Conidiogenous loss of structuro-functional polarity in the hyphal tips of Sclerotinia fructigena

Ultrastructural depolarization in the conidiogenously induced hyphal tips is initiated by Spitzenk?rper (apical body) disintegration, followed by spreading of wall-associated vesicles and migration of mitochondria and lipid granules into the exclusion zone of the vegetative apices.     

不同光照度对3种藻生长的影响（简报）

不同光照度和相同的最适营养、温度(25±1)℃以及光周期(12h/12 d)培养铜绿微囊藻、多变鱼腥藻和斜生栅藻的实验结果表明,在15 000 lx和21 000～25 000 lx的光照度下,3种藻的比增长率和现存量最高.15 000 lx是铜绿微囊藻和多变鱼腥藻生长的最适光照度,21 000～25 000 lx是斜生栅藻生长的最适光照度范围.     

Effect of Storage in Darkness and in Light on the Content of Membrane Lipids of Potato Tubers

The lipid composition of tubers from the potato varieties Bintje and Desirée was investigated during storage. Storage in total dark ness after harvest gave only small changes in the amounts of triglycerides. monogalactosyl diglycerides and digalactosyl digtycerides. Storage in light resulted in changes in these lipids and in their fatty acid composition. The absolute amount and the relative content of linolenic acid in the galactolipids increased. A simultaneous and equivalent decrease in the percentage of linoleic acid took place without any marked percentage changes in the other major fatty acids. The light induced changes of the lipids, which occur simultaneously with greening of the tuber, are discussed and related to the development of thylakoid membrane systems in the plastids.     

Changes in the Growth of Salvinia natans Induced by Cycles of Light and Darkness of widely Different Duration

The growth of Salvinia natans has been examined when clonalmaterial, maintained at a constant temperature (30 ^°C) receivesthe same amount of light energy per day but where the light-darkcycle of equal intervals varies in eight steps from 1 min to12 h. The area per leaf, the rate of leaf production, the netassimilation rate, and the relative growth-rate increase withthe lengthening of the cycle, but the leaf-area ratio is reduced.The magnitude of the changes differs between the criteria whilethe order of the response may be disparate between consecutiveintervals. In supporting experiments the same measurements weremade on plants subjected to a wide range of light intensitieswith a common photoperiod of 12 h. Here decreasing light intensityproduces similar trends to those recorded for increasing thelength of the cycle but the patterns of response may diverge.It was also established that the size of the stomatal pore isthe same in the light and in the dark. It is postulated thatvanations in the light-dark cycle may influence both the levelof photosynthetic activity and the pathways.     

The Effect of Light and Darkness Upon Infection of Asterionella formosa Hassall by the Chytrid Rhizophydium planktonicum Canter emend

Observations, both experimental and microscopic, indicate thatzoospores of Rhizophydium planktonicum Canter emend., can remainalive, but rarely become adherent upon cells of Asterionellaformosa Hassall under conditions of very low light or in completedarkness. The behaviour patterns of zoospores towards host cells underdarkened conditions were compared with those which took placeunder well illuminated conditions leading to the settlementof zoospores on host cells. The differences noted may help toexplain the lack of zoospores found upon inadequately illuminateddiatom cells. Some evidence suggests that young zoospores lack the abilityto adhere to host cells. After the encystment of zoospores uponAsterionella cells in the light, their further growth and developmentcan continue in darkness. Rhizophydium planktonicum Canter emend., Asterionella formosa Hassall, chytrid, diatom, infra-red illumination, zoospore     

Mechanisms of Photoreceptor Current Generation in Light and Darkness

PENN and Hagins first demonstrated a sustained “dark” voltage along the axis of rat retinal rods which results from membrane current leaving the inner segment and entering the outer segment^1,2. They also found that the response to light (receptor potential) is a reduction in this “dark” voltage which does not alter its spatial distribution. I have examined the retinal “dark” voltage and the light-evoked receptor potential in terms of possible passive and active transport mechanisms of electrogenesis.     

