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Yang Z.-Q.,Nanjing University of Information Science and Technology | Yang Z.-Q.,Jiangsu Key Laboratory of Agricultural Meteorology | Tan W.,Nanjing University of Information Science and Technology | Liu Z.-X.,Nanjing University of Information Science and Technology | Chen Y.-Q.,Shenyang Central Meteorological Observatory
Chinese Journal of Ecology | Year: 2015

An experiment was conducted to examine the influence of soil water stress on the stomatal characters of greenhouse tomato leaves in May to August 2013. With Jingfen-2 as the test material, four soil moisture grades were included in this experiment: well watered (70%-80% of water holding capacity) , mild stress (60%-70% of water holding capacity) , moderate stress (50%-60% of water holding capacity) and severe stress (30%-40% of water holding capacity). Digital microscopic imaging system and digital measuring system were applied to measure the stomatal length, width, aperture, and density. The results showed that the stomatal length and width, stomatal aperture and open ratio of tomato leaves decreased with the increase of water stress, and the reduction amplitude increased with the extension of stress time. Tomato stomatal length and width decreased synchronously, but the stomatal length was more significantly decreased than the stomatal width with the increase of water stress. The stomata gradually changed from long ovate to suborbicular. The stomatal density of the upper epidermis increased gradually, while the stomatal density of the lower epidermis presented a trend of decreasing first and then increasing. This study provided the scientific basis for water management of greenhouse tomato. © 2015, editorial Board of Chinese Journal of Ecology. All rights reserved. Source

Yang Z.Q.,Nanjing University of Information Science and Technology | Yang Z.Q.,Jiangsu Key Laboratory of Agricultural Meteorology | Qiu Y.X.,Nanjing University of Information Science and Technology | Liu Z.X.,Nanjing University of Information Science and Technology | And 2 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2016

Soil moisture plays a key role in determining tomato growth, yield, and quality. Soil moisture directly or indirectly affects the growth and distribution of the root system. Under soil moisture stress, plant water and nutrient uptake depend on root size, morphology, and competition. It is important to study tomato root growth under different soil moisture treatments to optimize water and nutrient utilization efficiency. Previous studies have mostly investigated the physiological and biological effects of soil moisture on tomato fruit, and many studies have discussed certain aspects of individual mechanisms. In this study, the growth of both roots and all above-ground parts of tomato plants under each moisture treatment was observed. Soil moisture data were combined with whole plant growth status to reveal dynamic changes in tomato roots and above-grounds part in response to soil moisture stress.We used the tomato (Lycopersicon esculentum) cultivar ‘Jingfen 2’ in our experiment, which was performed in a controlled environment greenhouse at the Nanjing University of Information Science and Technology from May to August of 2013. Four soil moisture treatments were applied:normal water supply (T1), mild water stress (T2), moderate water stress (T3), and severe water stress (T4). The growth of roots and above-ground parts of tomato plants were observed. Among the four soil moisture treatments, measurements of four root growth parameters (total root length, total root surface area, average root diameter, and number of root tips) were in the following descending order:T2 > T3 > T1 > T4. Maximum total root length in T2, T3, and T4 was 1.8-, 1.0-, and 0.4-fold that of T1, respectively. Total root surface area in T2, T3, and T4 was 2.3-, 1.1-, and 0.4-fold that of T1, respectively. Average root diameter in T2, T3, and T4 was 1.3-, 1.1-, and 0.6-fold that of T1, respectively. Root tip number in T2, T3, and T4 was 1.1-, 1.0-, and 0.5-fold that of T1, respectively. In T1, T2, and T3, tomato roots were distributed mainly in the 5-10 cm soil layer, but in T4 most roots were in the 15-25 cm layer. Plant height, stem diameter, and leaf area index (LAI) of tomato plants decreased with increasing soil moisture stress. Compared with T1, plant height in T2, T3, and T4 was reduced by 11.49%, 28.60%, and 43.98%, respectively. The minimum stem diameter was found in T4, which was 73.57% of the tomato stem diameter in T1. LAI differed significantly (P <0.05) among soil moisture treatments; LAI in T2, T3, and T4 was 81.33%, 64.62%, and 43.37%, respectively, of that in T1. Soil moisture was positively correlated with growth indices of root and above-ground parts, and soil moisture content in the 20-cm layer had the highest correlation with root growth indices. The mild water stress treatment (T2) did not significantly affect the growth of above-ground parts, while it benefited root growth. The moderate and severe water stress treatments (T3 and T4) significantly inhibited the growth of above-ground parts and decreased the extent of root distribution in the soil. The results of this study may provide a scientific basis for water management in greenhouse tomato production. © 2016, Ecological Society of China. All rights reserved. Source

Zhang S.-J.,Institute of Atmospheric Environment in Shenyang | Yang Z.-Q.,Nanjing University of Information Science and Technology | Chen Y.-Q.,Liaoning Meteorological Bureau | Han X.-J.,Shenyang Central Meteorological Observatory | And 3 more authors.
Chinese Journal of Ecology | Year: 2014

