Effects of Soil Drought in the Generative Phase of Development of Field Bean (Vicia faba L. var. minor) on Leaf Water Status, Photosynthesis Rate and Biomass Growth

The effects of 10-day periods of soil drought during flowering (DI) or pod growth (DII) and during both these phases (DI + DII) on leaf water status, photosynthesis rate, plant growth and production of biomass was studied in pot experiments with field bean. Soil water content during drought spells were kept at 30% of field water capacity. Soil water deficiency DI and DII depressed the leaf water potential relatively to control by about 100 % and 140 % respectively, increased the water deficit by 100 % and 120 % and reduced photosynthesis rate by 80 % and 90 %. Rehydration of tissues completely abolished any decline of photosynthesis rate caused by drought DI, but after drought DII photosynthesis rate remained depressed by about 30 % even after rehydration. Drought periods DI and DII caused more rapid withering of leaves, a decline in the total leaf area and a temporary increase of root weight.
Drought occuring at flowering (DI) also activated the mechanism of plant adaptation to water deficiency during the pod formation phase (DII). Single or double periods of drought had not any significant influence on the number of pods and seeds, but decreased their weight.     

模拟间伐对树冠直径方差发生机制的研究

有些收获表的主林木直径方差为负值，这在理论上是矛盾的。原因之一是在编制收获表的过程中，假定所有主林木的直径相同，没有考虑直径分布。该文在若干假定的前提下，在林木开始竞争时，通过模拟间伐，从理论上探讨树冠直径方差发生机制。     

甜樱桃品种吉列玛叶片再生不定梢的研究

在基本培养基NN69或WPM上附加BA和低浓度的NAA，IAA，IBA作培养基，诱导甜樱桃品种吉列玛试管苗的叶片产生了不定梢。以WPM附加BA 3mg/L和IAA0．3mg/L的处理，不定梢再生率最高为33．3％。     

冷冬对美洲斑潜蝇越冬及发生趋势的影响

研究表明：在冷冬条件下，美洲斑潜蝇仍可安全越冬，但其在春季的发生推迟。冷冬对美洲斑潜蝇夏秋季发生趋势无影响。入梅的早迟，雨量的大小，雨日的多少，作物布局及长势，栽培方法等，是影响其夏秋季发生为害的主要因子，可在测报与防治上加以应用。     

Appresoorium formation of Puccinia hordei on partially resistant barley and two non-host species

One of the components of partial resistance of barley to leaf rust,Puccinia hordei, is a reduced infectibility. It was investigated whether this low infectibility may rest on a hampered appressorium formation of the leaf rust fungus. The appressorium formation on the primary leaves of 11 barley genotypes with an intermediate-to-low infectibility was compared with that on the highly infectible L94. The number of stomata per cm² leaf area occupied by appressoria ofP. hordei was determined per genotype by means of fluorescence microscopy. No cosistent differences could be detected, indicating that the mechanisms causing a low infectibility of partially resistant barley seedlings act at a phase later than the formation of the appressoria. On the non-host wheat not fewer appressoria were formed than on L94, but no appressoria were found on a lettuce genotype. The latter probably lacks the stimuli that enable the fungus to find stomata.Samenvatting Eén van de componenten van partiële resistentie van gerst tegen dwergroest,Puccinia hordei, is een verminderde infectiedichtheid. Het mechanisme, dat hieraan ten grondslag ligt, is onbekend. Een experiment werd uitgevoerd om na te gaan of bij partieel resistente rassen een verminderde appressoriumvorming optreedt. Na inoculatie in een inoculatietoren en een zorgvuldig uitgevoerde incubatie werd het aantal huidmondjes per cm² bladoppervlak bepaald dat bezet was door appressoria vanP. hordei. De elf weinig vatbare gerstlijnen uit deze studie bleken niet reproduceerbaar te verschillen van de zeer vatbare gerstlijn L94 in de mate van appressoriumbezetting. Dit wijst erop dat infectiedichtheidsverschillen t.g.v. partiële resistentie veroorzaakt worden door mechanismen die werken na de appressoriumvorming. In een tweede experiment werd aangetoond dat zelfs op de niet-waardsoort tarwe, waaropP. hordei geen symptomen veroorzaakt, niet minder appressoria worden gevormd dan op L94. Op een sla-genotype trad echter geen appressoriumvorming op. Op deze laatste niet-waardsoort ontbreken waarschijnlijk de stimuli die de schimmel in staat stellen huidmondjes te vinden.     

Dynamic climate control; an optimization study for earliness of cucumber production

The culture of a cucumber crop can be divided into two stages: growth of young plants until flowering, and fruit production. The first stage should be as short as possible to minimize the costs during the vegetative phase. In the present study, a simple optimization model was tested. The model quantifies the instantaneous effect of environmental factors on earliness of production using the number of leaves as a characteristic parameter related to the onset of the production stage. The temperature in the glasshouse was optimized by maximizing the difference between the rate of economic production and the rate of energy consumption.In a glasshouse experiment, it appeared that effects of light and temperature on the leaf unfolding process differ. Whereas the leaf unfolding rate responds rapidly to a change in temperature, changes of light intensity give rise to a considerably delayed response. The effect of light intensity during the time prior to planting appears to be of significant importance to the leaf unfolding rate in the subsequent period from planting until flowering.     

苦瓜平脐蠕孢叶斑病病原鉴定

This study was conducted to identify the pathogens causing a new leaf spot disease on bitter gourd. The diseased leaves were collected from bitter gourd plantations around Nanning, Guangxi province. The pathogen causing this disease was identified by pathogenicity, morphology, and combined gene sequences analysis on ITS, TEF and GPD. The morphological characteristics of the pathogen were similar to that of Bipolaris bicolor. The representative isolate was clustered into one clade in phylogenetic tree with B. bicolor, which indicated that the leaf spot of bitter gourd was caused by B. bicolor. This is the first report of a leaf spot disease caused by B. bicolor on bitter gourd.     

玉米新月弯孢叶斑病研究进展

 玉米弯孢叶斑病是一种世界性玉米病害,也是中国玉米产区的主要病害之一。20多年来,国内外在该病害发生规律、致病性分化与诱导抗性机理、生物防治技术等方面开展了深入研究。本文主要就该病害优势致病菌新月弯孢菌 [Curvularia lunata (Wakker)Boedijn]的生物学特性、致病因子与生理分化机理、毒素结构鉴定、毒素合成与调控、诱导抗病性分子机理等方面的研究进展进行综述,以期对玉米弯孢叶斑病防控技术的创新提供参考。     

肺癌腔内后装治疗方法改进的研究

对７０例肺癌患者随机分为两组，用改进麻醉及插管方法与常规方法作了对经研究，结果表明：在改进法组中，患者剧烈咳嗽，支气管痉挛和咯血等并发症明显减少，并对两组并发症的治疗作了讨论。