施钾量对设施基质栽培番茄生长生理及其产量和品质的影响

以番茄品种‘184’为材料,采用水肥一体化番茄设施基质栽培模式,以甘肃农业大学植物营养液配方C中钾肥为对照(T₁常规钾肥量),再在配方C中添加不同量钾肥组成T₂(钾肥增量25%)、T₃(钾肥增量50%)、T₄(钾肥增量75%)等处理,探究不同施钾量对设施基质栽培番茄生长、生理、产量及品质的影响,并筛选设施基质栽培条件下最佳施钾量。结果显示：(1)与常规施钾肥量(T₁)相比,增施钾肥处理(T₂-T₄)均可显著提高番茄株高、茎粗、根系活力,且T₃处理的各指标均最高,但增施钾肥对叶片数的影响不显著。(2)增施钾肥处理较T₁均能够显著提高番茄叶片光合色素含量,增强光合和荧光过程,进一步促进光能的吸收与转化,且T₃处理的增幅最高。(3)随着施钾量的升高,增施钾肥处理的番茄单果重、果实产量呈现不同程度的增长趋势,适量增施钾肥处理增幅均达到显著水平,并以T₃番茄产量最高,且较T₁显著增产20.87%。(4)与T₁相比,各施钾处理番茄果实硬度、可溶性总糖、Vc、可溶性蛋白、番茄红素含量等均有不同程度提升,各指标均随着施钾量增加呈先上升后下降的变化趋势,并在T₃处理下达到最优。(5)主成分分析表明,各处理的综合得分依次为T₃＞T₄＞T₂＞T₁。研究发现,在设施基质栽培条件下,适量增施钾肥能显著提高番茄植株光合作用效率,促进植株生长,达到提高果实产量和改善品质的目的,并以常规钾肥增量50%处理的效果最佳。     

不同林分白蜡树云斑白条天牛种群空间格局地统计学分析

云斑白条天牛是我国重要林业害虫,在黄河三角洲地区对白蜡树造成严重危害。利用地统计学方法,通过调查城市行道绿化林、庭院绿化林、公路林和片林4种不同林分类型的白蜡树林地,以产卵刻槽、排粪孔和羽化孔为调查指标,对危害白蜡云斑白条天牛种群卵、幼虫、成虫(蛹)的空间格局进行了研究。结果表明:除片林样点成虫(蛹)的半变异函数模型为指数模型外,危害白蜡云斑白条天牛种群卵、幼虫、成虫(蛹)在不同林分类型下的半变异函数模型均为球形模型,其指明空间分布均为聚集分布,种群的聚集分布习性与林分类型相关性不强。但不同林分类型云斑白条天牛种群的空间相关性地统计学参数存在差异,片林调查样点的卵、幼虫和成虫(蛹)的变程a、块金值C0和基台值C0+C均小于其他3种林分类型的统计值,片林样点成虫(蛹)的半变异函数模型不同于其他林分类型为指数模型。     

Reactions Involved in the Lower Pathway for Degradation of 4-Nitrotoluene by Mycobacterium Strain HL 4-NT-1

In spite of the variety of initial reactions, the aerobic biodegradation of aromatic compounds generally yields dihydroxy intermediates for ring cleavage. Recent investigation of the degradation of nitroaromatic compounds revealed that some nitroaromatic compounds are initially converted to 2-aminophenol rather than dihydroxy intermediates by a number of microorganisms. The complete pathway for the metabolism of 2-aminophenol during the degradation of nitrobenzene by Pseudomonas pseudoalcaligenes JS45 has been elucidated previously. The pathway is parallel to the catechol extradiol ring cleavage pathway, except that 2-aminophenol is the ring cleavage substrate. Here we report the elucidation of the pathway of 2-amino-4-methylphenol (6-amino-m-cresol) metabolism during the degradation of 4-nitrotoluene by Mycobacterium strain HL 4-NT-1 and the comparison of the substrate specificities of the relevant enzymes in strains JS45 and HL 4-NT-1. The results indicate that the 2-aminophenol ring cleavage pathway in strain JS45 is not unique but is representative of the pathways of metabolism of other o-aminophenolic compounds.     

