes of their leaf Cu/Zn-SOD, Mn-SOD and CAT mRNA relative expression, leaf SOD, Cu/Zn-SOD, Mn-SOD and CAT activities, leaf MDA content, and leaf electrolytic leakage under NaCI stress were studied. The results showed that under NaCl stress, grafted cucumber had a higher relative expression of its leaf Cu/Zn-SOD, Mn-SOD and CAT mRNA, and higher activities of its leaf SOD, Cu/Zn-SOD, Mn-SOD and CAT, compared with own-root cucumber, which suggested that the higher relative expression of Cu/Zn-SOD, Mn-SOD and CAT mRNA in grafted cucumber leaves resulted in the higher activities of their SOD, Cu/Zn-SOD, Mn-SOD and CAT. With the NaCl stress prolonged, the relative expression of Cu/Zn-SOD, Mn-SOD and CAT mRNA in both grafted and own-root cucumber leaves had an increasing trend, but the changing trend of Cu/Zn-SOD, MnSOD and CAT activities were not the same as that of mRNA, indicating that the activities of SOD and CAT were also regulated by other factors. The leaf MDA content and electrolytic leakage of grafted cucumber were lower than those of own-root cucumber, suggesting that grafted cucumber had a higher scavenging metabolism, which could decrease oxidative damage and increase its salt-tolerance.

With tomato cultivar Qifen as test crop, this paper studied its growth, physiological characters, fruit yield, fruit quality, and water use efficiency (WUE) under effects of relative moisture content of organic substrate. The results showed that with increasing moisture content in organic substrate, the plant height, stem diameter, node length, leaf area per plant, leaf pigment content, water potential, osmotic potential, root vigor, and fruit yield increased markedly, but fruit quality and WUE decreased significantly. Considering from the aspects of fruit yield, fruit quality and WUE, 80% moisture content of organic substrate could be used as a favorable quantitative index for the water management of tomato cultivation, under which, 26 kg x m(-2) fruit yield could be achieved. If only considering fruit quality, 50% moisture content could be used as the index for water management.

With two cucumber varieties (greenhouse variety Jinyou No. 1 and open-field variety Jinyan No. 4) as test materials, this paper measured their net photosynthesis rate (P(n)) under given environmental conditions including CO2 concentration, temperature and illumination intensity in phytotron, and the responses of P(n) (y) to these factors were modeled by mathematic methods, which could be described as y = exp (- 242. 1217/x1) [61.0202 - 0.11 (x2 - 30.926)2] exp (-272. 8874/x3) + 0.9355 for Jinyou No. 1, and y = exp (- 179.8803/x1) [50.0771-0.0609 (x2 -34.3455)2] exp (-267.9653/x3) + 0.7377 for Jinyan No. 4, where x1, x2 and x3 represented the values of CO2 concentration, temperature, and illumination intensity, respectively. The response of P(n) to temperature accorded with conic function, while its responses to CO2 concentration and illumination intensity accorded with exponential function.