Archive

10 July 2018, Volume 32 Issue 4 Previous Issue    Next Issue
---
Orginal Article


For Selected:

Download Citations EndNote Ris BibTeX

Toggle Thumbnails

Orginal Article

Select

Regulations of Plant Growth and Development by Cytokinins and Their Applications in Rice Production Zhikang LI, Dong YAN, Zhangyi XUE, Yibiao GU, Sijia LI, Lijun LIU, Hao ZHANG, Zhiqin WANG, Jianchang YANG, Junfei GU 2018, 32(4): 311-324.  DOI: 10.16819/j.1001-7216.2018.8027 Abstract ( )   HTML ( )   PDF (1066KB) ( )   Cytokinins (CTKs) play important roles in regulating crop morphology, physiology, and yield. In the development of crops, CTKs are the main factors controlling the uptake, translocation, and metabolisms of nutrients, especially for nitrogen. In this paper, we summarized the uptake, translocation and metabolism of nitrogen, and synthesis, translocation and signaling of cytokinins, with a focus on the coordination of CTKs and nitrogen in regulating root-shoot relationships and their influences on crop agronomic traits. Generally, the synthesis of trans-zeatin (tZ) and tZ riboside (tZR) was up-regulated by nitrogen in roots, and they are translocated to shoots, regulating the portioning and metabolism of nitrogen, influencing the photosynthetic characteristics and yield. In shoots, the synthesis of N6-(Δ2-isopentenyl)- adenine (iP) and iP riboside (iPR) were up-regulated by nitrogen, and they are translocated to roots by phloem, reducing the uptake and translocation of nitrogen, influencing the root morphology. Based on current knowledge, we further discussed the role of CTKs in coordinating source-sink relationships and improving grain filling. We also analyzed the influence of cultivation practices on metabolism of CTKs and its correlation with crop growth. At the same time, we also discussed the existing problems in the application of CTKs in rice production systems. We hope that it could provide valuable information for high yielding and high efficiency rice production.

Select

Mapping and Mutation Analysis of Stripe Leaf and White Panicle Gene SLWP in Rice Kunneng ZHOU, Jiafa XIA, Tingchen MA, Yuanlei WANG, Zefu LI 2018, 32(4): 325-334.  DOI: 10.16819/j.1001-7216.2018.7122 Abstract ( )   HTML ( )   PDF (1464KB) ( )   【Objective】Cloning and function analysis of chloroplast development-associated genes will lay a molecular basis for clarifying chloroplast function. 【Method】A stripe leaf and white panicle mutant, slwp, was isolated from an ethylmethylsulfone (EMS) mutagenic population of indica rice cultivar 9311. The phenotypic characteristics of slwp were analyzed by pigments determination and agronomic traits observation. The SLWP gene was identified by map-based cloning method. The gene expression was analyzed by the quantitative real-time PCR.【Result】The slwp mutant showed stripe leaf phenotype from two-leaf stage to heading and white panicle after heading accompanied by obviously decreased pigment contents compared with wild type. The slwp mutant was also featured with delayed heading and decreased plant height and yield and so on. Genetic analysis demonstrated that the mutant phenotype was controlled by a recessive nuclear gene. The SLWP gene was fine-mapped to a 0.91 Mb interval between markers C6-4 and N14 on the short arm of rice chromosome 6. Sequence comparison displayed that a single nucleotide substitution (G776A) in the coding region of ribonucleoside-diphosphate reductase small chain(RNRS1), which led to the amino acid change from Gly to Asp. The SLWP was allelic to St1, Gws and St-wp. We analyzed the mutant sites and phenotypes of the four alleles and summarized the effect of mutation on plant phenotypes and the difference between indica and japonica. In addition, expression analysis revealed that genes involved in chlorophyll biosynthesis were differently regulated, genes involved in the first and second steps of chloroplast differentiation were up-regulated, and genes involved in photosynthesis were down-regulated. 【Conclusion】We analyzed the effect of mutant sites in SLWP(RNRS1) gene on rice phenotypes. It deepens understanding for RNRS1 function and help to elucidate the molecular mechanism of chloroplast development.