袋口高度、光照、CO2等因子对杏鲍菇工厂化栽培的影响

.8%～0.97%,该浓度下杏鲍菇子实体发育正常.     

Studies in the Physiology of Parasitism: XX. The Pathogenicity of Botrytis cinerea, Sclerotinia fructigena, and Sclerotinia laxa, with special reference to the part played by pectolytic enzymes

1. Though Sclerotinia fructigena, S. laxa, and Botrytis cinereacause rotting of apple tissue and death of the protoplasts,little or no pectolytic activity was detectable in extractsof the rotted tissue. 2. Pectic materials were extracted from normal and parasitizedapple tissue in three fractions and precipitated as calciumpectate. There was a loss of total, total insoluble, and solublepectic substances in the invaded tissues. This was most markedwith B. cinerea and S. laxa and least with S. fructigena. 3. Pectolytic activity was measured by methods involving (a)maceration of plant tissues, (b) viscosity and reducing groupdeterminations in pectic substrates, (c) increase in acidityof pectin. By these methods it was shown that pectolytic enzymeswere produced by all three fungi in synthetic media. With S.fructigena, which was the only fungus studied in detail, replacementof glucose by pectin increased the formation of pectolytic enzymes. 4. When various apple extracts were used as culture media, littleor no pectolytic activity was detectable. With all three fungithe presence of apple juice in a culture medium, which by itselfwas suitable for enzyme formation, resulted in the suppressionof pectolytic activity. 5. Oxidized apple juice had a pronounced effect in deactivatingcertain pectolytic enzymes, an effect which was especially markedwith B. cinerea. This points to an interaction between the pectolyticand oxidizing systems and introduces a new line of approachto the study of the biochemical interaction between host andparasite.     

The Effect of Growth-regulating Substances and Light on Olive Callus Growth in vitro

In vitro olive callus cultures were established; auxin was notobligatory for the early development of the callus. However,after a number of subcultures, both an auxin and a cytokininwere needed for growth. IAA was the most efficient auxin ininducing growth, although 2,4-D was also very active. Very shortperiods of red-light illumination were sufficient to effectgreening of the tissue. A particularly high ratio of chlorophyllb/a was found under all light conditions tested. All light treatmentsstimulating chlorophyll synthesis caused a reduction in growthafter four subcultures.     

不同光强对薇甘菊生长及光系统的影响

为了控制薇甘菊的生长和危害,对不同照度条件下薇甘菊的生长及光系统进行了测定.分别采用光强40μmol·m-2·s-1(处理Ⅰ);上午自然光,下午照度为40μmol·m-2·s-1(处理Ⅱ);全自然光(处理Ⅲ)处理薇甘菊.结果表明对薇甘菊处理2个月后,处理Ⅰ条件下,薇甘菊生长差,生物量积累少,光系统Ⅰ和光系统Ⅱ的光能转换效率和潜在活性较低,可溶性糖和蛋白质含量较低,细胞膜脂脂肪酸组成中不饱和脂肪酸含量相对较高;在处理Ⅱ和处理Ⅲ条件下,则生长茂盛,生物量积累多,光系统Ⅰ和光系统Ⅱ的光能转换效率和潜在活性较高,可溶性糖和蛋白质含量较高,细胞膜脂脂肪酸组成中不饱和脂肪酸含量相对较少.这些结果说明光照多方面影响薇甘菊光系统功能的形成,从而影响其生长.     

单色光对小麦草生长速率的影响研究

通过LED光照实验,探究不同光质和光周期对小麦草生长速率的影响。采用大功率红、蓝LED灯,红光峰值波长为655 nm,蓝光峰值波长为438 nm。实验采用控制变量法,以光质和光周期为变量,其余生长环境保持一致。结果表明:红光照射下生长速率要明显优于蓝光,甚至超过室内日光。在红蓝复合光中,红光光强高于蓝光时,更利于小麦草生长;连续24 h的光照与间隔12 h的光照相比,略有生长优势。