AN ANALYSIS OF THE GROWTH RESPONSE OF YOUNG TOMATO PLANTS TO INFECTION BY VERTICILLIUM ALBO-ATRUM: II. THE PRODUCTION OF GROWTH SUBSTANCES

Bioassays on ether-soluble acid extracts from healthy and Verticillium -infected tomato plants, showed the presence of substances inhibiting growth of wheat coleoptiles in both healthy and infected leaves and stems, but the amounts were greater in the infected.
Assays of infected stems and leaves showed increases in growth-promoting activity expressed as indole-3-acetic acid equivalents (IAAe), up to 200% of those for healthy controls.
Similar assays of cultures of V. albo-atrum showed growth-promoting activity. No acid substance capable of inhibiting the growth of wheat tissue was detected in the culture filtrate. IAA was identified by colour test with Ehrlich's reagent on chromatograms from extracts of both infected stems and fungal culture filtrates.
The vertical distribution of IAAe was determined in healthy and infected plants at the eight-leaf stage by assaying individual leaves and four stem segments separately. In healthy plants the IAAe content was greatest in the young leaves (6–8) but no gradient was observed as between leaves 1–5. In infected leaves increases over the controls were found in leaves, 1, 3 and 6 and a decrease in leaf 8.
In healthy stems IAAe was highest in the distal segment and infected stems showed higher values at all four levels, with the relative increase greatest in the distal region.
It is suggested that the major part of the Verticillium syndrome including petiolar epinasty, tylosis, pith hyperplasia and the formation of adventitious roots is the result of an accumulation of growth substances in infected tissue.     

Metabolic disturbances innicotiana glauca,a symptomless

Metabolic disturbances inNicotiana glauca, a symptomless carrier of potato witches’ broom were studied. The dry weight content of leaves of diseased plants was slightly decreased, that of the stems increased. The ash content in the dry weight of the whole diseased plant was decreased by 11%. Contrary to tomato plants which had shown considerable disproportions in the distribution of metabolites among the individual organs investigated (ULRYCHOVÁ, LIMBERK 1964), the content of the total nitrogen and of the individual nitrogen fractions of both leaves and stems of diseasedNicotiana glauca were decreased. The content of glutamine was increased in both organs in spite of the decrease of ammonia nitrogen by nearly 30% in both cases. The most striking disturbance found in the diseased plants ofNicotiana glauca was the 67% increase of a low-molecular phosphorus fraction (P extractable with 0-2N HCIO₄) in the leaves. This result agrees with that found in diseased tomato plants and may be primarily associated with the virus infection. The content of all other phosphorus fractions of both leaves and stems was decreased.     

粗缩病对玉米产量和籽粒品质的影晌

以6个对玉米粗缩病（MRDV）表现不同抗性的玉米品种为材料,研究了粗缩病对玉米产量性状和籽粒品质的影响。结果表明,在供试品种中,‘青农105’和‘青农8’为抗病品种,‘登海3622’和‘农大108’为中抗品种,‘先玉335’和‘郑单958’为感病品种。感病后,玉米果穗穗长、行粒数、穗粒重和产量显著降低,且损失程度表现为抗病品种〈中抗品种〈感病品种：籽粒中粗淀粉含量显著降低,粗蛋白含量升高,粗脂肪含量变化不明显。回归分析表明,通过旃情指数可以准确预测玉米粗缩病导致的产量损失。     

Photosynthesis in Sugarcane Varieties Infected with Strains of Sugarcane Mosaic Virus

Symptoms of sugarcane mosaic virus disease caused by strains B and D were accompanied by a reduction in the rate of photosynthesis per unit area; the severe symptoms of strain A and the mild symptoms of strain I produced rates no different from those of healthy plants of variety C.P. 31-588. All four strains decreased chlorophyll content and increased the amount of light transmitted by the leaf. Photosynthetic rates were reduced less than the reduction of chlorophyll would indicate. Symptoms moderated on older leaves, but rates of photosynthesis per dm² were less in older leaves of both healthy and diseased plants. Sugarcane varieties differed in their rates of photosynthesis in both healthy and in virus-infected plants; a significant reduction in photosynthetic rate by sugarcane mosaic occurred in three of the four varieties.     

