Table of Content

15 January 2019, Volume 21 Issue 2

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Strategic Choice of Chinas Forage Industry Development Under Reverse Globalization

SHI Zizhong1, WANG Mingli1*, LIU Yazhao2

2019, 21(2):  1-8.  DOI: 10.13304/j.nykjdb.2018.0253

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With the prevailing of reverse globalization trend of thought and trade protectionism, it is of important significance to explore the influence of possible trade friction on forage industry, and clarify the development strategy of forage industry under this background. This paper analyzed the development trend of Chinas forage industry. In recent years, the forage production volume was larger, demand for forage products was on the rise. The price of homegrown forage was declining. The growth rate of import forage products was slackening, while the demand for forage products produced in United States of America was still bigger. In short term, the possible trade friction would affect the domestic forage market and development of dairy industry. In the long term, it might become opportunities for developing domestic forage industry, and promoting its rapid development. At the same time, it would intensify the competitive strength of import market. The paper suggested that repositioning agricultural production system, highlighting the strategic position of forage industry, supporting the rapid development of forage industry, accelerating the commercialization process of forage products, focusing on the international forage market, promoting the diversification of forage import market, establishing the forage reserve system, and expediting the circulation of forage products.

Research Progress on Plant Three-dimensional Reconstruction Based on Multi-view Images

ZHOU Jingjing1,2,3, GUO Xinyu2,3, WU Sheng2,3, DU Jianjun2,3，ZHAO Chunjiang2,3*

2019, 21(2):  9-18.  DOI: 10.13304/j.nykjdb.2018.0391

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Rapid reconstruction of plant three-dimensional structure and three-dimensional visual analysis of crop morphological structure, growth process and phenotype measurement are hot and difficult points in digital plant and crop breeding research. This paper summarized the research status and the mainstream technology of plant three-dimensional reconstruction, and classified and compared the methods, principles and technical advantages of various technologies. The research progress, technical principle and related hardware and software system platform of multi-view image three-dimensional reconstruction method SFM and MVS were emphatically introduced, and the application progress of multi-perspective image three-dimensional reconstruction in plant three-dimensional reconstruction in recent years were analyzed, the multi-perspective image three-dimensional reconstruction method had the advantages of low cost of data acquisition, high precision of point cloud acquisition and high quality of plant three-dimensional reconstruction. At the same time, the paper also pointed out the shortcomings of this technology and its future development trend, expected to provide useful reference for the development of plant three-dimensional reconstruction technology, the study of plant phenotypic omics and the development of low-cost and high-throughput equipment.

Research Advance on Drought Stress Response Mechanism in Plants

WANG Kaiyue, CHEN Fangquan, HUANG Wuxing*

2019, 21(2):  19-25.  DOI: 10.13304/j.nykjdb.2018.0115

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Drought stress is one of the major limitations to plant growth and development. Drought can lead to osmotic imbalance, damage of membrane system, decrease of respiration rate and photosynthesis rate, etc. adverse reaction. It not only hinders plant growth and metabolism at different stages, but also affects crops to achieve good quality and high yield. In the interaction between plants and external environment, plants will build drought response, such as changing the structure of plant root system and leaf blades, composition of metabolites and expression of drought-resistant genes to resist drought stress. The paper reviewed the research progress in the mechanism of plant response to drought stress from phenotypic level, physiological level and molecular level. The response of drought stress in phenotypic mainly included the structure change of root system and leaf. The response of drought stress to physiological was mainly reflected in photosynthesis, osmotic regulation, antioxidant metabolism and hormone, etc.. The paper elaborated in detail the molecular mechanism of plant drought stress response and regulatory and functional genes involved in drought stress, discussed the existing problems and look forward the research prospect.

Function of Calcium Dependent Protein Kinase 34 in Grain Starch Synthesis of Wheat (Triticum aestivum L.)