Select

Isolation and Characteristic Analysis of Protein Kinase Promoter OsSRLp from Rice Qingguo WANG, Yingying WANG, Zhen LI, Jiaowen PAN, Yifan WANG, Yingxiu LI, Wei LIU 2018, 32(4): 335-341.  DOI: 10.16819/j.1001-7216.2018.7127 Abstract ( )   HTML ( )   PDF (545KB) ( )   【Objective】To study the construction and function of OsSRL, a typeⅠcasein kinase, 【Method】OsSRL and about 1600 bp up-stream of the gene named as OsSRLp were isolated using genomic DNA of rice Zhonghua 11. The regulatory elements of OsSRLp were analyzed using online software of PLACE, and the results showed that several key cis-elements which associated with reproductive process, signal and stress response were included. 【Results】The expression pattern analysis showed that OsSRL was constitutively expressed in different tissues of rice. The fusion expression vector of OsSRLp and GUS was constructed, and the vector was transformed into rice callus. After positive transgenic lines were obtained, the GUS activities were further detected, and the results showed that relative higher level expression was detected in spikelet, root and stem, as well as low expression levels in other rice tissues. The results indicated that OsSRLp possess constitutive activities with slightly variations in different rice tissues. 【Conclusion】 Combined with the characteristic elements and their potential functions of OsSRLp, the results implied that OsSRL and its promoter OsSRLp could participate in and regulate the development and reproduction progresses of plants.

Select

Genetic Transformation of Rice black streaked dwarf virus P7-1 Gene in Rice and Its Virus Resistance Analysis Pingping YUAN, Feng SUN, Haiping NI, Jiahui ZHU, Yijun ZHOU, Xuanli JIANG, Qiufang XU 2018, 32(4): 342-348.  DOI: 10.16819/j.1001-7216.2018.8014 Abstract ( )   HTML ( )   PDF (676KB) ( )   【Objective】The purpose of this study is to determine whether Rice black streaked dwarf virus (RBSDV) P7-1 is an important pathogenic factor related to infertility in rice and to analyze the resistance of the P7-1 transgenic rice to RBSDV by overexpression of P7-1 in rice. 【Method】 RBSDV P7-1 gene was amplified from virus-infected plants by RT-PCR. The recombination plasmid pCAMBIA-1300-P7-1 was constructed and transformed to rice by Agrobacterium transformation. The fertility of transgenic plants was evaluated and the resistance of the transgenic rice plants to RBSDV was identified by artificial inoculation of virus. 【Result】The transgenic plants showed normal growth and fertility. The virus accumulation in the transgenic plants was significantly lower than the wild type at 7 days and 14 days after inoculation, but it was higher in some transgenic lines than the control at 28 days after inoculation. There were no significant differences in disease incidence between the transgenic plants and the wild type at 30 days after inoculation. 【Conclusion】 Overexpressing RBSDV P7-1 in rice does not affect the fertility. Transgenic rice had lower accumulation of virus in the early stage after RBSDV infection, but did not exhibit resistance to the virus at the later stage.

Select

Identification and Genetic Analysis of Thermo-sensitive Mutant osv15 in Rice Yuehan QI, Ruili LI, Fang WANG, Hongjia LIU, Keke YI, Cheng ZHU 2018, 32(4): 349-356.  DOI: 10.16819/j.1001-7216.2018.7131 Abstract ( )   HTML ( )   PDF (949KB) ( )   ：【Objective】The objective of the research is to identify and clone a new thermo-sensitive gene of rice, and to reveal the molecular mechanism involved in the process of chloroplast development and photosynthesis, providing theoretical support for photosynthetic efficiency breeding. 【Method】A yellow leaf mutant osv15 was obtained from rice cultivar Nipponbare (abbreviated as Nip) mutagenized by irradiation. The phenotypic, agronomic traits and genetic patterns of osv15 were analyzed in detail, and F2 population was constructed by crossing the mutant with Kasalath, and mutant individuals were selected to map the gene OsV15.【Result】The mutant osv15 exhibited etiolation at seedling stage, with only ten percent of the chlorophyll content of the wild type, declined photochemical efficiency and abnormal structure of chloroplasts under low temperature condition (22℃). As temperature rose, leaf color of the mutant regreened due to increased chlorophyll content, which recovered to sixty-eight percent of that of the wild type under higher temperature condition (30℃). In natural environment, osv15 showed leaf yellowing from seedling stage to maturity stage, and significant differences in plant height, tiller number, seed setting rate and so on. Genetic analysis revealed that the mutant phenotype of osv15 was controlled by a single recessive gene. The gene was located in the 84 kb region of chromosome 6, between molecular markers S4 and S5. Sequencing analysis in this region showed that Cpn60β1(LOC_Os06g02380) that encodes a putative chaperonin 60 beta precursor, carried a single base deletion in osv15.【Conclusion】osv15 is a new thermo-sensitive mutant, and Cpn60β1 may be the mutant gene.