In order to study the physiological mechanism of the effects of low temperature, weak light and high humidity stresses on tomato in winter in Northeast China, a tomato cultivar ‘Liang-fen 2’ was selected as experimental material, and four levels of low temperature (5-2-4 ˚C; 5- 1-3 ˚C; 5-0-2 ˚C; 5-(-1)-1 ˚C), weak light [0 (2 days)-400 µmol· mol-1] and high humidity (70%-95%) were installed in a climatic chamber to study their effects on maximum net photosynthesis rate, chlorophyll fluorescence parameters and antioxidant enzyme activities. Results showed that the original light conversion efficiency of the PSII and its potential activity were reduced under low temperature, weak light and high humidity stresses. In addition, the maximum net photosynthesis rate (Pmax), photochemical maximum efficiency of PS II (Fv/Fm), potential activities of PS II(Fv/F0) and photochemical quenching coefficient (qP) decreased with the decline of temperature and the extension of the duration of low temperature. At the same time, non-photochemical quenching coefficient (qN) increased along with the decline of temperature, while the activity of superoxide dismutase (SOD) and the content of malondialdehyde (MDA) increased simultaneously. After the temperature recover, Pmax, Fv/Fm, Fv/F0,qP and the content of MDA increased, while non-photochemical quenching coefficient (qN) and SOD activity decreased. All the physiological and biochemical indicators did not recover to the first day’ s level except Pmax of treatments 1 and 2. Meanwhile, the physiological and biochemical indicators did not return to CK levels. Our results suggested that temperature below 5 ˚C, weak light and high humidity stresses damaged the tomatoes. Therefore, we concluded when temperature declined to 5 ˚C or below 5 ˚C and the duration reached 3 days, as well as the minimum temperature reached 0 ˚C, the freezing injury would happen to tomato. © 2014, Editorial Board of Chinese Journal of Ecology. All rights reserved. Source

Zhou B.,Liaoning Institute of Meteorological science | Li J.,Liaoning Institute of Meteorological science | Lin J.-J.,Chongqing Three Gorges University | Lin J.-J.,CAS Shenyang Institute of Applied Ecology | And 3 more authors.
Chinese Journal of Ecology | Year: 2015

The soil relative moisture characteristics of Liaoning in seeding period and the relationships between soil relative moisture and soil property, crop varieties and meteorological factors were studied. Statistical methods were adopted including correlation analysis, regression analysis, factor analysis and interpolation analysis. Data collection covered the soil parameters and the daily value of conventional meteorological factors from 49 weather stations in Liaoning from March to May, 2004-2013, soil moisture data from agro-meteorological experimental stations in western Liaoning in May, 2004-2010 and regional soil parameters of Liaoning. The relative soil moisture of Liaoning in spring increased by 1.6% per year on average, and it was usually higher in the southeast than in the northwest. In most parts of the province, the soil water-holding capacity was 20%-25%. Crop tillage would reduce soil relative moisture by 5.6%-36.4%. Among the meteorological factors, soil relative moisture in previous period had the greatest impact on soil relative moisture (r = 0.48), and vapor pressure had the least (r = -0.08). Soil relative moisture was influenced by soil property, cultivated crop varieties and various meteorological factors, which we should take full account in soil moisture forecast during seeding time in spring. © 2015, editorial Board of Chinese Journal of Ecology. All rights reserved. Source

Jiang D.,Shenyang Central Meteorological Observatory | Cai K.,Shenyang Central Meteorological Observatory
2012 2nd International Conference on Remote Sensing, Environment and Transportation Engineering, RSETE 2012 - Proceedings | Year: 2012

Based on data from the China new-generation weather radar (CINRAD), a comprehensive study is performed of three heavy snow processes in the south of Northeast China during 2004-2007. Results show that the heavy snow in the south of Northeast China (HSSNC) is characterized as follows: 1) the area of echo over 18 dBZ is larger than 5*10 3km 2 in the CINRAD base reflectivity product and hourly snowfall is positively correlated with the snow echo; 2) there is large gradient of echo intensity at the boundary between rainfall and snowfall; 3) the echo intensity of the study snow is usually less than 30 dBZ, and the snow is mainly made up of liquid precipitation particles or melting solid precipitation particles when the intensity is larger than 40 dBZ; 4) the precipitation features and rain-snow boundary can be distinguished according to the echo intensity and its gradient, and the radiosonde and surface temperature records, which is meaningful to the forecast. At the beginning of heavy snowfall process, the zero line is clear with a structure like "S", which is the structure of warm advection wind. At the mature stage, the recombination wind field which is superposition of warm advection and large scale convergence predicts that the echo would be strongest. For the products of wind profile, the low-level water vapour transport has a direct intuitive significance for the change of precipitation intensity. During the heavy snow processes, the height of the echo top (ET) is low, slightly changing and relatively even, with its area a little smaller than that of the base intensity product. Meanwhile, products of the vertically integrated liquid (VIL) underestimate evidently the snowfall, and its area is much smaller than area of base reflectivity. Doppler radar detection and estimation of the hourly snowfall by optimization method on the extremely heavy snow on March 4 th, 2007 has the similar trend with the observation, showing that the samples 50-100 km away from the radar are most in accord with the observation, and that up to 72% of the samples within a distance of 100 km from the radar overvalue the snowfall, which should be noted and revised in operational application. © 2012 IEEE. Source

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