XU Mengjun, GAO Tian, WANG Pengfei, LI Gezi, KANG Guozhang*

2019, 21(2):  26-33.  DOI: 10.13304/j.nykjdb.2018.0173

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Calcium-dependent protein kinases play important roles in regulating growth, development and biological synthesis in higher plants. In this study, the function of a wheat calcium-dependent protein kinase, TaCPK34, in regulating the starch synthesis was identified using the barley stripe mosaic virus-virus induced gene-silencing (BSMV-VIGS) technique under field conditions. Our data indicated that expression levels of TaCPK34 gene in BSMV-TaCPK34-infected wheat plants were significantly inhibited by 63.8%～97.8% compared to those in BSMV-GFP-infected wheat plants (negative control) at 15 d, 20 d, 26 d and 30 d after virus inoculation. Starch content, and grain weight, grain length and width in BSMV-TaCPK34-infected wheat plants were also decreased significantly. Scanning electron microscope observation showed that morphology and number of starch granules in grains of BSMV-TaCPK34-infected wheat plants became looser and fewer compared to those of BSMV-GFP-infected wheat plants. These suggested that TaCPK34 could function in regulating starch synthesis of wheat.

Salt Tolerance of Different Peanut Varieties and Na+ Uptake Dynamic Characteristics

ZHANG Guanchu1,2, ZHANG Zhimeng1*, CI Dunwei1, DING Hong1, YANG Jishun1, SHI Xiaolong1,3, TIAN Jiaming1,3, DAI Liangxiang1*

2019, 21(2):  34-40.  DOI: 10.13304/j.nykjdb.2018.0041

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In order to explore the relationship between Na+ uptake dynamics and salt tolerance in different peanut varieties (HY20, HY25 and HY36) , this paper carried out hydroponic experiments to investigate the relationship between dry matter accumulation, Na+ uptake dynamics, Na+ absorption rate, Na+ rejection rate and salt tolerance of different peanut seedlings under different salt stress concentrations. The results showed that Na+ uptake dynamics in peanut could be divided into 2 absorption phases: high affinity and low affinity. Under low salt stress, peanut Na+ affinity constant (Km) was small, and the mean value of Na+ exclusion rate was about 85%. Under high-salt stress environment, the Km value and Na+ maximum absorption rate (Vmax) was large, and Na+ rejection rate was low. Under low salt stress, the absorption rates of Na+ in HY20, HY25 and HY36 were all small, while Na+ exclusion rate was high with slow Na+ accumulation, so the salt stress was less harmful. Under high salt stress, the Na+ absorption rate of HY20 was higher than that of HY25 and HY36. But the Na+ exclusion rate in HY20 was lower than that in HY25 and HY36. Therefore, under high salt stress, high Na+ absorption rate and lower Na+ exclusion rate might be the main reason for the salt tolerance in HY20 was weaker than that of HY25 and HY36.

Effects of Cutting Type and Diameter on the Rooting of Forsythia suspensa

LU Ruike1, GAO Xuefei2, LIU Lingdi1*, WEN Chunxiu1, XIE Xiaoliang1*, TIAN Wei1, JIA Dongsheng1, LIU Ming1, OUYANG Yanfei1

2019, 21(2):  41-45.  DOI: 10.13304/j.nykjdb.2018.0552

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In order to improve the survival rate of Forsythia suspensa cuttings and ensure the quality of seedlings, this paper studied the effects of cutting type and cutting diameter on the rooting. The results showed that the rooting rate of Forsythia suspensa stabilized after two months. And the rooting rate of bearing shoots was higher than vegetative shoots. The order of rooting rates of vegetative shoots and bearing shoots in different diameters were all fine> middle> thick, and the total root number of cuttings in different specifications decreased in order of T2 (middle vegetative shoot), T4 (thick bearing shoot), T1 (thick vegetative shoot), T6 (fine bearing shoot ), T5 (middle bearing shoot ), T3 (fine vegetative shoot ). While the order of the length of the longest adventitious root of cuttings in different specifications was T3>T5>T4>T2>T6>T1, and the order of the diameter of the longest adventitious root of cuttings in different specifications was T6=T3>T5=T4=T2>T1, which indicated cutting type had sigmificant effect on rooting of Forsythia suspensa.

