Improving maize grain yield by formulating plant growth regulator strategies in North China

Plant growth regulators(PGRs) are artificially synthesized compounds that have become an important technical guarantee for agricultural production. EDAH(containing 27% ethephon and 3% DA-6) has been proven to inhibit stalk elongation, promote stalk bold and increase mechanical strength and number of vascular bundles. DA-6 could enhance plant photosynthetic capacity and promote cell division and growth. In our study, experiments were performed at summer maize growing season during 2018–2019. The result showed that plant height, ear height and center of gravity height of maize with EDAH+DA-6 treatment were decreased by 10.18, 16.77 and 13.21%, respectively; leaf area and leaf area index also significantly(P0.001) decreased by 24.11 and 60.15%, respectively; the value of mean tilt angle significantly(P0.001) increased by 16.72% compared with the control plants, which meant that EDAH+DA-6 could shape more compact plant type. Therefore, lodging rate of maize with EDAH+DA-6 treatment decreased by 6.95% compared with control plants, and the grain yield was increased by 15.51%. In addition, EDAH+DA-6 treatment significantly improved the quality of maize base stalks, such as improving mechanical properties, which increased maize base stalk crushing strength by 22.23%; increased the hemicellulose, cellulose and lignin contents by 6.93, 3.87 and 30.21%, respectively. In conclusion, EDAH+DA-6 treatment could improve summer maize yield by shaping plant morphological characteristics and group photosynthesis.     

Production and application of on‐grown Artemia in freshwater ornamental fish farm

Abstract

This paper describes a pilot culture system for the production of on‐grown Artemia in freshwater ornamental fish farms. The system had 21 culture units, each consisting essentially of three components: an oval‐shaped raceway, an air‐water lift system and two waste collectors. Using artificial seawater at 20 ppt for culture and at a mean production rate of 3 kg/m³ of water in a 12‐day cycle, the system had a production capacity of 8 metric tons of on‐grown Artemia a year. Biochemical analyses were preformed to evaluate the nutritional value of the on‐grown Artemia against three conventional live feeds, viz. live Artemia nauplii, live Moina and frozen bloodworms. Cost‐benefit analysis showed that with a capital investment of US$ 82,000 and an annual cost of production of US$ 81,000, the system achieved a high internal rate of return of 88% over a 10‐year period and a short payback period of 1.23 years. The availability of on‐grown Artemia would not only offer farmers and exporters a better alternative live food organism for feeding to their fish, but more importantly the possibility of enhancing the fish performance and quality through bioencapsulation.     

木材超高温热处理技术的研究及应用进展

从研究背景、生产工艺及应用前景等方面,介绍木材超高温热处理技术在国外的发展、应用及研究状况.资料表明,木材经热处理改性后,尺寸稳定性增强、平衡含水率降低,且耐候性及抗生物降解能力增强.此技术的研究及应用,对扩大人工林木材的加工利用可起到积极的促进作用.     

Change in nutrient composition of Artemia grown for 3–4 days and effects of feeding on‐grown Artemia on performance of Atlantic halibut (Hippoglossus hippoglossus,L.) larvae

Major challenges in culture of Atlantic halibut larvae have been slow growth during the late larval stages and inferior juvenile quality due to pigmentation errors and incomplete eye migration during metamorphosis. The hypothesis of this study was that feeding on‐grown Artemia would alleviate these problems. Artemia were grown for 3–4 days on Origreen or Origo. The growth and nutrient composition of Artemia nauplii and on‐grown Artemia were analysed, and both Artemia types were fed to Atlantic halibut larvae, on‐grown Artemia from 15 days post‐first feeding (dpff). The body length of Artemia increased with 20%–70% in response to on‐growing. In all experiments, protein, free amino acids and the ratio of phospholipid to total lipid increased, while lipid and glycogen decreased. The fatty acid composition improved in some cases and not in others. The micronutrient profiles were not negatively affected in on‐grown Artemia. All these changes are thought to be beneficial for marine fish larvae. The final weight of Atlantic halibut postlarvae was similar, and 90% of the juveniles had complete eye migration in both groups. It is concluded that the present version of Artemia nauplii probably covers the nutrient requirements of Atlantic halibut larvae.     