Select

Dissection of Grain Yield Differences Between japonica Rice in Northeast China and in Japan Hong GAO, Nan JIANG, Guoyi LÜ, Yingjun XIA, Jiayu WANG, Jian SUN, Liang TANG, Zhengjin XU, Guomin SUI 2018, 32(4): 357-364.  DOI: 10.16819/j.1001-7216.2018.7098 Abstract ( )   HTML ( )   PDF (858KB) ( )   【Objective】 Breeding strategy of intersubspecific hybridization combined with utilization of ideal plant type has led to the variety replacement from Chinese high-yielding japonica varieties to the Japanese japonica varieties that ever dominated more than a century in northeast China. Here, we study the effects of hybridization between indica and japonica on japonica breeding in northeast China through feature comparisons of morphology, genetic and yield. 【Method】 The lineage proportion of indica was detected using subspecies-specific InDel and SSILP markers, the Cheng’s index and ratio of vascular bundle numbers, then their relationships with yield components were discussed. 【Result】The yield of japonica cultivars in northeast China increased 15.79% and spikelet number per panicle increased by 15.22% than Japanese japonica cultivars. The japonica-type allele frequency was significantly lower in japonica varieties in northeast China than in Japanese varieties; on the other hand a japonica-linous type was defined by Cheng’s index. A very significant negative correlation was observed between indica-type allele frequency with panicle number, and very significant or significant positive correlation with spikelet number per panicle, number of the primary rachis branches, number of grains on the primary rachis branches, number of secondary rachis branches, number of grains on the secondary rachis branches. 【Conclusion】The key to high yield of japonica cultivars in northeast China were to increase the spikelet number per panicle and reduced the number of panicles with the utilization of indica-type allele frequency, meanwhile, to maintain a high level of seed setting rate and 1000-grain weight.

Select

Protective Roles of Over-expression of OsXDH in Rice Seedlings Under High Temperature Stress Ruicai HAN, Ruqi SU, Jianlin WAN, Qizhang LONG, Yongjun ZENG, Xiaohua PAN, Qinghua SHI, Ziming WU 2018, 32(4): 365-373.  DOI: 10.16819/j.1001-7216.2018.7130 Abstract ( )   HTML ( )   PDF (975KB) ( )   【Objective】Xanthine dehydrogenase (XDH) is considered as a key enzyme in purine metabolism. This paper aims to reveal the physiological mechanism of XDH to relieve high temperature stress by analyzing the physiological indexes of rice seedling leaves differed in expression level of OsXDH under high temperature stress. 【Method】In this work, chlorophyll content, relative water content, soluble protein content, reactive oxygen metabolism, antioxidant enzyme activities, XDH activity, allantoin and allantoate contents were measured under high temperature stress in OsXDH over-expressed transgenic lines and wild type during seedling stage. 【Result】The results revealed that there were no significant difference between wild type and transgenic lines in all tested physiological parameters except XDH activity and ureides (allantoin and allantoate) content before high temperature stress. After high temperature stress for 5 days, compared with the transgenic lines, seedlings of wild type showed significantly decreased chlorophyll content, relative water content, soluble protein content, and antioxidant enzyme activities, but significantly increased contents of H2O2 and Malondialdehyde(MDA). As we know that chlorophyll content, relative water content, and soluble protein content all increased in transgenic lines and wild type after post-stress recovery, especially in transgenic lines. H2O2 and MDA content all decreased. For transgenic lines, these indexes were lower than those in wild type. The XDH enzyme activity and purine metabolites allantoin and allantoate contents in the wild type and transgenic lines were induced by high temperature. OsXDH over-expressed transgenic lines had significantly higher XDH enzyme activity and allantoin and allantoate contents compared with wild type throughout the process. 【Conclusion】XDH can effectively improve the tolerance of rice seedlings to high temperature stress by regulating the synthesis of ureides, compensating their antioxidant capacity and enhancing the activities of antioxidant enzymes.