Cloning of a Novel Laccase Gene From Humicola insolens Y1 and Its Heterologous Expression in Pichia pastoris

ZHANG Lijie1,2, XU Xinxin2, TIAN Jian2, CHU Xiaoyu2*, ZHU Baocheng1*, WU Ningfeng2

2019, 21(2):  46-53.  DOI: 10.13304/j.nykjdb.2018.0196

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Laccase is a copper-containing polyphenol oxidase, which has potential industrial value in the degradation of organic pesticide residues and lignin. In this study, the laccase gene Lac1 was isolated from a Humicola insolens Y1. The 1 803 bp DNA of Lac1 encoded a mature protein with 600 amino acids. The deduced amino acid sequence was aligned with available protein sequences held in the GenBank, the results showed that the highest similarity was 71% which was the polyphenol oxidase sequence from Chaetomium globosum CBS 148.51 (XP_001228806). The recombinant vector pPIC9r-Lac1 was constructed and transferred into Pichia pastris to integrate into the yeast genome and the recombinant laccase was secreted expression. It was confirmed by the PCR and SDS-PAGE. In 3 L fermentation, the expression of Lac1 protein reached 3.79 mg/mL, and the enzyme activity reached 1.3 U/mL. The analysis of enzymatic properties showed that the optimum temperature was 65℃, the optimum pH was 4.5, and the relative activity of enzyme was above 70% in pH 6～11.

Remote Sensing Classification of Crops Based on the Change Characteristics of Multi-phase Vegetation Index

WEI Pengfei1,2,3, XU Xingang2,3, YANG Guijun2,3, LI Zhongyuan1, WANG Jianwen2,3, CHEN Guo1,2,3

2019, 21(2):  54-61.  DOI: 10.13304/j.nykjdb.2018.0063

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GF-1/WFV remote sensing image has higher temporal and spatial resolution. It has obvious advantages to carry out crop classification survey using multiphase images. This paper took Yingshang county of Anhui Province as the study area and extracted main crop classification based on the GF-1/WFV satellite remote sensing image data from May to September 2017. Firstly, through analyzing the sequential variation characteristics of major crops typical vegetation index NDVI, EVI and WDRVI in the study area, made clear the response characteristics of different crops in each time. Then, based on sensitive VI changes of crops in different time phases, the paper constructed decision tree classification model, and successfully extracted the spatial distribution of 4 major crops: corn, rice, soybean and sweet potato in the study area. The results showed that the overall accuracy was 90.9%, and Kappa coefficient was 0.895. At the same time, this paper used the maximum likelihood method, supported vector machine (SVM) for crop classification. The comparison results showed that the maximum likelihood method was the worst, and the support vector machine was second, and the decision tree classification method was the best. Above results indicated that using the remote sensing image data of time series of multi-phase combined with the feature of crop vegetation index, the classification method of decision tree could effectively improve the accuracy of crop classification.

Research Advances on Cereal Crops Phytomer

WANG Yongjian1,2,3,4, WEN Weiliang1,2,3, GUO Xinyu1,2,3*

2019, 21(2):  62-70.  DOI: 10.13304/j.nykjdb.2018.0056

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Phytomer is a basic component unit of cereal crops morphology. It is an extension of modular theory in recognition of morphological structure of gramineous crops, and also one of the research scales of the structure and function of gramineous crops. Based on the modularization property of node unit structure and function, this paper summarized the concept of crop node unit of gramineous crops and its application in studying crop structure and function. Firstly, the development process of nodal unit concept was introduced from the concept of nodal unit. Then, from the perspective of structure and function, the research progress of gramine-based crops was summarized. The study of structure was mainly illustrated from 3 aspects: topological structure, geometric structure and morphological construction. Functional studies were mainly analyzed from the aspects of photosynthetic product distribution, growth period prediction and development process. Finally, the paper prospected the future research on structure and function of gramineous crops based on nodal units in the aspects of standardization, geometric structure reconstruction, phenotypic data extraction and microstructure.

Fuzzy Comprehensive Evaluation method Calculation of Correlation Degree and Module Division of Agricultural Machinery parts

LUO Shilin1,2, HE Miao1, LI Jianyao1, DU Hao1, LU Shiqing1, YANG Yan1*

2019, 21(2):  71-81.  DOI: 10.13304/j.nykjdb.2018.0004

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In order to achieve rapid product design and innovative design, the existing products could be divided into modules, and then through modular combinations to combine as many kinds of products as possible with limited resources followed by module combinations. This design method is called modular design, and it is also the focus of current research. By using reasonable and practical methods to divide the existing products, rapid design and innovative design could be prepared, and then the module partition was realized by different algorithms. The rationality of the evaluation model and the partition result was verified by observing and comparing the partition results.