PHYSIOLOGICAL STUDIES ON THE VERTICILLIUM WILT DISEASE OF TOMATO

The water loss per unit leaf area of tomato plants was decreased after inoculation with Verticillium albo-atrum. When diseased plants began to wilt water loss temporarily increased, but then rapidly decreased to become less than that of healthy plants grown under conditions of adequate or restricted water supply.
The transpiration of excised leaves from plants grown with a restricted water supply was reduced, but not so severely as that of comparable leaves from infected plants. Water loss from leaves on infected plants was reduced irrespective of any blocking of the petiolar xylem.
The rate of water loss from turgid leaf disks on mannitol solutions, and the rate of water uptake of leaf disks on water was similar for disks cut from wilting or turgid leaves of diseased plants or healthy plants grown with an adequate or restricted water supply.
Disease or poor water supply reduced leaf growth but had no effect on the rate of leaf initiation. Although the density of stomata was higher on leaves of diseased plants the stomatal area was less than on healthy plants.
The resistance to water flow in diseased stems was high and was correlated with vessel blockage. About half the blocked vessels contained hyphae. The severity and localization of symptoms in inoculated plants growing on susceptible or resistant rootstocks was directly related to the extent of invasion by the pathogen and to vessel blockage.
Experiments on the wilting activity of cell-free filtrates from cultures of the pathogen in vitro indicated that it produced a stable substance, not an enzyme, that caused wilting in cut shoots by blocking the end of the stem. It is suggested that an increasing internal water shortage causes major symptoms of disease.     

Transpiration in potato plants infected with Verticillium spp

Potato plants (cv. King Edward) infected with Verticillium albo-atrum and with V. dahliae transpired more slowly than healthy plants; this difference increased as the disease progressed. Diurnal fluctuations in transpiration were smaller in infected plants than in controls because infection markedly reduced water loss during the normal daytime peak period. Transpiration at night was unaffected by infection.
Both stomatal and cuticular transpiration of single, detached leaves were reduced by infection. A linear correlation was obtained between 'water saturation deficit' and transpiration rate in both diseased and healthy plants until the leaves wilted, suggesting that reductions in the stomatal rate are a consequence of the greater water deficits found in diseased plants, the differences in cuticular rates probably being due to anatomical differences between healthy and diseased leaves.
Close parallels between transpiration and water deficit indicate that in diseased plants water loss is largely determined by leaf water content. Thus wilting, commonly seen as a symptom of infection, is not the result of excessive water loss but follows a reduction in the supply of water to the leaves.
The author thanks Professor I. Isaac of this department and Dr G. C. Evans of the Botany School, Cambridge for their advice. The research was sponsored by the Potato Marketing Board.     

Some metabolic disturbances in tomato plants infected with potato witches’ broom

The pathophysiology of tomato plants infected with potato witches’ broom was studied. Changes in dry weight, content and composition of ash and the amount of different phosphorus and nitrogen fractions were investigated. All analyses were carried out separately in leaves, stems and preliminarily also in flowers. Considerable disproportions found in the distribution of metabolites among the individual organs investigated correspond to a great extent to the morphological picture of the disease. The leaves of diseased plants are actually starving and their growth and development are greatly inhibited. On the other hand, the stems are overflowing with metabolites, in particular with nitrogenous ones. They are thickened and along their entire length rootlets and sprouts appear forming the characteristic brooms. The authors assume that the disturbances in flower formation in diseased plants are due to the lack of essential metabolites. Diseased plants contain an increased amount of alkaline metals and alkaline earths.     

Water relations of rough lemon (Citrus jambhiri Lush.) citrus seedlings infected withFusarium solani

Summary Rough lemon citrus seedlings were inoculated withFusarium solani and evaluated for changes in water relations of leaves, stems, and roots. Inoculated seedlings had decreased leaf stomatal conductance, lower leaf water potential, lower water content, and higher leaf osmotic values compared to healthy plants. Visible wilt symptoms occurred as early as 24 h after inoculation. Transpiration and root conductivity were lower in diseased plants but stem conductivity in diseased plants did not differ from the control. Thus, wilting appears to be due to the inability of roots to supply water to the leaves.     

