半干旱草原主要植物光能和水分利用特征的研究

在植物生长季内测定了内蒙古半干旱草原6种主要植物的光合和水分利用特征，比较了植物之间在光能和水分利用方面的差异，认为水分利用效率难以反应植物对干旱的适应性，而其倒数－水分竞争系数是较好的表征指标；植物的光能利用效率和水分竞争系数之间存在补偿关系；半干旱草原主要植物适应环境的方式不同，它们在光能和水分资源生态位上存在分离。     

非协调耦合视角下长江经济带高质量发展与生态保护的时空特征

[目的]科学测度长江经济带高质量发展和生态保护的非协调耦合度,为推动长江经济带高质量发展与生态保护提供科学依据.[方法]通过构建高质量发展与生态保护综合评价指标体系,以长江经济带108个城市为研究对象,采用非协调耦合、空间自相关等方法,探究了 2005-2018年长江经济带高质量发展与生态保护的非协调耦合关系.[结果]...     

陆上输油管道溢油扩散规律及泄漏后果研究进展

输油管道一旦泄漏不但会造成直接经济损失,而且将对周围环境、沿线居民带来不利影响,掌握泄漏油品在周围环境中的渗流、地表扩散以及蒸发情况,对于开展管道应急处理和泄漏后果评价至关重要。结合陆上输油管道泄漏事故特点,从事故条件下的泄漏量、泄漏油品的流动扩散规律以及泄漏后果等方面入手,对成品油管道泄漏油品研究成果进行了归纳总结,同时为进一步研究泄漏油品在周围环境的扩散过程,预估泄漏后果并制定合理的应急处理方案提出了建议。     

苹果褪绿叶斑病毒的ELISA检测技术研究

比较了直接双抗体夹心法 ( DAS- ELISA)和间接双抗体夹心法 ( F( ab) 2 -ELISA)检测 CLSV的范围 (不同株系 ) ,并分析了在病毒提取介质中加入某些特殊成分后 ,对直接双抗体夹心法检测 CLSV效果的影响。结果表明 ,间接法可以检测较宽范围的病毒株系 ;当常规病毒提取介质中加入尼古丁、氯化镁和聚酰胺时 ,标准双抗体夹心法的检测范围也可以扩大     

不同黑胫病发病程度下植烟根际土壤酶活性及细菌群落结构差异比较

土传病害的发生与土壤环境,特别是微生物群落结构变化密切相关,田间自然发病条件下探讨土传病害发生、发展过程中土壤环境因子的变化特征,可更加科学地评价病害发生与土壤环境因子变化的关系,为进一步了解土传病害发生机理提供必要科学依据。选择云南烟草黑胫病危害较为严重的3个植烟区(石林板桥、保山耇街、保山珠街)统一种植高感黑胫病烤烟品种红花大金元,调查定点田块病害发生情况并根据病害调查标准将发病烟株划分不同程度(正常烟株、轻度发病烟株、中度发病烟株、重度发病烟株)。同时在保山耇街试验点采集不同发病程度烟株根际土壤,分析比较其土壤酶活性及细菌群落的差异。研究结果表明:各调查点不同发病程度烟株根际土壤与脲酶、蔗糖酶、酸性磷酸酶、过氧化氢酶活性随发病程度增加均呈下降趋势;土壤16S rRNA高通量测序及多样性分析表明,与土壤细菌门类水平优势群落组成相似,并且随发病程度放线菌门相对丰度呈下降趋势,而酸杆菌门呈上升趋势;不同发病程度根际土壤细菌群落属水平上相对丰度差异较大,其中甾体杆菌属(Steroidobacter)、阿达尔杆菌属(Adhaeribacter)、根瘤菌属(Mesorhizobium)、杜氏杆菌属(Tumebacillus)随发病程度呈先下降后上升的趋势;细菌群落α多样性指数均不同程度低于健康根际土壤,且均表现为轻度发病烟株根际土壤α多样性指数最低,其中shannon和simpson指数轻度发病烟株显著低于健康烟株;PCoA主成分分析表明,根际土壤细菌群落结构随发病程度发生了明显分离,且沿第二主成分坐标轴上细菌群落结构分离随发病程度呈逐渐增大趋势。综上所述,不同发病程度烟株根际主要环境因子存在较大差异,土壤酶活性受到不同程度抑制,细菌群落组成发生趋向性变化,群落结构发生趋向性改变,土壤微生物多样性降低。     

花生在饲草生产中的间作套种技术与效果研究

本文研究了紫花苜蓿、白三叶、多年生黑麦草、鸡脚草和苇状羊茅等五种多年生牧 草与花生在“5+6”模式套作情况下生长特点以及对饲草生产的影响。花生与禾草的套作能够 极显著地促进禾草的分蘖(11．01％-14．26％)(P<0．01),显著增加其叶面积指数(4．62％- 6．37％),(P<0．05)三种禾草的产草量分别提高了8．2％、8．1％、9．3％。花生秧与禾草混合 调制后,饲草中的粗蛋白、粗脂肪和钙的含量得到了显著和极显著的提高,而粗纤维含量却明 显降低。紫花苜蓿和花生套作能够提高牧草产草量5．8％,豆科牧草与花生秧混合调制以后, 粗蛋白、粗纤维以及钙和磷的含量明显下降,粗脂肪得到了极显著的提高。     

灌水量对不同类型晚稻生育及产量影响的初步研究

采取盆栽遮雨人工定量灌水的方法,探讨了常规晚稻和杂交晚稻前后两大生育时期不同灌水量对生育和产量的影响.结果表明:两类型晚稻品种前后两个生育时期节水灌溉都能达到高产之目的,但不同类型和不同生育时期的最佳灌水量和节水效果不同.     