Experimental Study on Mechanical Properties of Pellet Feed

ZHANG Nan, LIU Jing, NIU Zhiyou*, SHI Lijun, LIU Zhaoxia

2019, 21(2):  82-90.  DOI: 10.13304/j.nykjdb.2018.0055

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In order to explore the mechanical properties of pellet feed, this paper took 3 types of formula feed produced by feed industry for pig, poultry and fish as experiment samples, and conducted axial compression, radial compression and shear tests, respectively. Under the 3 different test methods, the ultimate strength of aquatic formula feed was the highest, followed by poultry compound feed, and pig formula feed was the lowest. With the increase of aspect ratio, the ultimate strength of radial compression and shear did not change much, and the ultimate strength of axial compression tended to decrease with the increase of aspect ratio. With the increase of moisture content, the ultimate strength of pellet feed increased first then decreased, and the ultimate strength had the maximum value. Feed category, test method and moisture content had significant effects on ultimate strength. Adopting Design-expert response surface method, this paper obtained the response surface relationship among target load, dwell time and powder content rate. The results showed that there was a linear relationship between the powder content of pellet compound feed, payload and dwell time. The payload and dwell time had a significant effect on powder content, and the effect of payload on content of powder was more significant than that of dwell time.

Research Advances on Coelomocyte of Echinodermata

REN Yuan1,2, LI Qiang2*, WANG Yinan2, LI Zhen2

2019, 21(2):  91-97.  DOI: 10.13304/j.nykjdb.2018.0065

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Echinodermatas are the second largest family of deuterostomes in the ocean after chordate. Coelomic cells are an important part of the immune defense of echinodermatas, and possess phagocytic encapsulation, oxidative killing, wound repair and agglutination, which play crucial functions in immune responses. This paper summarized the classifications, functions and origins of echinodermatas′ coelomocytes, such as starfish, sea urchins and sea cucumbers, in order to provide references for the cellular immune defense mechanisms of echinodermatas.

Study on Extraction Process of Sodium Alginate in Sargassum kjellmaniamum by Complex Enzymes Method

LI Xiao1, GAO Chao2, WANG Ying1*, MU Haijin2, JIANG Xiaodong1, LIU Tianhong2

2019, 21(2):  98-103.  DOI: 10.13304/j.nykjdb.2018.0198

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Sargassum kjellmaniamum is a warm temperate brown algae specially located in western North Pacific Ocean and mainly distributed along the Yellow Sea and Bohai Sea coast of China. It is of higher economic and ecological value and can be used as raw material for extracting marine algae. This study extracted sodium alginate from S. kjellmanianum by compound enzymes method (cellulase, pectinase and papain). On the basis of single factor experiment, including enzyme adding quantity, extracting temperature, pH, extract time, the orthogonal experiment was conducted to optimize the extraction process. Results showed that the optimal extraction technology including adding 3% cellulase, 3% pectinase, 1% papain, the solid to liquid ratio was 1∶20, 55℃ and pH 4 for 105 min. Sodium alginate was manufactured through digestion, decoloration, calcium analysis, acidification, and alcohol precipitation, etc. technology. The extraction rate of sodium alginate could reach 16.82%. These results provided effective technological approaches for high value processing of S. kjellmaniamum.

Effect of Cry1Ie Bt Maize on Carbon Source Metabolism of Rhizosphere Microorganisms

LIANG Jingang1,2, XIN Longtao2, LUAN Ying2, SONG Xinyuan3, ZHANG Zhengguang2*

2019, 21(2):  104-110.  DOI: 10.13304/j.nykjdb.2018.0133

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With the increase of genetically modified (GM) crops area, their biosafety for soil ecosystems has become a controversial issue. This paper compared the functional diversity of rhizosphere microbial communities between GM Bt maize IE09S034 and its non-GM parental maize Zong31 by Biolog ECO microplate. Results indicated that there was no difference between IE09S034 and Zong31 in the functional diversity of microbial communities in rhizosphere soil. Besides, year and plant growth stage had stronger effect than cultivar. It was concluded that GM maize IE09S034 did not alter the functional diversity of microbial communities in rhizosphere soil.