管氏肿腿蜂雌性抚育中幼虫转移行为的启动和节律

为深入理解肿腿蜂雌性抚育的行为学特征, 在室内连续观察了雌性管氏肿腿蜂Sclerodermus guani对子代幼虫的转移行为, 旨在明确雌蜂在子代蜂幼虫发育到哪一阶段时启动转移行为, 以及幼虫转移行为是否有节律。以黄粉虫Tenebrio militor蛹期在24 h内的蛹体为寄主, 根据子代蜂幼虫发育进程将其划分为低龄幼虫（1-2龄）、 高龄幼虫（3-4龄）、 老熟幼虫(自然脱落)和吐丝幼虫（开始吐丝结茧）等4个时期, 采取人工剥离（早期幼虫）或自然脱离（晚期幼虫）的方法处理子代蜂幼虫, 观察雌蜂对所表现出的行为反应; 然后以子代蜂高龄幼虫为对象, 连续观察雌蜂的30次幼虫转移行为过程。结果表明： 雌蜂对所有发育时期子代蜂幼虫均用触角拍打进行探测; 但不转移低龄幼虫, 只转移其他阶段幼虫, 转移老熟幼虫和吐丝幼虫的瞬间概率分别是转移高龄幼虫的4.09倍和7.69倍。雌蜂转移高龄、 老熟和吐丝幼虫的比例分别为96%, 100%和100%, 没有显著差异（P≥0.05）; 对高龄幼虫、 老熟幼虫和吐丝幼虫转移耗时平均分别为27.96, 34.04和32.49 s, 没有显著差异（P≥0.05）; 平均转移距离依次为4.19, 7.18和 9.43 mm, 对吐丝幼虫的转移距离显著大于高龄幼虫（P<0.05）, 但在高龄和老熟幼虫之间没有显著差异（P≥0.05）。对雌蜂连续30次幼虫转移行为的趋势和节律分析表明： 幼虫转移前探测的幼虫数总体上随幼虫转移次序增加而减少, 在间隔1次和2次之间存在显著自相关, 幼虫转移耗时在间隔1次之间存在显著自相关, 但幼虫转移距离未表现出明显的节律。本研究结果说明, 管氏肿腿蜂雌性抚育中的幼虫转移行为只在子代蜂幼虫发育到较高龄期时启动, 且幼虫转移中的某些行为特征具有节律性。     

Detrimental effect of rust infection on the water relations of bean

Bean plants (Phaseolus vulgaris L.) infected with the rust Uromyces phaseoli became unusually susceptible to drought as sporulation occurred. Under the conditions used (1,300 ft-c, 27 C, and 55% relative humidity) such plants wilted at soil water potentials greater than −1 bar, whereas healthy plants did not wilt until the soil water potential fell below −3.4 bars. Determinations of leaf water and osmotic potentials showed that an alteration in leaf osmotic potential was not responsible for the wilting of diseased plants. When diffusive resistance was measured as a function of decreasing leaf water content, the resistance of healthy leaves increased to 50 sec cm⁻¹ by the time relative water content decreased to 70%, whereas the resistance of diseased leaves remained less than 8 sec cm⁻¹ down to 50% relative water content. Apparently, water vapor loss through cuticle damaged by the sporulation process, together with the reduction in root to shoot ratio which occurs in diseased plants, upset the water economy of the diseased plant under mild drought conditions.     

Effect of ascochyta blight (Mycosphaerella pinodes) on yield components of single pea (Pisum sativum) plants under field conditions

Field studies were made in 1992 and 1993 to examine the yield components of pea inoculated with Mycosphaerella pinodes and those of healthy pea (sprayed with a mixture of flutriafol + chlorothalonil), in a split-plot design with the cv. Solara sown at different plant densities. Ascochyta blight was severe on leaves and on internodes of the basal part of the plants; pods had few lesions. The number and length of stems per plant were the same for diseased and healthy plants. The number of reproductive nodes and pods per stem were affected by disease only in 1993. In 1992 and 1993 respectively, disease caused reductions in the number of seeds per stem of 18% and 25%, and in seed size of 13.5% and 16.7%, compared with healthy plants. The harvest index and total biomass were lower in diseased than in healthy plants and seed yield was reduced by 40% in diseased plots. These results show a high relationship between the disease parameters (disease mean on stipules/nodes 8–18/ and on internodes/nodes 5–15/, percentages of stipules or internodes with a disease score 4, and percentage of stems encircled by lesions), plant density and yield reduction.     