Select

Effects of Reduced Slow-released Urea Combined with Conventional Urea Under Different Plant Spacing on Characteristics of Nitrogen Utilization in Mechanically-transplanted indica Rice Haiyue WANG, Changchun GUO, Yongjian SUN, Yinghong LI, Mingjin JIANG, Fengjun YAN, Yaozhu YIN, Yan HE, Hui XU, Zhiyuan YANG, Jun MA 2018, 32(4): 374-386.  DOI: 10.16819/j.1001-7216.2018.7092 Abstract ( )   HTML ( )   PDF (865KB) ( )   【Objective】To further study the effects of reduced slow-released urea combined with conventional urea under various row spacing on N accumulation at the main growth stages, N translocation (NT), N apparent use efficiency (NAUE), grain yield, and the correlations among these indexes of mechanically-transplanted rice. 【Method】Based on the previous research of high-yielding nitrogen application rate of 180 kg/hm2 (the ratio of slow-released urea and conventional urea was 7:3), three plant spacing (16, 18 and 20 cm, the row spacing was 30 cm) and four treatments of reduced slow-release urea (36, 66, 96 and 126 kg/hm2) combined with conventional urea rate of 54 kg/hm2 were conducted. 【Result】There were significant influences on the total nitrogen accumulation amount of the main growth stages, the nitrogen absorption amount of leaves and panicles at maturity stage, N translocation of filling stage, NAUE and grain yield of reduced slow-released urea combined with conventional urea and row spacing. The effects of reduced slow-released urea combined with conventional urea on grain yield and nitrogen absorption and translocation were significantly larger than that of row spacing. When the combined application rate was 150 kg/hm2 (slow-released urea and conventional urea application rates were 96 kg/hm2 and 54 kg/hm2, respectively) and the plant spacing was 18 cm that could facilitate N accumulation of main growth stage, enhance N accumulation amount of different organs at grain filling stage, and promote N translocation of stem sheath and leaves, which further improve N increment of panicle(107.58 kg/hm2), NAUE(66.19%) and grain yield(11463.85 kg/hm2). Meanwhile, it could accelerate the N accumulation at main growth stages when the combined application rate was 180 kg/hm2 (slow-released urea and conventional urea were 126 kg/hm2 and 54 kg/hm2, respectively) and plant spacing was 16 cm, but it might cause the risk of N retention at grain filling stage which decrease the nitrogen translocation rate and finally reduce the nitrogen harvest index (NHI) and NAUE. It is better when the combined application rate was 150 kg/hm2 with slow-released N fertilizer was 96 kg/hm2 and conventional urea was 54 kg/hm2 in terms of high yield and high efficiency. However, when the plant spacing was increased to 20 cm, the absolute value of N absorption at main growth stage was decreased, the N translocation amount from stem sheath and leaves to panicle was increased as well as N accumulation amount of panicle. The grain yield and NAUE were increased with the rising slow-released urea application rate. In this conditions, the combined application rate was 180 kg/hm2 (slow-release urea and conventional urea were 126 kg/hm2 and 54 kg/hm2, respectively) was superior to any other treatments. Correlation analysis indicated that the highest correlation (r=0.54**~0.85**) between the total N accumulation amount, N translocation amount of leaves from full heading stage to maturity stage and grain yield and NAUE was obtained which might play an important role in improving NAUE and grain yield.【Conclusion】The plant spacing was 18 cm, the N for 150 kg/hm2 (slow-released urea and conventional urea were 96 kg/hm2 and 54 kg/hm2) could maximize N increment of panicle, NAUE and grain yield.