Influences of Water-saving and Nitrogen-reducing on Quality, Yield and Water-Nitrogen Use Efficiency of Protected Tomato

LIU Zhongliang1, GU Duanyin1, ZHANG Yanyan1, JIAO Juan1, GAO Junjie1*, LIU Shiqi2, TIAN Xiaofei3

2019, 21(2):  111-119.  DOI: 10.13304/j.nykjdb.2018.0302

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In order to explore the appropriate water-nitrogen management pattern for tomato substrate culture in solar greenhouse, this paper studied the effects of water and nitrogen interactions on photosynthetic properties, quality and yield of protected tomato, taking tomato cv. STP-F318 as test material, fixing the quantities of phosphate and potash fertilizer application, designing 3 drip irrigation levels(W1~W3:4 646.25 mm/hm2, 3 097.50 mm/hm2 and 1 548.75 mm/hm2) during growth period and 6 nitrogen fertilizer grades(F1~F6: 572.42 kg/hm2, 542.30 kg/hm2, 512.17 kg/hm2, 482.04 kg/hm2, 451.91 kg/hm2 and 0 kg/hm2) , and taking the local farmers conventional irrigation and fertilization managements (7 650.00 mm/hm2, 600.00 kg/hm2) as the contrast(CK). The results showed that suitable water-nitrogen interaction could significantly increase SPAD value and net photosynthetic rate of leaf, and leaf SPAD value was the largest under W1F4 treatment, reaching 44.83; and net photosynthetic rate was the largest, reaching 16.69 μmol/s2·m under W1F2 treatment. Meanwhile, all the treatments had improved the fruit quality. The highest Vc content was obtained under W1F3 treatment, reaching 30.46 mg/100 g FW, which was 17.61% higher than that of the CK treatment, and there were significant differences between W1F3 treatment and the other treatments. The contents of lycopene and Vc showed the same changing trend as 5.21~7.80 mg/100 g·FW. While the contents of organic acid showed a decreasing trend compared with that of the CK treatment. The sugar-acid ratio of W3F2, W1F1, and W1F3 treatments were 8.25, 8.26, and 8.85, respectively, all with better tastes. As for the yield, W1F2 treatment had the highest yield of 170 985.48kg/hm2, 27.73% higher than that of the CK. The nitrogen agronomic efficiency (NAE) and water use efficiency(WUE) were the highest under W1F4 and W3F4 treatments, respectively, reaching 87.34% and 96.64 kg/mm·hm2. Comprehensive analysis deemed that water and nitrogen interaction could significantly improve tomato quality, increase its yield and water-nitrogen use efficiency. During the growth period, drip irrigation quota 4 646.25 mm/hm2, nitrogen fertilizer amount 542.30 kg/hm2 was the optimum management pattern of water and nitrogen fertilizer under substrate culture of tomato.

