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Lian Q.-L.,Chinese Academy of Agricultural Sciences | Lian Q.-L.,Key Laboratory of Farm Building in Structure and Construction | Lian Q.-L.,China Agricultural University | Xin H.-B.,China Agricultural University | And 6 more authors.
Scientia Horticulturae | Year: 2013

Jasmonic acid (JA) plays a regulatory role in plant development such as tuber and corm formation and their responses to environmental stresses. The action of JA in regulating plant growth and stress responses often requires the elevation of endogenous levels by de novo synthesis. Allene oxide synthase (AOS), allene oxide cyclase (AOC) and 12-oxo-phytodienoic acid reductase 3 (OPR3) are the key enzymes involved in jasmonic acid biosynthesis in plants. Here, we isolated the AOS, AOC and OPR3 genes (GhAOS, GhAOC and GhOPR3) in full length from in vitro developing corms of Gladiolus hybridus. The subcellular localization analysis indicated that both GhAOS and GhAOC were chloroplast localization proteins whereas GhOPR3 was localized within the peroxisome. Real-time quantitative PCR showed that GhAOS, GhAOC and GhOPR3 genes were expressed constitutively in all organs with different levels having a relatively higher level in corms and cormels. Additionally, we observed that MJ treatments contributed to increasing the amount of three genes, mRNA level and endogenous MJ content thus promoting corm formation and enlargement. These results revealed that GhAOS, GhAOC and GhOPR3 were genes of significant importance and their expression contributed to JA biosynthesis thus playing an important role in corm formation and enlargement. © 2013 Elsevier B.V. Source


Qi F.,Chinese Academy of Agricultural Sciences | Qi F.,Xinjiang Academy of Agricultural Reclamation science | Qi F.,Key Laboratory of Farm Building in Structure and Construction | Zhu M.,Chinese Academy of Agricultural Sciences | And 3 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2015

Since 2003, Chinese agricultural and rural development has entered a golden period and a period of strategic opportunities. The report of 18th National Congress of Communist Party of China (CPC) proposes that the comprehensive goal of building a moderately prosperous society should be achieved in 7 years before 2020. To fulfill this objective, it is needed to make up the deficiency of agricultural development and accelerate development of agricultural modernization in China. However, in agricultural production, there are still a series of prominent contradictions and challenges between production resources and resource needs, between the product quantity and structure, between costs and benefits, between population and labor force, between infrastructure and natural disasters, and so on. All of these force the government to strength further the agricultural foundation, transform development pattern into a new path of intention-type agricultural development. One of primary tasks of China's modernization construction is to promote agricultural modernization. Agricultural engineering provides important technology support and substantial guarantee for the construction agricultural modernization. Recently, the improvement of agricultural engineering technology is increasingly correlated with development of agricultural modernization in China. According to the new strategy about promoting collaborative development of informationization, industrialization, urbanization and agricultural modernization (hereafter referred to as Four modernizations synchronization), agricultural modernization is involved in a more complicated giant social system, and the complexity, dynamics, openness and heterogeneity of the system are in accelerated growth. As a core element of China's agricultural modernization, agricultural engineering cannot develop well within its own isolated field. To be able to playing a better role and realizing win-win situation, the relationship and interaction between agricultural engineering and other systematical components have to be revealed in agricultural modernization. Based on the study about Chinese characteristic modern agriculture construction path, in combination with the theory, principle and methods of organized system and advanced productivity establishment, this study analyzed the systematic target and structure of China's agricultural modernization, and the status and function of agricultural engineering in the system and its relationship with other elements, structures and environment, in order to investigate the effect of the developing quantity, quality, momentum and structure of agricultural engineering on the developing quality and speed of agricultural modernization. The results showed that the development of agricultural engineering was greatly influenced by the development environment of agricultural modernization that included the macroscopic targets and polices related with national economy and society. The development of agricultural engineering was also restricted by the factors such as technology, talents, finance and management system. Meanwhile, agricultural engineering could improve the quality of core factors affecting agricultural modernization development including nature, policies, and society environment. Additionally, agricultural engineering had a significant impact on the structure of Chinese agricultural modernization development and showed positive correlations especially with the composition of the labor, land and products. In a word, the development mode of China's agricultural engineering needs to be changed. The period of strategic opportunity should to be well captured. The initiative and coordinate development of agricultural engineering can speed up the transforming of the development of modern agriculture, and create better developing environment and more opportunities for itself. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved. Source


He Y.,Chinese Academy of Agricultural Sciences | Yan J.,Chinese Academy of Agricultural Sciences | Yan J.,Key Laboratory of Farm Building in Structure and Construction | Zhou L.,Chinese Academy of Agricultural Sciences | Zhou L.,Key Laboratory of Farm Building in Structure and Construction
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2016