Select

Ammonia Volatilization Loss and Nitrogen Use Efficiency in Double-cropping Rice Field as Affected by Decreasing Controlled-release Urea Application Level Chang TIAN, Xuan ZHOU, Guixian XIE, Qiang LIU, Xiangmin RONG, Yuping ZHANG, Lizhang TAN, Jianwei PENG 2018, 32(4): 387-397.  DOI: 10.16819/j.1001-7216.2018.8004 Abstract ( )   HTML ( )   PDF (965KB) ( )   【Objective】The research aims to reveal the effects of controlled-release urea(CRU) application in successive years on double-cropping rice yield, nitrogen use efficiency (NUE), and ammonia (NH3) volatilization loss, and to lay a theoretical basis and develop a new method for reducing nitrogen losses in paddy field while stabilizing grain yield. 【Method】There were six treatments including zero-N (CK), urea (U) and four CRU levels (CRU1, CRU2, CRU3, CRU4, 0, 10%, 20% and 30% nitrogen reduction of CRU) in cultivars Zhongzao 39 for early rice and Taiyou 390 for late rice. Ammonia volatilization were measured by using continuous air flow enclosure method, as well as grain yield and N content.【Result】NH3 volatilization after basal fertilization and fertilizer application for tillering (U, CRU) peaked within 1-2 d, 2-4 d, lasting 8-9 days in early-rice season; peaked within 2-3 d and 3-4 d, lasting for 6-7 days for late-rice season. U application generated the highest total NH3 volatilization loss (rate) of 47.2 kg/hm2 (26.4%), and 61.9 kg/hm2 (28.7%), with grain yields of 5.5 t/hm2 and 6.2 t/hm2, and NUE of 23.0% and 20.0% for early- and late-rice season, respectively; Total NH3 volatilization loss (rate) of CRU treatments in early and late rice seasons were 22.8-32.3 kg/hm2 (14.6%-16.5%), and 30.4-42.1 kg/hm2 (15.9%-17.6%), with grain yields 5.8-6.3 t/hm2 and 6.6-7.5 t/hm2, and NUE 34.3%-40.5% and 33.8%-39.2% for early- and late-rice seasons, respectively; And CRU1 treatment reduced total NH3 volatilization loss by 40.9% and 38.3%, increased grain yield by 14.9% and 20.9%, NUE by 75.6% and 96.0% for early- and late-season rice than those of U treatment. Total NH3 volatilization loss and grain yield for early-, late-season and annual rice in CRU treatments had significant linear relationship with N application rate, namely increased with the rising N application rate. 【Conclusion】Application of CRU significantly reduced NH3 volatilization loss, and increased grain yield and NUE in double-cropping rice system, especially in CRU1 treatment.

Select

Effect of Temperature on Development and Parasitizing Capacity of Trichogramma japonicum Reared on the Eggs of Rice Moth (Corcyra cephalonica) Changchun RUAN, Ruotian GUO, Xiaoxuan HU, Wenmei DU, Liansheng ZANG, Junjie ZHANG 2018, 32(4): 398-404.  DOI: 10.16819/j.1001-7216.2018.7134 Abstract ( )   HTML ( )   PDF (917KB) ( )   【Objective】The research aims to reveal the effects of gradient constant temperature on development and parasiting ability of Trichogramma japonicum reared on the eggs of rice moth(Corcyra cephalonica) .【Methods】The life table of the experimental population of T. japonicum from Jilin Province at five different temperatures (15℃, 20℃, 25℃, 30℃ and 33℃) was constructed. The developmental threshold temperature and effective accumulative temperature for whole generation were calculated based on the developmental duration and rate. Then, the linear regression model was applied to simulate the growth rate. 【Results】With increasing temperature, the number of host eggs parasitized per females rose first and then fell. The largest number was 29.75 at 30℃, and there was no significant difference between 25℃ and 30℃. However, it was obviously higher than that of the other three temperatures. The females exhibited a significant decrease in longevity as the temperature increased. The maximum survival time of females was at 15℃, longer than other temperatures. When the temperature was over 30℃, the females survived for only 0.82 days. The highest emergence rate, came at 25℃, was 98.14%, while the lowest emergence rate was 67.96%. The developmental rate was remarkably linear correlative with temperature. The developmental threshold temperature and effective accumulative temperature of whole generation were 11.49℃ and 131.39℃ per day, respectively. 【Conclusion】The temperature was the most important factor for the population growth of T. japonicum. It was concluded that the best suitable temperature for industrialized reproduction ranged from 25℃ to 30℃.

Select

Influence of Image Features and Sample Sizes on Rice Pest Identification Pengpeng MA, Aiming ZHOU, Qing YAO, Baojun YANG, Jian TANG, Xiuqiang PAN 2018, 32(4): 405-414.  DOI: 10.16819/j.1001-7216.2018.7116 Abstract ( )   HTML ( )   PDF (1010KB) ( )   【Objective】In the traditional pattern recognition methods, image features and the sizes of training samples have a great influence on the identification results of target objects from a large number of distraction objects. Our objective is to study the influence of different image features and sample sizes on identification of rice light-trapped pests. 【Methods】 Rice light-trapped insects were divided into two broad categories：big insects and small insects. The global and local image features of all insects were extracted and different sizes of training samples were set to train support vector machine classifiers. 【Result】The support vector machine classifier based on the combination of global features and HOG features could obtain the identification rate of 91.4% and false detection rate of 8.6% when the non-target sample size was fourfold as many as target samples in big rice pests. The support vector machine classifier based on global features could obtain the identification rate of 94.9% and false detection rate of 4.9% when the non-target sample size was two times as many as target samples in small rice pests. 【Conclusion】In the small sample sets, appropriate image features and reasonable training sample proportion help achieve good identification results when some targets need to be identified from a large number of non-target objects.