Effects of GA3 and TDZ on the Astringent Taste of ‘Jumeigui’ Grape Berry Skin

HUANG Haina, CHENG Dawei, GU Hong, ZHANG Yang, GUO Xizhi, CHEN Jinyong*

2019, 21(2):  120-132.  DOI: 10.13304/j.nykjdb.2018.0210

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In order to explore the effects of exogenous gibberellic acid (GA3), thidiazuron (TDZ) and their combination with different concentrations on the astringency of ‘Jumeigui’ grape berry skin. Taking ‘Jumeigui’ grape as material，grape clusters were evenly dipped with GA3 (T1: 12.5 mg/kg GA3; T2: 25 mg/kg GA3; T3: 50 mg/kg GA3), TDZ (T4: 1.25 mg/kg TDZ; T5: 2.5 mg/kg TDZ; T6: 5 mg/kg TDZ) or their combination (T7: 25 mg/kg GA3+2.5 mg/kg TDZ) during the early stage of fruit physiological drop and the early stage of the fruit enlargement. Astringent substance content was analyzed regularly. The tannin distribution of fruit was observed by paraffin section. The results showed that tannin cells in the peel treated with different concentrations of GA3 or the combination were sparsely distributed. While tannin cells in the peel treated with different concentrations of TDZ were densely distributed, with more layers and deeper colors. The content of soluble tannin, insoluble tannin, total tannin, flavonoids, and total phenol of ‘Jumeigui’ grape fruit skin treated with different concentrations of GA3 or combination were less than that of control, and the anthocyanin content was higher than that of control. However, the content of soluble tannin, insoluble tannin, total tannin, flavonoids, total phenol and anthocyanin of ‘Jumeigui’ grape fruit skin treated with different concentrations of TDZ were all higher than that of control. The result of principal component synthetic evaluation showed that the order of the astringent taste compounds of eight treatments was T6＞T4＞T5＞CK＞T7＞T2＞T3＞T1. It showed that GA3 treatments had the best effect on reducing the astringency of grape peel, and the concentration of 12.5 mg/kg GA3 treatment was the best, followed by the mixed solution treatment. TDZ treatments were not conducive to reducing the astringency of grape peel. The above results provided a theoretical basis for improving the astringency of fresh grape berries by using plant growth regulators.

Impact of Decomposed Wheat Straw on the Quality of Flue-cured Tobacco

JIA Guotao§, YANG Xinling§, YANG Yongfeng, WANG Baolin*, SHEN Hongtao, WANG Genfa, LIU Xiangzhen, ZHANG Shuwei, LIU Chao, YAO Qian, ZHAO Sensen, NIU Yangyang

2019, 21(2):  133-140.  DOI: 10.13304/j.nykjdb.2018.0538

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In order to explore the effect of decomposed straw on the quality of flue-cured tobacco, this paper took “Zhongyan 100” as test material, set up 4 treatments of different decomposed straw dosages, including 0 kg/hm2 （CK）, 3 750 kg/hm2（T1）, 7 500 kg/hm2（T2）, 11 250 kg/hm2（T3）; and studied the effects of decomposed straw on chemical composition, aroma content and sensory quality of flue-cured tobacco by field trials. The results showed that the ratios of reducing sugar and total sugar of T2 and T3 were 5.06% and 4.94% higher than that of the CK, respectively; sugar-nicotine ratio of T3 was 23.39% higher than that of the CK; potassium contents of T2 and T3 were 22.26% and 16.12% higher than that of the CK. The total amount of aromatic substance in T2 was 675.20 μg/g increased by 32.36% than that of the CK, and the contents of neutral aromatic substance in all treatments were significantly higher than that of the CK. The aroma quality, aroma quantity, concentration, stray air and combustibility of T2 were the highest, and total sensory quality score of T2 was the highest at 62.71, followed by T3 at 62.43. On the whole, the application of decomposed straw could improve the quality of flue-cured tobacco. The best application quantity was 7 500 kg/hm2. Those results provided reference basis for producing flue-cured tobacco with strong-flavor of special type in Henan province.

Influenes of Exogenous Melatonin on Antioxidant and Photosynthetic Characteristics of Tobacco Seedlings Under Salt Stress

LI Meng, CHEN Dong, LI Xiuni, LI Linlin, WANG Ronghao, SHI Xiangdong*

2019, 21(2):  141-147.  DOI: 10.13304/j.nykjdb.2018.0291

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Melatonin (MT) is a small molecule substance widely found in high plants and plays some roles in the growth and development of plants and enhances stress resistance. In order to clarify the physiological mechanism of exogenous melatonin in tobacco seedlings under salt stress, this study took tobacco cultivar K326 as the research object, and adopted water culture method to analyze the anti-oxidation and photosynthetic characteristics of tobacco seedlings under different treatments by applying different concentrations of exogenous melatonin. The results showed that the leaf moisture content of tobacco seedlings decreased after salt stress treatment, which destroyed the normal physiological state and photosynthesis process. After treated with different concentrations of exogenous melatonin, the leaf moisture content recovered and the chlorophyll content increased. Proline content increased significantly, peroxidase activity significantly increased, hydrogen peroxide and malondialdehyde content decreased significantly, photosynthetic efficiency increased, and melatonin treatment had a significant concentration effect, the best effect at 100 μmol/L, which provided a theoretical basis for the study of melatonins mechanism of action.