Nutritional values in the diet of white-lipped peccary Tayassu pecari (Artiodactyla: Tayassuidae) in Corcovado National Park, Costa Rica

We determined the potential nutritional levels in 25 species of plants, and in earthworms, that constitute part of the diet of white-lipped peccary (Tayassu pecari) in Corcovado National Park, Costa Rica, from January 1998 to March 1999. The highest content of fat and energy was found in seeds of the Myristicacea family. The highest content of calcium was found in vegetative parts of Dieffenbachia spp. Nutritious contents differed among plant parts (seeds, fruits, stems and leaves). Fat and energy content were larger in seeds and fruits, whereas the largest content of protein was found in fruits and leaves. Mineral content also differed among plant parts. Calcium, potassium and magnesium were higher in leaves whereas copper and zinc were higher in seeds. Differences of diet between white-lipped peccaries in Corcovado and in other tropical regions of Latin America could be partially explained by our results. We found several species with higher fat and energy content than palms, which can explain the low consumption of palm seeds in Corcovado. It is possible that the regular consumption of stems and leaves of some species is related to their high mineral content. Seasonality of reproduction in Corcovado seems to be related not only to fruit availability but also to the nutritional quality of food.     

我国南方花生发生一种由蕃茄斑萎病毒引起的新病害

我们于1984和1985年6月上、中旬,在广州市郊、县,湛江市郊以及广西南宁市郊、县,北海市郊和合蒲县等花生产区,调查花生病毒病时,除了发现花生轻斑驳病毒病外,还发现一种新的病毒病害。其症状特征是:病株顶端叶片上出现很多褪绿黄斑或环斑,有的环斑变     

Ferulic acid may prevent infection of Cicer arietinum by Sclerotium rolfsii

High performance liquid chromatography analysis of different parts of Sclerotium rolfsii-infected and healthy seedlings of chickpea (Cicer arietinum) was carried out to examine the status of phenolic compounds. Three major peaks that appeared consistently were identified as gallic, vanillic and ferulic acids. Gallic acid concentrations were increased in the leaves and stems of infected plants compared to healthy ones. Vanillic acid detected in stems and leaves of healthy seedlings was not detected in infected seedlings. There was a significant increase of ferulic acid in those stem portions located above the infected collar region compared to minimal amounts in the roots of healthy seedlings. In vitro studies of ferulic acid showed significant antifungal activity against S. rolfsii. Complete inhibition of mycelial growth was observed with 1000 g of ferulic acid/ml. Lower concentrations (250, 500 and 750 g/ml) were also inhibitory and colony growth was compact in comparison with the fluffy growth of normal mycelium. Higher amounts of phenolics were found in the stems and leaves of S. rolfsii-infected seedlings in comparison to the healthy ones. A role for ferulic acid in preventing infections by S. rolfsii in the stems and leaves of chickpea plants above the infection zone is therefore feasible.     

福建蔗区甘蔗斐济病毒的鉴定

甘蔗斐济病毒(Sugarcane Fiji disease Virus,FDV)最早于1910年由Lyon等在斐济岛和新几内亚等地发现。其后,澳大利亚、马达加斯加、所罗门群岛、印度尼西亚、海布里地群岛、马来西亚、菲律宾以及泰国等的蔗区均有发生。我国各蔗区以前未见报道。但自1981年以来,福建多个蔗区还曾多次反映有疑似甘蔗斐济病病株出现,1982～1984年     

Respiratory potential and Se compounds in pea (Pisum sativum L.) plants grown from Se-enriched seeds

Selenium (Se) has been proved to be an essential element for humans and animals. However, less is known about its effects on plants. Pea plants were treated foliarly once (OT) and twice (TT) with Se solution during their flowering period. Seeds obtained from these plants contained 383 and 743 ng Se g(-1), respectively, and, together with control seeds from untreated plants (UT) containing 21 ng Se g(-1), were sown in soil in a greenhouse. Se content and its chemical form in young plants were studied, and its impact on plant respiratory potential, measured as terminal electron transport system (ETS) activity, determined. ETS activity was highest in young pea leaves with the highest Se content. Higher ETS activity possibly reflected increased glutathione peroxidase (GSH-Px) activity in mitochondria. The Se content of leaves and stems of plants grown from control seeds was similar to that in the seed, being around 40 ng Se g(-1). Se concentration in leaves of young plants grown from OT and TT seeds was 605%, and 1340% higher, respectively, than the control, and in their stems 355%, and 680% higher, respectively. The ratio of Se concentrations in OT and TT seeds was the same as in the leaves and stems in the young plants grown from them. SeMet was the major Se compound in Se-rich pea seeds and leaves, comprising 49% and 67% of the total Se content in OT and TT seeds, respectively, and 85% and 79% in the corresponding leaves.     