As a light steel structure, plastic greenhouse is lighter in weight, shorter in service life, lower in cost, more sensitive to wind and snow load and less social effect than the industrial and civil building structures, such as masonry, reinforced concrete structures and even other light steel structures. Notable differences in features and characteristics between both structure designs are mainly as the follows. First, plastic greenhouse uses a flexible covering material (such as plastic film) which is far less intensive but more sensitive to the distribution and value of the wind and snow load. Its live load effect is much greater than the permanent load effect; therefore the design parameters (such as statistical parameters of resisting force and load effect ratio) of such structure are different from building structure. Second, greenhouse's parts can be removed, transported and reassembled, so the defects in bars and nodes inevitably occurs, which has a greater impact on the structure tension performance. Third, greenhouse is relatively short in service life, almost 5-10 years. Forth, due to fewer operators and flexible covering material, the social effects of failure for the plastic greenhouse are far less than the industrial and civil building structures. Therefore, according to the characteristics of the greenhouse above, by referring to the "Unified standard for the structure reliability design", the security level of plastic greenhouse can be classified as the third level, and the target reliability index is 2.70, equivalent to the failure probability of 3.5‰. At present, although the codes have been designed for building structure for a long time, there are no appropriate codes for such light structure in China, which leads to waste and unreasonable results inevitably. So it is especially important to improve the design method of plastic greenhouse. This paper studies the simple load combination of dead load and wind load. The dead load obeys the normal distribution, and by statistical hypothesis testing, the mean value of dead load is 1.06 times the standard value of dead load in the "Specification for the load of building structure" with the variance of 0.074 of the standard value of dead load. The wind load obeys the distribution of extreme value I. According to the data of 3 s extreme wind speed from 1981 to 2010, which were recorded by the domestic representative cities' meteorological stations, the formula of probability distribution of the maximum wind load through the design reference period is deduced as statistical basis. According to probabilistic limit state design method, the parameter values are determined which are target reliability index, load effect ratio, coefficient of variation of load, coefficient of variation of resistance, security level, and so on; the combination of permanent load and wind load is taken as the example, the partial factor for nominal value of loads is calculated to determine the partial coefficients for loads in combination of dead load and wind load. The statistics of constant load and variable load are the averages of random variables, and load partial coefficients are derived from characteristic value, so the average value should be converted to the characteristic value, and then the scope of the partial coefficients is iterated successively. The value of partial coefficient for dead load is between 1.07 and 1.11, and that for wind load is between 0.89 and 1.22. According to the scope of the partial coefficients, the theoretical values of the partial coefficients for structural parts under different load effect ratio are obtained, using the principle of least squares. The value of partial coefficient for dead load is 1.1 and that for wind load is 1.0. Finally, by comprehensive consideration, the suggested values are given, namely the value of partial coefficient for dead load and wind load is 1.0. © 2016, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved. Source


Li M.,Chinese Academy of Agricultural Sciences | Li M.,Key Laboratory of Farm Building in Structure and Construction | Wei X.,Chinese Academy of Agricultural Sciences | Wei X.,Key Laboratory of Farm Building in Structure and Construction | And 4 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2014

The wall of a Chinese solar greenhouse can absorb heat during daytime and supply heat into the greenhouse during nighttime. It can help the solar greenhouse to maintain high indoor air temperature during winter nighttime with little or no supplemental heating. The brick wall is one of the popular walls. However, after a long period of use, walls have the bad performance on heat insulation and sealing. To solve the problems, we proposed to thicken the brick wall with foam cement to decrease its heat loss and keep the heat in the wall as much as possible. Then, the stored heat that the wall can supply during the nighttime can be increased. In this study, a solar greenhouse with the brick wall, which was composed of 120 mm thick brick, 100 mm thick polystyrene board, and 240 mm thick brick (from indoor to outdoor), was used as the control greenhouse. The test greenhouse had same structure and management with the control greenhouse, but its brick wall was thickened with 200 mm thick foam cement on the outdoor side. This wall was defined as the transformed wall. The heat insulation and supply performances of the two solar greenhouses' walls were compared based on the data collected in a typical sunny day and a cloudy day. As for the heat insulation performance, the outdoor surface temperatures of the brick wall and the transformed wall were (2.8±0.9) and (0.8±0.2)℃ higher than the outdoor air temperature, respectively, in the nighttime of the sunny day. The maximum heat flux in the foam cement was about 9% of that on the outdoor surface of the brick wall. A similar phenomenon was also observed in the nighttime of the cloudy day. The results indicated that thickening the brick wall with foam cement could decrease the heat loss of the wall and keep more heat in the wall. As for the heat supply performance, the indoor surface temperatures of the brick wall and the transformed wall were (1.5±0.5) and (2.4±0.2)℃ higher than the outdoor air temperature, respectively, in the nighttime of the sunny day. The results indicated that, by preventing wall from losing heat to the outdoors, the foam cement layer of the transformed wall could increase the amount of heat supplied into the greenhouse during nighttime. On the cloudy day, the indoor surface temperature of the brick wall was lower than the indoor air temperature. However, the indoor surface temperature of the transformed wall was (0.3±0.2)℃ higher than the indoor air temperature during the period from 17:30 to 08:00 in the next day. It indicated that the brick wall had been absorbing heat from the indoor air all through the day. The results further confirmed that the foam cement layer of the transformed wall could increase the heat insulation performance of the wall. As a result, the indoor air temperatures of the control greenhouse during night time of the sunny day and cloudy day were (1.3±0.6) and (0.8±0.3)℃ lower than those of the test greenhouse, respectively. After all, it is concluded that thickening the brick wall with foam cement on the outdoor side can improve its heat insulation and supply performance. ©, 2014, Chinese Society of Agricultural Engineering. All right reserved. Source


