Automated measurement of canopy stomatal conductance based on infrared temperature

Decreased water uptake closes stomates, which reduces transpiration and increases leaf temperature. The leaf or canopy temperature has long been used to make an empirical estimate of plant water stress. However, with a few supplemental measurements and application of biophysical principles, infrared measurement of canopy temperature can be used to calculate canopy stomatal conductance (g_C), a physiological variable derived from the energy balance for a plant canopy. Calculation of g_C requires an accurate measurement of canopy temperature and an estimate of plant height, but all of the other measurements are available on automated weather stations. Canopy stomatal conductance provides a field-scale measurement of daily and seasonal stomatal response to prevailing soil water and atmospheric conditions, and facilitates a comparison of models that scale conductance from single leaves (measured with porometers) to canopies. A sensitivity analysis of the input measurements/estimates showed g_C is highly sensitive to small changes in canopy and air temperature, and less sensitive to the other required measurements (relative humidity, net radiation, wind speed, and plant canopy height). The measurement of g_C becomes increasingly sensitive to all of the component factors as the conditions become cloudier, cooler, and more humid. We determined g_C for alfalfa and turfgrass by making the necessary environmental measurements and coupling them with a two-source (plant canopy layer and soil layer) energy balance model. We then compared these g_C values to maximum single leaf values scaled-up to the canopy level (g_CP, defined as potential canopy stomatal conductance herein) for the two crops. For both crops, g_C matched g_CP within approximately 10% after irrigation. The turfgrass g_C measurements were also compared to mean single leaf values measured with a porometer. At mid-day, g_C values were typically about double the single leaf values. Because this approach for determining g_C allows continuous, non-contact measurement, it has considerable potential for coupling with measurements of soil moisture to better understand plant–soil water relations. It also has potential for use in precision drought stress and irrigation scheduling.     

EuFPS基因表达载体构建及对杜仲遗传转化的研究

本实验用EcoRⅠ和BamHⅠ双酶切植物表达载体pSH737和含有目的基因的pUC-FPS,定向连接得到重组质粒pSH-FPS,将其导入农杆菌EHA105。采用农杆菌介导法对杜仲进行遗传转化,研究了卡那霉素(kanamycin,Km)浓度、预培养时间、菌液浓度及侵染时间、乙酰丁香酮(acetosyringone,AS)浓度、共培养时间等对杜仲遗传转化效率的影响。结果表明,选择无菌苗苗龄15d的杜仲下胚轴,卡那霉素浓度50mg/L,农杆菌浓度OD600值0.3~0.6,侵染时间8min,侵染时菌体重悬液中添加50μmol/L乙酰丁香酮,共培养时间3d,抗性芽的获得率最高。对再生植株进行GUS检测发现有45%的植株呈阳性。     

链霉菌3-10发酵液及提取物的稳定性研究

为合理利用链霉菌3-10的代谢产物,本研究采用不同极性的有机溶剂提取链霉菌3-10发酵液中的抗真菌物质并得到发酵液的提取物.在此基础上测定了温度、紫外线辐射、酸碱度和贮存条件对3-10抗真菌物质稳定性的影响.结果表明,乙酸乙酯为最佳提取溶剂,链霉菌3-10发酵液的乙酸乙酯提取物对灰霉病菌菌丝生长的抑制作用最强,提取后余...     

植物细胞全能性理论在中国的研究与实践

自1902年德国科学家Haberlandt提出“植物细胞全能性”的概念以来,无数中国学者对这一理论进行了大量的实验,从不同方面和层次对其进行验证和探索,取得了诸多有实践和理论意义的成果,丰富和充实了植物细胞全能性的理论。同时,基于该理论而发展起来的植物细胞离体培养技术在各方面也取得了可喜的成就。本文就植物细胞全能性基础理论方面的研究以及在生产实践中的应用作了比较系统的总结。     

植物非组培遗传转化方法研究的进展

在许多植物中,转化效率低一直是制约分子育种和基因功能研究的障碍。目前,在拟南芥等模式植物的研究中,非组培方法已成为遗传转化的主要手段,这些方法在其它植物中也有广阔的应用前景。本文介绍了几种较为成功的非组培遗传转化方法的应用情况和技术原理,并对下一步研究工作提出了建议。     

牛血清白蛋白泡沫法提取庆大霉素产物快速检测方法的研究

采用醋酸纤维薄膜电泳法分离庆大霉素与牛血清白蛋白,再用紫外分光光度法测定蛋白质泡沫法提取庆大霉素含量的方法.该方法中,选择620 nm作定量峰,庆大霉素和氨基黑10B的结合物浓度在1.25～10μg/mL范围内,吸收度与浓度的线性关系良好,相关系数为0.999 6,回收率为100.59%.     

