The Microstructure,Antibacterial and Antitumor Activities of Chitosan Oligosaccharides and Derivatives     

Dawei Yu  Jiayao Feng  Huimin You  Shipeng Zhou  Yan Bai  Jincan He  Hua Cao  Qishi Che  Jiao Guo  Zhengquan Su 《Marine drugs》2022,20(1)

Chitosan obtained from abundant marine resources has been proven to have a variety of biological activities. However, due to its poor water solubility, chitosan application is limited, and the degradation products of chitosan oligosaccharides are better than chitosan regarding performance. Chitosan oligosaccharides have two kinds of active groups, amino and hydroxyl groups, which can form a variety of derivatives, and the properties of these derivatives can be further improved. In this review, the key structures of chitosan oligosaccharides and recent studies on chitosan oligosaccharide derivatives, including their synthesis methods, are described. Finally, the antimicrobial and antitumor applications of chitosan oligosaccharides and their derivatives are discussed.  相似文献   

生物入侵机理研究进展   总被引：4，自引：0，他引：4  

曹建华  蒋菊生  安峰 《华南热带农业大学学报》2006,12(3):52-58

综述生物入侵机理的生态学研究、生理学研究、分子生物学研究,并展望今后的研究方向。  相似文献   

江苏省2005年营造林实绩结果浅析     

曹国华  李思刚  张谷 《华东森林经理》2006,20(3):17-20

从工程类型、造林地类型、主要造林树种等方面对2005年全省人工造林实绩进行了分析,指出存在的主要问题,并提出摸清家底,合理下达造林计划;加强基层林业站建设,逐步完善营造林基础性工作;因此制宜,适度推广微型林网、宽窄行造林模式等三方面对策措施。  相似文献   

Physiological and anatomical changes in two rapeseed (Brassica napus L.) genotypes under drought stress conditions     

Jiacheng Zhu  Dongfang Cai  Jianping Wang  Jinhua Cao  Yancheng Wen  Junping He  Lei Zhao  Dongguo Wang  Shufen Zhang 《中国油料作物学报(英文)》2021,6(2):97-104

Understanding the mechanisms of drought resistance in crop species is crucial for the selection and breeding of tolerant rapeseed (Brassica napus L.) varieties. The present study aimed to assess the physiological and anatomical responses of two rapeseed genotypes, P287 (drought-tolerant) and T88 (drought-sensitive) under three intensities of drought stress. All physiological and anatomical parameters related to drought acclimation were significantly altered in both genotypes under stress conditions. At the fourth-leaf stage, the relative water content, chlorophyll content, protein content, malondialdehyde content, and the activities of peroxidase and catalase in P287 were significantly higher than those in T88, particularly under severe drought conditions. After rehydration, all physiological indexes recovered rapidly, especially in P287. In addition, under drought stress, compared with T88, P287 had thicker palisade tissue, thinner spongy tissue, higher ratio of chloroplast length to chloroplast width, higher stomatal density and stomatal closure rate. Overall, the interaction between physiological and anatomical features improved the drought tolerance of P287 under drought stress conditions.  相似文献   

论农业文化遗产保护与美丽乡村建设——以云南为例   总被引：1，自引：1，他引：0  

曹茂  莫力  杨玲 《农学学报》2020,10(8):89-94

党的十九大提出了乡村振兴战略,美丽乡村是农业文明的重要体现,是中华民族的文化根脉和精神家园。云南有着丰厚的农业文化遗产,本文从农业文化遗产地村落景观保护、特有农作物品种保护和加大农业文化遗产宣传保护等层面,提出了挖掘云南农业文化遗产及建设云南美丽乡村的对策建议。  相似文献   

旱碱地增施叶面肥对减氮棉田冠层光分布及产量的影响     

平文超  蒋建勋  刘贞贞  曹平平  王长安  王安录  赵光辉  张忠波 《中国棉花》2020,47(8):20-24

为了研究机采种植模式下不同水平减施氮肥后增施叶面肥对棉花花铃期冠层光分布、叶面积指数及与产量的影响,旱碱地条件下,设置0（CK）、60（N1）、90（N2）、120（N3）、150（N4）、180（N5,当地常规施氮量）、225 kg·hm^－2 （N6）7个施氮水平,其中N1～N4喷施叶面肥4次,测定花铃期群体叶面积指数（Leaf area index, LAI）、冠层光分布和籽棉产量。结果表明：与当地常规施氮量相比,减施（60～150 kg·hm^－2）氮肥后,棉花花铃期叶面积指数降低0.7%～5.5%,冠层光总截获率降低0.2～1.7百分点,冠层光透射率升高0.2～0.8百分点;各减施氮肥处理群体叶面积指数与冠层上层叶片的光截获率均呈显著正相关,与下层叶片的光截获率则呈负相关;籽棉产量随施氮量的减少而降低,二者有较高的相关性（R²＝0.990 5）。减氮（90～150 kg·hm^－2）增施叶面肥处理的LAI、冠层光总截获率、光透射率、冠层上下层叶片光截获率以及籽棉产量与当地常规施氮量180 kg·hm^－2处理差异均不显著。综上,旱碱地机采模式棉田增施叶面肥,对减施氮肥棉花花铃期冠层光分布、叶面积指数及籽棉产量有一定补偿作用。  相似文献   