Composition and content of glucosinolates in developing Arabidopsis thaliana

The glucosinolate composition and content in various tissues of Arabidopsis thaliana (L.) Heynh. ecotype Columbia during development from seeds to bolting plants were determined in detail by high-performance liquid chromatography. Comparison of the glucosinolate profiles of leaves, roots and stems from mature plants with those of green siliques and mature seeds indicated that a majority of the seed glucosinolates were synthesized de novo in the silique. A comparison of the glucosinolate profile of mature seeds with that of cotyledons indicated that a major part of seed glucosinolates was retained in the cotyledons. Turnover of glucosinolates was studied by germination of seeds containing radiolabelled p-hydroxybenzylglucosinolate (p-OHBG). Approximately 70% of the content of [14C]p-OHBG in the seeds was detected in seedlings at the cotyledon stage and [14C]p-OHBG was barely detectable in young plants with rosettes of six to eight leaves. The turn-over of p-OHBG was found to coincide with the expression of the glucosinolate-degrading enzyme myrosinase, which was detectable at very low levels in seedlings at the cotyledon stage, but which dramatically increased in leaves from plants at later developmental stages. This indicates that there is a continuous turnover of glucosinolates during development and not only upon tissue disruption.     

Effect of virus infection on the rhizosphere mycoflora of papaya plants

Summary Rhizosphere mycoflora of PLRV (Papaya Leaf Reduction Virus)- infected and healthy papaya plants have been investigated at the pre-flowring, flowering and post-flowering stages of plants. The fungal population per g of soil was higher in rhizosphere of diseased plants at all the three stages than that of healthy ones. The increased C/N ratio in the leaves of PLRV-infected papaya plants is responsible for the increased rhizosphere mycoflora concentration of infected plants.     

Uptake and distribution of trace elements in maturing soybean

The uptake and translocation of trace elements in maturing soybean plants cultivated on soil were studied over 360 h under diurnal conditions after the administration of a multitracer. The contents (%/g) of Co, Se, Rb, Sr, Ru, Rh, and Cs in all the leaves and stems collected from each node increased up to around 200 h after the administration of the multitracer and then decreased with time. The contents of Zn, Tc, and Re in the leaves and Zn in the stems continuously increased up to 360 h, but Tc and Re in the stems showed maximum content. This observation suggests the translocation of these elements from old leaves to growing leaves via stems. The relationship between the content (%/g) of an element in the seeds and pods, and the cultivation time varied depending on the kind of element and on the growth steps. Mathematical analyses were applied to the behavior of the elements in the soybean. The time dependence of the uptake rate (%/g/h) and distribution of elements in each part of the plant were characteristic of the element.     

Effects of Cadmium and Mixed Heavy Metals on Rice Growth in Liaoning,China

Joint effects of Cd and other heavy metals (Pb, Cu, Zn and As) on the growth and development of rice plants and the uptake of these heavy metals by rice were studied using the pot-culture method combined with chemical and statistical analyses. The results showed that the growth and development of rice plants were strongly influenced by the double-element combined pollution. There was an average decrease in the height of rice plants of 4.0–5.0 cm, and grain yield was decreased by 20.0–30.0%, compared with the control. The uptake of Cd by rice plants was promoted due to the interactions between Cd and the other heavy metals added to the soil. The Cd concentration in roots, stems/leaves and seeds increased 31.6–47.7, 16.7–61.5 and 19.6–78.6%, respectively. Due to interactions, uptake of Pb, Cu and Zn by roots and stems/leaves was inhibited, accumulation of Pb, Cu and Zn in seeds was increased, uptake of As by roots was promoted and uptake of As by stems/leaves was inhibited. In particular, the upward transporting ability of the heavy metals absorbed by rice plants was significantly increased.