樟科、丝兰属植物提取物对仔猪排泄物中氨和硫化氢散发的影响

研究旨在观察比较樟科植物提取物(CFPE)和丝兰植物提取物(YE)对仔猪生长性能、粪尿中氨和硫化氢散发的影响及其机理探讨。选用216头35日龄的杜长大仔猪,按照体重相近、公、母各半的原则分为3组,每组3个重复,每个重复24头仔猪。CFPE试验组和YE试验组分别饲喂含350 mg/kg CFPE和125 mg/kg YE的基础日粮,对照组饲喂基础日粮,试验期为35 d。结果表明:CFPE和YE均显著影响仔猪平均日增重(ADG)和饲料增重比(F/G()P<0.05),CFPE组ADG高于YE组,F/G低于YE组,但差异均不显著(P>0.05)。CFPE和YE对脲酶活性影响极显著(P<0.01),CFPE组脲酶活性低于YE组,但差异不显著(P>0.05);在粪尿排出后6 h时间点,CFPE和YE对尿素氮浓度有显著影响(P<0.05),从12 h时间点开始,影响达到极显著(P<0.01)。CFPE使氨态氮最高浓度出现时间点推迟,7 d时间点,CFPE、YE组的氨态氮浓度均极显著高于对照组(P<0.01),CFPE组高于YE组,但差异不显著(P>0.05)。除12 h和48 h时间点外,CFPE组、YE组的可溶性硫化物的浓度显著低于对照组(P<0.05),仔猪粪便发酵第4天和第8天产生的硫化氢平均值均极显著低于对照组(P<0.01)。结果提示,饲料中添加CFPE和YE可通过减缓尿素氮分解和可溶性硫化物的产生,从而减少氨和硫化氢的散发;CFPE效果优于YE。     

玉米、豆粕和麦麸抽提物对4株猪源乳酸杆菌耐酸能力的影响

采用模拟胃酸环境,检测饲料原料玉米、豆粕和麦麸抽提物对4株猪源乳酸杆菌耐酸性能的影响。结果表明:在pH 2.5模拟胃酸环境中处理3 h,约氏乳酸杆菌JJB3、SNZ10,罗伊氏乳酸杆菌MNZ8、KNZ4分别经90、30、60 min和30 min完全失活。添加豆粕和麦麸抽提物后,4株乳酸杆菌在pH 2.5模拟胃酸环境中处理3 h后活菌数没有显著变化。玉米抽提物只对JJB3具有很好的保护作用,可以延长SNZ10和KNZ4在酸性环境中的存活时间30 min,对MNZ8 30 min的成活率有一定的提高作用,但是不能延长它的存活时间。进一步的单因子分析表明,葡萄糖浓度变化显著影响乳酸杆菌的耐酸性,游离氨基氮含量对乳酸杆菌成活率几乎无影响。证明饲料原料豆粕和麦麸抽提物作为载体对4株乳酸杆菌耐酸性具有很好的保护作用,可作为提高乳酸杆菌制剂成活率的过瘤胃保护剂。     

甘肃马先蒿地上部分水浸液对不同牧草发芽和幼苗生长的影响

以垂穗披碱草、中华羊茅、短芒老芒麦、青牧1号老芒麦为供试材料,研究了不同浓度的甘肃马先蒿地上部分水浸液对四种牧草种子发芽和幼苗生长的影响。结果表明：不同浓度的甘肃马先蒿地上部分水浸液对供试牧草种子的萌发、幼苗生长和根长均有显著的抑制作用（P〈0．05）;对供试牧草种子萌发、幼苗生长和根长的抑制作用随着水浸液浓度的增加而加强。抑制作用总体上表现为中华羊茅〉垂穗披碱草〉青牧1号老芒麦〉短芒老芒麦。     

Dietary supplementation with Acanthopanax senticosus extract enhances gut health in weanling piglets

The present study was conducted to investigate the effects of Acanthopanax senticosus extract (ASE) as a dietary additive on gut health in weanling piglets by examining diarrhea frequency, intestinal microbiota and morphology. A total of 96 Duroc× (Landrace × Yorkshire) piglets weaned at 21 days of age with an average initial body weight (BW) of 5.6 ± 0.4 kg were randomly assigned to 3 treatment groups with 4 duplicates of 8 piglets each. The piglets were fed basal diet to which had been added 0 or 1 g/kg of ASE, or 0.7 g/kg antibiotics, respectively. Fecal consistence was monitored twice daily and the frequency of diarrhea was calculated. On day 21 after the initiation of supplementation, 8 piglets were randomly selected from each treatment group (2 piglets per pen) and slaughtered. The jejunum, ileum, colon and cecum were then excised and fixed in 10% neutral formalin solution to determine villus height and crypt depth, after their contents were collected to determine microbiota. The results showed that dietary supplementation with ASE increased (P < 0.05) the density of bacterial populations that co-migrated with Lactobacillus amylovorus, Lactobacillus salivarius, Bacillus subtilis, and Clostridium lituseburens, but decreased (P < 0.05) those co-migrating with Staphylococcus aureus, Salmonella typhimurium, Ruminococcus forques, and E. coli O157:H7 in the PCR-DGGE profiling analysis when compared with the control group. The villus height of the duodenum, jejunum and ileum increased (P < 0.05) by 14.8, 13.7 and 10.0%, while the crypt depth decreased (P < 0.05) by 17.9, 9.1 and 12.1%, respectively, in response to dietary ASE supplementation. Additionally dietary supplementation with ASE or an antibiotic decreased (P < 0.05) the frequency of diarrhea by 55.6 and 52.2%, respectively, compared with the control group. In conclusion, these findings suggest that dietary supplementation with ASE could regulate the microbiota composition and maintain a normal morphology of gut mucosa in weanling piglets, thereby decreasing diarrhea that resulted from weaning stress.