基于STM32温室环境测控系统的研究

在传统温室自动化监控系统的基础上,针对目前温室大棚面积不断增大、温室内传感器种类及数量不断增多,且不易连栋管理的现状,设计了基于ARM CORTEX-M3核的以STM32单片机为核心的智能温室控制系统。系统采用CAN总线技术对连栋大棚的主要环境因子,如温度、湿度及光照度等进行智能控制,通过串行通信实现上位机控制,增强了温室大棚的智能化和实用性。     

混氢改善汽油机低怠速性能研究

在一台加装了电控氢气喷射系统的四缸汽油机上,试验研究了混氢对发动机低怠速性能的影响。在怠速转速不变、维持进气混合气处于当量比的条件下,在0～6%的范围内逐渐增加氢气在总进气中的体积分数,测试了发动机转速分别为800、700、600 r/min时的低怠速性能。试验结果表明,纯汽油机怠速为800 r/min时,发动机稳定运行的燃料能量流量Ef为30.8 MJ/h,而当混氢分数增加至6.0%、怠速转速降至600 r/min时,Ef降低至18.6 MJ/h;随进气混氢体积分数的提高,发动机低怠速时的燃烧持续期缩短,HC、CO及NOx排放量降低,循环变动也减小。可见,进气掺氢可有效改善发动机的低怠速性能。     

白芝麻油脂理化特性及组成分析

分析测定了不同产地白芝麻压榨油脂的折光指数、皂化值及不皂化物含量等理化指标;采用气相色谱法分析了压榨白芝麻油中脂肪酸成分含量,其不饱和脂肪酸的相对含量占84％以上;并用胰脂酶选择性水解方法分析了压榨白芝麻油的甘三酯分子结构组成,发现其LOL相对含量最高(22.98％ ～25.62％);高效液相色谱法测定压榨芝麻油中维生素E含量为13.73 ～ 54.43 mg/(100 g),芝麻素含量为60.14 ～69.10 mg/(100 g);分析测定了不同产地芝麻制取的压榨白芝麻油氧化稳定性,结果表明,白芝麻油4号氧化稳定性相对较好.     

基于物元分析法的土地健康评价——以湖北省枣阳市为例

针对综合指数评价法存在的信息遗漏及主观等问题,该文采用物元分析法对湖北省枣阳市土地健康水平进行评价。在诠释土地生态安全概念的基础上,基于“生态—经济—社会”模式和层次分析法构建土地健康评价的指标体系,运用物元分析方法构建土地健康评价的综合评判模型,并以湖北省枣阳市为例进行了实证研究。研究结果表明:吴店镇和七方镇土地处于健康状态,新市镇和太平镇土地处于不健康状态,其他8乡镇土地处于亚健康状态。根据评价结果,该文提出相关政策建议,从而为枣阳市土地的健康、可持续利用提供指导。      

Stable C and N isotope values of selected components of a tropical australian sugarcane ecosystem

The ¹³C and ¹⁵N values of sugarcane plant tissues, decomposing harvest residues, soil and the casts and body tissues of the earthwormPontoscolex corethrurus were determined. Little variation in ¹³C values was found between plant parts. The ¹³C values of the decomposing harvest residues declined and became more variable after 148 days of exposure in the field. In the decomposing residues, ¹³C values of the neutral detergent fibre fraction were similar to those of the whole tissues while those of the proximate lignin were more negative. The ¹⁵N values of the residues also declined over time after a short initial delay.P. corethrurus populations are more intimately associated with the roots of sugarcane than with the bulk soil. Tissue ¹³C values suggest that the earthworm diet is similar to or more enriched in¹³C than sugarcane tissues and is substantially more enriched than the soil C. Earthworm tissues have similar levels of¹⁵N enrichment to both the soil and plant tissues. These data are consistent with the hypothesis that this earthworm derives much of its assimilated C relatively directly from organic matter associated with the roots and decomposing harvest residues.     

杉木林下套种不同树种对土壤改良效应初探

为探讨复层异龄林营建初期对土壤物理结构和养分状况的影响,研究了浙西地区杉木林下套种不同树种土壤理化特征的变化。结果表明林下套种树种后林地土壤物理结构均得到不同程度的改善,土壤养分状况进一步好转。并运用多因素主成分分析方法,评价了不同复层林模式土壤养分含量规律,并将土壤养分状况的综合优势作了排序。其结果显示杉木林下套植的12种植物在种植初期对土壤养分改良效果较好的为麻栎、毛红椿、南天竺、十大功劳、红豆杉、椤木石楠和蚊母,其中麻栎和毛红椿改良效果最佳。     

Differential and successive effects of residue quality and soil mineral N on water-stable aggregation during crop residue decomposition

