套袋黄冠梨黑点病与钙素营养和果实衰老的关系

为探明套袋黄冠梨果实黑点病发病原因,从采后生理、矿质营养水平、酚类物质酶促褐变和果实衰老等方面对套袋黄冠梨果实黑点病进行了研究。结果表明:套袋果呼吸强度显著高于不套袋果;套袋果Ca含量仅为不套袋果的49%-63%,果皮钙素含量未套袋果>套袋健康果>套袋病果,套袋病果与不套袋果果皮N/Ca比值分别为9.8和6.1,K/Ca比值分别为17.6和8.8;果皮和果心酚类物质含量及多酚氧化酶活性(PPO)呈套袋病果>套袋健康果>未套袋果的趋势;套袋病果果皮丙二醛(MDA)含量及电导率显著高于未套袋果;果皮钙素含量与其PPO活性、多酚及丙二醛含量、电导率呈高度负相关。初步分析黄冠梨果实黑点病病因为缺钙性生理衰老。     

Ca~(2+)-ATPase抑制剂对采后草莓呼吸速率和花青苷含量的影响

用Ca2+-ATPase抑制剂钒酸钠(SO)和曙红(EB)浸泡处理转红期草莓果实(cv.Darselect)后表明,2者能提高果实呼吸速率,迅速促进外层果肉的花青苷生成,增加其可溶性糖含量,髓部果肉的花青苷生成和可溶性糖的变化较慢,而对果实的失重率影响不大。因此,Ca2+-ATPase抑制剂具有促进果实成熟衰老的作用。     

日光温室黄瓜栽培CO_2浓度的消长规律初探

近 3a(年 )的研究结果表明 :日光温室内CO2 浓度有明显的季节变化和日变化。在整个生长期内因通风时间和通风量的不同 ,日光温室内的CO2 浓度 11月和 3月较高 ,5月较低。各时期日变化基本相同 ,但变化幅度因季节而异 ,上午随Pn的逐渐增大而下降 ,中午 12 :0 0～ 14 :0 0时降至最低 ,下午又随Pn的减小而缓慢回升。叶片的光合作用、呼吸作用和土壤呼吸是影响日光温室内CO2 浓度日变化的主要因素。有机肥施用量对室内土壤呼吸和日光温室CO2 浓度有较大影响 ,在有机肥充足的条件下 ,室内CO2 浓度基本满足黄瓜光合作用的需要 ,无须补施 ,如果在作物生长期间再定时随水向土壤中冲施有机肥 ,效果就更好     

采收成熟度对牛肝菌保鲜贮藏的影响

不同成熟度的食用菌子实体采后生理、病理及贮藏品质有不同的变化规律 ,本文通过对美柄牛肝菌(BoletusspeciosuFrost)三种不同成熟度的子实体的呼吸强度、呼吸商的测定分析 ,及贮藏过程中菌体外观品质变化综合评定的产生及发展进行分析 ,为牛肝菌采集及贮藏中的原料标准的制定提供依据。     

Establishment of macro-aggregates and organic matter turnover by microbial communities in long-term incubated artificial soils

The study of interactions between minerals, organic matter (OM) and microorganisms is essential for the understanding of soil functions such as OM turnover. Here, we present an interdisciplinary approach using artificial soils to study the establishment of the microbial community and the formation of macro-aggregates as a function of the mineral composition by using artificial soils. The defined composition of a model system enables to directly relate the development of microbial communities and soil structure to the presence of specific constituents. Five different artificial soil compositions were produced with two types of clay minerals (illite, montmorillonite), metal oxides (ferrihydrite, boehmite) and charcoal incubated with sterile manure and a microbial community derived from a natural soil. We used the artificial soils to analyse the response of these model soil systems to additional sterile manure supply (after 562 days). The artificial soils were subjected to a prolonged incubation period of more than two years (842 days) in order to take temporally dynamic processes into account. In our model systems with varying mineralogy, we expected a changing microbial community composition and an effect on macro-aggregation after OM addition, as the input of fresh substrate will re-activate the artificial soils. The abundance and structure of 16S rRNA gene and internal transcribed spacer (ITS) fragments amplified from total community DNA were studied by quantitative real-time PCR (qPCR) and denaturing gradient gel electrophoresis (DGGE), respectively. The formation of macro-aggregates (>2 mm), the total organic carbon (OC) and nitrogen (N) contents, the OC and N contents in particle size fractions and the CO₂ respiration were determined. The second manure input resulted in higher CO₂ respiration rates, 16S rRNA gene and ITS copy numbers, indicating a stronger response of the microbial community in the matured soil-like system. The type of clay minerals was identified as the most important factor determining the composition of the bacterial communities established. The additional OM and longer incubation time led to a re-formation of macro-aggregates which was significantly higher when montmorillonite was present. Thus, the type of clay mineral was decisive for both microbial community composition as well as macro-aggregation, whereas the addition of other components had a minor effect. Even though different bacterial communities were established depending on the artificial soil composition, the amount and quality of the OM did not show significant differences supporting the concept of functional redundancy.     

返青期休牧对退化高寒草地植被特征及优势种光合生理的影响

为探讨返青期休牧对退化高寒草地植被特征及优势种光合生理的影响,本研究在祁连山区选择已实施返青期休牧6年的高寒草甸开展了植被特征及优势种光合生理相关指标的调查研究。结果表明：返青期休牧6年后,高寒草甸的植被盖度、地上生物量、地下生物量和土壤含水量较未休牧区分别增加了38.44%,985.00%,209.56%和62.62%,其优势禾草垂穗披碱草（Elymus nutans）株高、叶片净光合速率、光化学量子效率、呼吸速率、叶面积、相对叶绿素含量和叶片氮含量分别提高了965.77%,139.86%,4.92%,269.37%,254.13%,197.02%和96.24%（P<0.05）,其地上地下生物量与除叶温和光化学猝灭系数外的指标显著相关,叶片净光合速率与除叶温外的指标显著相关。因此,返青期休牧可显著增强高寒草地优势禾草的光合作用和呼吸作用,促进植物生长及退化草地的恢复。本研究为推广实施返青期休牧这一措施来恢复退化高寒草地植被提供了理论基础。     

菌丝生长速度与呼吸消耗及胞外酶活性的关系

以棉籽壳为主料,对平菇、刺芹侧耳、黄伞、灵芝、金针菇和香菇原种培养期间的菌丝生长速度、呼吸消耗及胞外酶活性的关系进行了研究。结果表明,6种食用菌的菌丝生长速度与呼吸消耗正相关,而有机物的降解速率与胞外酶活性的大小没有相关性。     

鸡巨型艾美耳球虫卵囊呼吸作用的研究

采用纯种巨型艾美耳球虫(Eimeria maxima)卵囊,人工感染3周龄的石歧杂雏鸡,及时收集卵囊,以0.1N硫酸溶液悬浮,用微量呼吸检压仪检测卵囊呼吸作用。试验表明:孢子化过程中最初十小时内该球虫卵囊的耗氧量为3.59μl/小时/10~6个卵囊。耗氧量的变化与其细胞分裂过程相对应,耗氧量在三次核分裂前夕降低,但在分裂期升高。最高耗氧量出现于子孢子形成期,达18.91μl/小时/10~6卵囊。孢子化后卵囊的呼吸作用较缓慢,耗氧量为0.85μl/小时/10~6个卵囊。完成孢子化所需时间为26小时。