Research on Lignin Degradation and Humus Formation During Composting

YANG Chaoyuan, LIU Guotao*, LI Weiyu, LI Lei, XIA Xuan, LI Shibo

2019, 21(2):  148-154.  DOI: 10.13304/j.nykjdb.2018.0159

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Aerobic composting, as one of the technologies for treating organic solid waste, can simultaneously realize the safe disposal, minimisation and recycling of wastes. The abundant contents and complex structure of lignin in composting materials is an important factor limiting the rapid humification rate. The stable humus formed during composting is a good soil remediation and amendment. Enhancing lignin degradation, while promoting rapid humus formation is the key to improve composting efficiency and compost quality. This paper reviewed the effects of microorganism, pretreatment methods and additives on lignin degradation; summarized the characteristics and forming process of humus, appling studies on humus and relationship between humus formation and lignin degradation. The paper also put forward the following aspects for research: ① ligninase catalyzing mechanism, gene structure and expression regulation mechanism of ligninase; ② pretreatment technology of lignocellulose with high efficiency and low consumption; ③ structural characteristics of compost humus and its mechanism of soil nutrition regulation, so as to provide references for achieving rapid organic matter humification and compost humus resource utilization.

Effects of Storage Temperature and Time on Test Values of Potassium in Air-dried Soil

ZHU Dandan, ZHANG Jianglin, ZHAN Liping, CONG Rihuan, ZHANG Wenjun, LI Xiaokun*

2019, 21(2):  155-162.  DOI: 10.13304/j.nykjdb.2018.0076

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In order to correctly evaluate the timeliness of soil potassium (K) test value, this paper studied the dynamic changes of potassium test value in soil samples dried by different forms through culture experiment under 4 types of storage temperature (room temperature, 4℃ low temperature, 25℃ constant temperature, 60℃ dry incubator). The results showed that: Storage temperature and time could significantly affect the test values of different K forms. Under different storage temperature, along with the extension of storage time, the test value of water soluble K was different from that of before culture (the initial value). Under room temperature, the variation relatively to the initial value was smaller, and it was greater under 4℃ low temperature and 60℃ dry incubator. The test value of exchangeable potassium under 60℃ dry incubator had larger variation relatively to the initial value; while the variation under room temperature and 25℃ constant temperature were smaller. The test value of nonexchangeable K had smaller variation under 4℃ low temperature, and it had a larger variation than the initial value under room temperature, 25℃ constant temperature and 60℃ dry incubator. The transformation of different K forms was significantly affected by storage temperature and time. The water soluble K, exchangeable K values were increased under 4℃ low temperature; and there was a dynamic balance between water soluble K and exchangeable K when the soil samples stored at room temperature and 25℃ constant temperature conditions; with the extension of storage time, the nonexchangeable K was converted into exchangeable potassium under 60℃ dry incubator for long period of time. In conclusion, storage temperature and time significantly affected air-dried soil K test value, and K test value had timeliness.

Variation Characteristics Analysis of Near-Surface Dust Horizontal Flux and Dust Fall Amount in Northeast of Ulan Buh Desert

LUO Fengmin, GAO Junliang, LIU Fang, LI Xinle, HUANG Yaru, GEGEN Batu, DUAN Ruibing, XIN Zhiming*

2019, 21(2):  163-169.  DOI: 10.13304/j.nykjdb.2018.0195

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It is of great significance to study the characteristics of sand-dust varied with height for revealing the distribution traits of sand-dust in the surface layer. This paper collected data of horizontal sand-dust fulx and dust fall amount from the dust observation tower within the height of 50 m, located in the northeast of Ulan Buh Desert; and studied the effect of regional protection forest on change features of sand-dust horizontal and vertical flux. The results indicated that: ① Both horizontal sand-dust flux and dust fall amount decreased along with the height increasing. The distribution characteristics of horizontal dust flux and dust fall amount with height accorded with power function inside of the shelterbelt, and the distribution characteristics of them accorded with exponential function outside of the shelterbelt. ② The horizontal dust flux and dust fall amount were positively correlated. They could be presented by linear functions. ③ Both horizontal dust flux and dust fall amount with wind speed presented a linear relationship.