肿腿蜂类寄生蜂室内控害效能评价——以松脊吉丁肿腿蜂为例

为了开发利用天敌资源防治害虫,科学而客观地评价肿腿蜂对蛀干害虫的控害作用,研究了松脊吉丁肿腿蜂(Sclerodermus sp.)对松褐天牛3龄幼虫的功能反应,建立了肿腿蜂类寄生蜂室内控害效能评价体系,并证明了其可行性。该评价体系包括供试虫源标准、寄生蜂生物学与寄生行为学观察、寄生蜂对寄主的功能反应和寻找寄主效应以及寄生蜂的忠岐指数(Y)4个部分。研究结果表明:松脊吉丁肿腿蜂具有较强的控害潜力,单头雌成虫能防治3—4头松褐天牛3龄幼虫,21d内最多可致死9.07头寄主幼虫;寄主密度对单头寄生蜂寄生作用功能反应的测定结果与对寄生作用寻找效应的测定结果以及对产卵量影响的测定结果一致;综合评价该蜂对松褐天牛3龄幼虫控制效能,释放比为1∶1(即1头肿腿蜂雌蜂:1头3龄松褐天牛幼虫)时最高,其忠岐指数Y为39.63,这可能是肿腿蜂类天敌特有的抚幼习性所致,结论也与寄生蜂生物学特性及寄生行为学观察结果相同。研究结论证明该评价体系是稳定可靠的。评价体系在利用天敌昆虫生物防治害虫时为筛选最佳寄生性天敌种类提供了可行的方法和依据。     

Inhibitors of inosine monophosphate dehydrogenase: SARs about the N-[3-Methoxy-4-(5-oxazolyl)phenyl moiety

The first reported structure-activity relationships (SARs) about the N-[3-methoxy-4-(5-oxazolyl)phenyl moiety for a series of recently disclosed inosine monophosphate dehydrogenase (IMPDH) inhibitors are described. The syntheses and in vitro inhibitory values for IMPDH II, and T-cell proliferation (for select analogues) are given.     

Novel indole-based inhibitors of IMPDH: introduction of hydrogen bond acceptors at indole C-3

The development of a series of novel indole-based inhibitors of 5'-inosine monophosphate dehydrogenase (IMPDH) is described. Various hydrogen bond acceptors at C-3 of the indole were explored. The synthesis and the structure-activity relationships (SARs) derived from in vitro studies are outlined.     

Modeling uptake of cadmium from solution outside of root to cell wall of shoot in rice seedling

Barley (Hordeum vulgare L.) is well known for its relatively high salt tolerance among cereal crops. However, the genetic variation of cultivated barley becomes narrower due to continuous artificial selection and breeding processes. Compared with cultivated barley, wild barley contains wider genetic variation and abundant sources for abiotic stress tolerance, considering as an elite resource for mechanism study on salt tolerance. In this study, Tibetan wild barley accession XZ113 identified with high salt tolerance, was used to investigate ionic responses and to identify proteins involved in salt tolerance in roots and shoots at early stage of salt stress, during 48 h. Exposed to salinity, shoot growth is more sensitive than root growth. Conversely, K/Na ratio in the shoots was larger than that in the roots, and both were above 1.0. Steady-state K⁺ flux experiment showed XZ113 had a strong K⁺-retaining ability under salt stress, maybe contributing to its good performance of the absolute growth rate. Proteomic results suggested that monodehydroascorbate reductase and peroxidases related to reactive oxygen species scavenging in the roots and phosphoglycerate kinase, triosephosphate isomerase and sedoheptulose-1,7-bisphosphatase associated with photosynthesis and metabolisms in the shoots, played important roles in salt tolerance at early stage of salinity in wild barley.