Residue quality has been shown to influence soil water-stable aggregation (WSA) during crop residue decomposition, but there is still little information about its interactive effect with soil mineral N availability. The aim of this study was to determine the effect of soil mineral N on WSA during the decomposition of two high-C/N crop residues (wheat straw with C/N = 125.6 and miscanthus straw with C/N = 311.3). The two crop residues were combined with three mineral N addition rates (0, 60, and 120 mg N kg⁻¹ dry soil). Respiration, soil mineral N content, and WSA (expressed as mean-weight diameter, MWD) were measured on several dates during a 56-d incubation. The effect of decomposing crop residues on WSA followed two phases. (i) Between 0 and 7 d, the increase in WSA was related to intrinsic residue quality with higher decomposability of the wheat straw resulting in higher WSA. (ii) Thereafter, and until the end of the experiment, mineral N addition rates had a predominant but negative influence on WSA. In this second phase, the average MWD of residue-treated soils was 0.92, 0.55, and 0.44 mm for the 0, 60 and 120 mg N kg⁻¹ dry soil addition rates, respectively. Mineral N addition which did result in higher crop residue decomposition did not lead to higher WSA. WSA during crop residue decomposition is therefore not simply positively related to the induced microbial activity, and changes in microbial community composition with differential effects on WSA must be involved. The impact of high-C/N crop residues inputs on WSA, initially assumed to be low, could actually be strong and long-lasting in situations with low soil mineral N content.     

基于GIS和NFM的鄱阳湖地区经济林地的适宜性评价

土地资源是制约经济增长和改善人民生活最严重的"瓶颈",为了让有限的土地资源得到充分、合理的利用,系统开展区域土地资源空间优化配置的研究是一项十分迫切的任务,而进行经济林用地适宜性评价是土地资源优化配置的重要内容,对制定土地利用规划、进行林业结构调整、保护区域生态环境、实现区域资源环境可持续发展具有重要意义。     

Agrobacterium-mediated transformation of the CrDAT gene and selection of transgenic periwinkle lines with a high vincristine accumulation

Catharanthus roseus contains vincristine and vinblastine, which are outstanding drugs for cancer. In the biosynthetic pathways of terpenoid indole alkaloids (TIAs) in C. roseus, deacetylvindoline 4-O-acetyltransferase (DAT) is a key enzyme that catalyses the last reaction of vindoline biosynthesis to form vinblastine and vincristine. In this study, the CrDAT transgene was transferred into the periwinkle by Agrobacterium-mediated transformation and generated transgenic periwinkle lines with an increase in vincristine accumulation. The C. roseus DAT gene was introduced into C. roseus plants and it was confirmed that CrDAT was successfully transferred into the genome of periwinkle plants and efficiently translated to synthesise recombinant DAT protein. Four transgenic periwinkle lines in T1 generation, T1-1, T1-3, T1-6, and T1-7, expressed recombinant DAT protein with the total protein content in the range of 2.86 μg.mg^?1 to 5.12 μg.mg^?1. Moreover, the vincristine contents of four transgenic lines increased by 1.63?2.48-fold compared to non-transgenic plants, ranging from 6.91 µg.g^?1 (fresh weight) to 10.53 µg.g^?1 (fresh weight). The T1-1 line had the highest vincristine content. Hence, the overexpression of the recombinant DAT protein can improve the vincristine accumulation of transgenic C. roseus plants.

Abbreviation: CrDAT - Catharanthus roseus Deacetylvindoline-4-O-Acetyl Transferase; D4H - Deacetoxyvindoline 4-hydroxylase; ELISA - Enzyme-Linked Immunosorbent Assay Monoterpene indole alkaloid; T0, T1 - Generations of transgenic plants; TIAs - Terpenoid indole alkaloids; WT- The wild-type tobacco plants (non transgenic plant); 35S - Cauliflower mosaic virus 35S promoter     

Flavan-3-ols and procyanidins in grape seeds: biodiversity and relationships among wild and cultivated vines

Flavan-3-ol monomers and polymers composition of seeds from wild (17) and autochthonous (8) Vitis vinifera grapes growing in northern Tunisia were evaluated. Wild grape seeds were spherical with a small beak and relatively a high seed/berry ratio (~ 18.1%w/w). Local cultivars developed pyriform-shaped seeds with a well-developed beak representing on average 2.2% of total weight of the berry. Flavanol concentrations ranged between 40.9 and 67.5 mg/g FW in seeds from wild accessions and between 48.9 and 96.7 mg/g FW in seeds from cultivated grapes. Differences between accessions were highly significant (p < 0.01) and seeds from cultivar ‘Boukhasla’ showed the highest polyphenols content. Among flavan-3-ol monomers, (+)-catechin was predominant for all ecotypes and generally their abundance was: (+)-catechin (Cat) > (?)-epicatechin (Ec) > (?)-epicatechin-3-O-gallate (EcG). The Cat/Ec ratio was approximately 1.7 for wild grapes while it was about 2.5 for cultivated grapes. Procyanidins in wild seeds differed from cultivated ones by a lower mDP and higher proportions of galloylated derivatives, likely to affect fruit bitterness and astringency. (?)-epicatechin was the main extension subunit in grape seed procyanidins, reaching on average 52% in wild and 58% in cultivated seeds. Hierarchical cluster analysis based on seeds morphometry and procyanidin profile indicated close proximity between some wild and cultivated grapes suggesting that some cultivars derived from ancestral events of local domestication or cross hybridization with native wild plants.