油茶高产栽培系列技术研究——配方施肥试验

以油茶优良无性系成林和幼林为材料,通过随机区组和正交试验,结果表明配方施肥对油茶优良无性系成林和幼林产果量增加均有不同程度的促进作用.油茶成林对产果量最大的影响因子是施肥总量,其次是微量元素肥、施肥频率和施肥配比;较合理的施肥配比组合应为:施肥总量(200 kg·hm-2) 微量元素肥(Zn 10 g·株-1) 施肥频率(连续3年施肥) 施肥配比(5∶1∶5),增产幅度可达58.69%.油茶成林鲜果出籽率最大影响因子是微量元素肥、其次是施肥总量,施肥配比和施肥频率;而每500 g鲜果数最大影响因子是施肥配比、其次是微量元素肥、施肥频率和施肥总量等因子;油茶优良无性系新造幼林施肥也能明显提高油茶单株产果量,其中以间年施肥、每年施肥量为N∶P2O5∶K2O为2∶1∶2;平均单株产果量达1.16 kg,比对照增产136.4%.增施磷肥能明显促进油茶幼林早期挂果.配方施肥对油茶幼林鲜果出籽率没有明显的影响.     

壮蚕感染微孢子虫与蛾期毒率的关系

采用口腔微量注射接种法,研究了壮蚕(4～5龄)感染微孢子虫与蛾期微粒子病显微镜判别的关系.结果表明:在一定范围内,显微镜检别出微粒子病的时期随微孢子虫接种剂量的增大而提早,造成蚕蛾镜检有毒的壮蚕感染微孢子虫的下限剂量为32～64个/条,其下限感染剂量在不同发育阶段的蚕之间存在一定差异.本试验结果对于当前蚕种生产上微粒子病的防治工作有积极指导意义.     

速生杨木染色效果的色差分析

木材染色是人工林速生材常用的一种改性处理方法.以染液温度、染色时间和染液浓度作为变化因素,对速生杨木染色效果进行色差检验,分析了染液温度、染色时间和染液浓度对速生杨木染色后色差变化趋势的影响.     

温室容器育苗基质及苗木生长规律的研究

通过对不同育苗基质上生长的香椿、日本落叶松、侧柏、油松等４ 个育苗树种的苗高、地径、地上部分干质量、地下部分干质量、总干质量和地上—地下干质量比等项目进行定期生长监测和统计分析，初步筛选出适宜当地的较为经济的育苗基质；并得出该４个树种容器苗的苗期生长变化规律。     

8种原生蔬菜氨基酸组成及营养评价

对8种原生蔬菜氨基酸含量及组成进行分析测定,并采用模糊识别法和氨基酸比值系数分法对其蛋白质营养价值进行评价。结果表明,8种原生蔬菜氨基酸含量丰富,种类齐全,必需氨基酸含量较高,占总氨基酸含量的38.36%~44.08%;鲜味氨基酸占总氨基酸含量的21.46%~26.59%。模糊识别法评价蛋白质营养价值高低为：苦菜〉羽衣甘蓝〉九层塔〉紫背天葵〉番杏〉猫薄荷〉芹菜〉马齿苋〉马兰〉空心菜〉卷心菜〉生菜;用氨基酸比值系数分法评价,蛋白质营养价值高低为：番杏〉芹菜〉苦菜〉马兰〉九层塔〉紫背天葵〉羽衣甘蓝〉猫薄荷〉卷心菜〉生菜〉马齿苋〉空心菜。2种评价方法的评价结果不尽一致,但是总体上可以得出,原生蔬菜氨基酸组成平衡且优质,其蛋白质营养价值高于 所选的普通蔬菜对照品种,具有较高的开发利用价值。     

利用扫描电镜原位拉伸研究竹材增韧机制

为了阐明竹材优良韧性的力学原理,以毛竹为研究对象,使用扫描电镜联用原位加载设备观察了竹材薄片纵向拉伸过程的裂纹扩展规律,并对断裂表面进行了组织水平、细胞水平、亚细胞水平的多尺度显微观察。结果表明:竹材纵向拉伸断裂裂纹拓展一般呈阶梯型展开。维管束与基本组织之间、竹纤维与薄壁组织细胞之间、纤维和薄壁细胞的壁层之间均有明显的分层现象,表明竹材断裂过程中存在从组织到细胞,乃至亚细胞水平的多级弱界面。这些弱界面可以有效阻碍裂纹扩展,增加断裂消耗功,从而显著增强竹材的韧性。