Effects of day and night temperature on photosynthesis,antioxidant enzyme activities,and endogenous hormones in tomato leaves during the flowering stage

To study the effects of day and night temperature difference (DIF) on tomato growth, a controlled experiment using Solanum lycopersicum L., cv. Jinguan 5 was conducted. The daily mean temperature (T_m) was maintained at 18°C and 25°C, and the DIF was set at 0°C, 6°C, and 12°C. The results indicated that chlorophyll a (Chl a) and chlorophyll b (Chl b) gradually increased as DIF rose. At 18°C T_m, the carotenoid content reached a maximum at 12°C DIF. The Chl a/Chl b, net photosynthetic rate (P_N), photosynthetic rate at irradiation saturation (P_max), stomatal conductance (g_s), intercellular CO₂ concentration (C_i), stomatal limitation value, the maximum assimilation rate (A_max), apparent quantum efficiency (A_q), carboxylation efficiency (C_e), superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), gibberellin A₃ (GA₃), and indole-3-acetic acid (IAA) were highest, while malondialdehyde (MDA) was lowest at 6°C DIF. At 25°C T_m, P_N, P_max, A_max, A_q, C_e, g_s, C_i, CAT, POD, GA₃, IAA, and zeatin reached the maximum under 6°C DIF, while SOD and MDA reached the maximum under 12°C DIF. Furthermore, the morphological index peaked at 6°C DIF under 18°C and 25°C T_m. The results suggested that 6°C DIF improved the growth and development of tomato during the flowering stage. ABBREVIATIONS: Aq – apparent quantum efficiency; Amax – the maximum assimilation rate; CAT – Catalase; Chl a(b) – chlorophyll a(b); Ca – ambient CO₂ concentration; Ce – carboxylation efficiency; Ci – intercellular CO₂ concentration; DIF – difference between day temperature (TD) and night temperature(TN); FM – fresh mass; gs – stomatal conductance; GA₃ – gibberellin A₃; IAA – indole-3-acetic acid; Ls – stomatal limitation value; MDA – malondialdehyde; Pmax – photosynthetic rate at irradiation saturation; PN – net photosynthetic rate; POD – peroxidase; ROS – reactive oxygen species; SOD – superoxidedismutase; Tm – daily mean temperature; ZT – zeatin.     

Responses of labile soil organic carbon and enzyme activity in mineral soils to forest conversion in the subtropics

Aims

Globally, extensive areas of native forest have been almost replaced by plantations to meet the demands for timber, fuel material and other forest products. This study aimed to evaluate the effects of forest conversion on labile soil organic C (SOC), soil respiration, and enzyme activity, and to quantify their relationship in subtropical forest ecosystems.

Methods

Surface mineral soil (0–20 cm) was collected from a Cunninghamia lanceolata Hook. plantation, Pinus massoniana Lamb. plantation, Michelia macclurei Dandy plantation, and an undisturbed native broadleaf forest. Soil microbial biomass C, dissolved organic C, permanganate-oxidizable C, basal respiration, and six enzyme activities were investigated.

Results

Soil microbial biomass C was higher by 45.9 % in native broadleaf forest than that in M. macclurei Dandy plantation. The ratio of soil microbial biomass C to total SOC was 27.6 % higher in the M. macclurei Dandy plantation than in the native broadleaf forest. The soil respiration increased by 25.2 % and 21.7 % after conversion from native broadleaf forest to P. massoniana Lamb. and M. macclurei Dandy plantations respectively. The effects of forest conversion on the soil enzyme activities differed among the tree species. Soil microbial biomass C had higher correlation with soil respiration than with the other SOC fractions. Moreover, soil microbial biomass C was positively correlated with urease and negatively correlated with cellulase activity. Soil respiration had higher correlation with soil microbial biomass C, dissolved organic C and permanganate-oxidizable C.

Conclusion

Forest conversion affected the soil microbial biomass C, soil respiration, invertase, cellulase, urease, catalase, acid phosphatase, and polyphenol oxidase activities, but their response depended on tree species. Soil respiration was mainly controlled by labile SOC, not by total SOC.     

生物质微米燃料富氧燃烧特性分析

采用热重分析法对生物质微米燃料在不同体积分数氧条件下的燃烧特性进行研究,结果表明:随着氧体积分数的增加,生物质微米燃料的挥发分初析出温度、着火温度和燃尽温度不断降低,可燃性增强;平均和最大质量损失速率呈增加趋势,提高了燃烧强度.燃烧特性指数随着氧体积分数的增加而变大,当氧体积分数达到60%后,改善趋势变缓.