Potential Anti-Aging Substances Derived from Seaweeds     

Lei Cao  Sang Gil Lee  Kwon Taek Lim  Hyeung-Rak Kim 《Marine drugs》2020,18(11)

Aging is a major risk factor for many chronic diseases, such as cancer, cardiovascular disease, and diabetes. The exact mechanisms underlying the aging process are not fully elucidated. However, a growing body of evidence suggests that several pathways, such as sirtuin, AMP-activated protein kinase, insulin-like growth factor, autophagy, and nuclear factor erythroid 2-related factor 2 play critical roles in regulating aging. Furthermore, genetic or dietary interventions of these pathways can extend lifespan by delaying the aging process. Seaweeds are a food source rich in many nutrients, including fibers, polyunsaturated fatty acids, vitamins, minerals, and other bioactive compounds. The health benefits of seaweeds include, but are not limited to, antioxidant, anti-inflammatory, and anti-obese activities. Interestingly, a body of studies shows that some seaweed-derived extracts or isolated compounds, can modulate these aging-regulating pathways or even extend lifespans of various animal models. However, few such studies have been conducted on higher animals or even humans. In this review, we focused on potential anti-aging bioactive substances in seaweeds that have been studied in cells and animals mainly based on their anti-aging cellular and molecular mechanisms.  相似文献   

Application method affects pesticide efficiency and effectiveness in wheat fields     

Jinjing Xiao  Li Chen  Fan Pan  Yajing Deng  Chenchun Ding  Min Liao  Xianyan Su  Haiqun Cao 《Pest management science》2020,76(4):1256-1264

  相似文献   

Paraphoma root rot of alfalfa (Medicago sativa) in Inner Mongolia,China     

S. Cao  Q. W. Liang  C. Nzabanita  Y. Z. Li 《Plant pathology》2020,69(2):231-239

Root rot symptoms were observed in fields of alfalfa in Chifeng city, Inner Mongolia, China in 2016. Disease incidences of seven alfalfa varieties planted in 2014 ranged from 56% to 95%, while incidence of Gongnong No. 1 planted in 2016 was 8%, 31% and 76% in 2016, 2017 and 2018, respectively. Paraphoma isolates were consistently recovered from black necrotic root tissues of diseased plants with a frequency of 77.1%. Based on morphological characters and phylogenetic analysis of rDNA internal transcribed spacer (ITS), elongation factor 1-α (EF1-α) and β-tubulin (TUB), this fungus was identified as Paraphoma radicina. Glasshouse pathogenicity experiments showed that P. radicina significantly reduced above- and below-ground biomass of alfalfa plants 2 months after inoculation. Paraphoma radicina infected 70% of the plants inoculated with a root dip in conidia, and these symptoms were consistent with the symptoms in the field. Paraphoma radicina was successfully reisolated from disease roots of the inoculated alfalfa plants. This is the first report of P. radicina as the causal agent of alfalfa root rot in China.  相似文献   

不同行距配比对玉米光合生理指标及茎秆特性的影响   总被引：2，自引：2，他引：0  

常海霞  郭红亮  刘永忠  李万星  曹晋军  靳鲲鹏  李丹 《中国农学通报》2020,36(17):16-20

以‘大丰30’为试验材料,在同一密度下（75000株/hm²）设置5种不同行距配比,研究不同行距配比对玉米光合生理指标及茎秆力学特性的影响。结果表明：行距配比为40 cm×80 cm时,棒三叶的叶绿素含量(SPAD)在灌浆期达到峰值;行距配比为30 cm×90 cm时,棒三叶净光合速率在灌浆期最高。大口期开始,行距配比为40 cm×80 cm时,叶面积指数(LAI)最高。单株干物质积累量以40 cm×80 cm最高。各行距配比的茎秆硬皮穿刺强度与茎秆弯曲性能随着节位的下降均呈逐渐增强的趋势,从大到小为 40 cm×80 cm>50 cm×70 cm>30 cm×90 cm>60 cm×60 cm>20 cm×100 cm。穗长、穗粗、千粒重和穗粒数各处理间均有不同变化,行距配比为40 cm×80 cm时产量最高,比等行距60 cm×60 cm增产7.96%。由此可见,行距配比为40 cm×80 cm,有利于大穗型品种‘大丰30’的光合性能和茎秆强度的提高,从而达到抗倒伏增产的目的。  相似文献