Li M.,Chinese Academy of Agricultural Sciences | Li M.,Key Laboratory of Farm Building in Structure and Construction | Zhou C.,Chinese Academy of Agricultural Sciences | Zhou C.,Key Laboratory of Farm Building in Structure and Construction | And 7 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2016

Soil wall of the Chinese solar greenhouse (hereafter referred to as "solar greenhouse") has problems of occupying large area and damaging the cultivation land. The simplification of soil wall, which means decreasing the thickness and soil use of the soil wall, becomes very important. The purpose of this study is to develop simplification methods of soil wall. A simplification wall with less soil use was proposed based on the measured temperature of soil wall and analysis of feasibility of those methods. The tested solar greenhouse was located in Yongqing county, Lanfang city, Hebei province (116°44' E, 36°27' N). It is 50 m long and 10 m wide. The top and bottom thicknesses of the soil wall were 2.0 and 5.3 m, respectively. Its average thickness was 3.6 m. The test period was from Dec. 01, 2013 to Mar. 30, 2014. During that time, the tested solar greenhouse was used to growing cucumber with surface irrigation. The heat insulation sheet of the solar greenhouse was rolled up and down at 8:30 am and 5:00 pm daily, respectively. The wind vent was open if the indoor air temperature was high during daytime. The indoor and outdoor air temperatures, solar irradiating on the inner surface of the wall, the temperatures in the soil wall and indoor soil were measured continuously at a time interval of 10 min. The data collected in a typical cloudy day ( 08:30 am of Dec. 29, 2013 to 08:30 am of Dec. 30, 2013) and a typical sunny day (08:30 am of Jan. 16, 2014 to 08:30 am of Jan. 17, 2014) were used to study the heat transfer pattern of the soil wall. Based on the measured temperature in the soil wall, the soil wall can be divided into heat storage layer and heat insulation layer. The heat storage layer had large temperature fluctuation and can be used for storing heat during daytime and release heat into the solar greenhouse during nighttime. The temperature of the heat insulation layer was lower than that of the heat storage layer and mainly used to prevent the heat in the heat storage layer from losing. Under the test conditions, the thicknesses of heat storage and insulation layers were 47 cm and 313 cm, respectively. Considering that the heat resistance of the heat insulation layer equals that of 7 cm polystyrene board, a composite wall with 7 cm polystyrene board and 47 cm rammed soil in the direction from exterior to interior was proposed. The results showed that under same conditions, the differences between the measured inner surface temperature of the soil wall and the simulated inner surface temperature of the composite wall was less than 5% in both sunny and cloudy days. The application of the polystyrene board can reduce the thickness and occupied area of soil wall by 85.0% and 89.8%, respectively in comparison with the conventional soil wall. On the other hand, the heats released by the indoor soil during the nights of sunny and cloudy day were 1.3 and 2.9 times more compared to those released by the soil wall. According to the simulation results, by increasing the 20 cm surface soil temperature from 17.0℃ to 23℃, the heat released by the indoor soil during nighttime were more than the measured heat released by both soil wall and indoor soil. In this case, the soil wall can be replaced by the wall build with thermal insulation material only. The thickness of soil wall can be further decreased. We concluded that the soil wall can be simplified by the following methods: 1) building its heat insulation layer with thermal insulation material, or 2) building the wall with thermal insulation material and increasing the indoor soil temperature. © 2016, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved. Source

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