A comparative study of the leaves of Cat hay a argyrophylla Chun & Kuang and three species of Keteleeria Carrière

Details of the cuticular, epidermal and anatomical features of the leaves of Cathaya argyrophylla Chun & Kuang, are described and compared with those of three species of Keteleeria (K. davidiana (Bertrand) Beissner, K. fortunei (Murray) Carriere, and K. chien-peii Flous). The study supports the creation of Cathaya Chun & Kuang as a new genus of the Pinaceae.     

Induction of Cell Division in Leaf Cells of Coconut Palm by Alteration of pH and its Correlation with Glyoxalase-I Activity

Cell division in suspension cultures obtained from leaf cellsof coconut was influenced by pH of the culture media. A 3-foldincrease in cell number was obtained at pH 7.0 compared to suspensionsgrowing at pH 5.0. The pH of both cells and media changed after48 h of growth. Internal cell pH showed a significant increasewhen cultures were grown at pH 7.0 and 8.0 and increased onlyslightly at pH 5.0 and 6.0. Glyoxalase-I activity of cells insuspension culture was found to be pH-depcndent, showing maximumactivity at pH 7.0. Glutathione, a co-enzyme for the substratemethylglyoxaJ for glyoxalase-I, produced a 2-fold increase incell number at a concentration of 5 x 10^–3 mol dm ^–3.The polyamine, spermidine, promoted cell division maximallyat a concentration of 10^–6 mol dm^–3. Methylglyoxal-bis(guanylhydrazone), an inhibitor of spermidine biosynthesis,strongly inhibited cell division giving maximum inhibition ata concentration of 3 x 10^–6 mol dm ^–3. These resultsindicate a positive correlation between cell division and glyoxalase-Iactivity. Key words: Cocos nucifera, glyoxalase-I, pH, spermidine     

A Rapid Method for the Determination of the Leaf Area of Oxalis corniculata L. and Tephrosia purpurea (Linn.) pers.

A rapid simple method has been described for the determinationof leaf area of Oxalis corniculata L. (Oxalidaceae) and Tephrosiapurpurea (Linn.) pers. (Leguminoseae) by evaluating area = a²x0.866and a²x0.335 respectively for the two plants, where a representsa single linear measurement. The relation has been derived afterintegrating the equation of the curve r² = a² cos 2 coveringthe area of each leaflet. Areas of a large number of leaflets have been determined withthe help of two methods (1) Planimeter method, (2) Evaluationmethod. The significance of the difference between the two valuesfor a particular leaf has been statistically examined and itappears that the former method can be replaced by the latterin the case of these plants.     

Heat Tolerance and Assimilate Transport in Different Potato Genotypes

Six potato genotypes with different degrees of heat tolerancewere grown in pots at 38/25 'b0C maximum/minimum temperatureat 14 h daylength under natural light glasshouse conditions.Prior to sampling, the plants were given a 14 h dark period.Photosynthesis was measured at 28 'b0C and at a saturating lightintensity of more than 1200 µEm^-2 s^-1. During the optimumphotosynthetic period (09.00–12.30 h), the leaves of heat-tolerantpotato genotypes (DTO-28, Norchip, and Desiree) had 4–5times more soluble sugars (mainly sucrose) and higher sucrose-phosphatesynthase activity than the leaves of the heat-susceptible genotypes(Kufri Jyoti, Kufri Chandramukhi, and Kufri Muthu). However,starch accumulation in leaves of susceptible genotypes was abouttwice that in tolerant genotypes. All susceptible genotypesshowed a low rate of assimilate transport from leaves and ahigher shoot/root ratio which indicated that the shoot remainedthe predominant sink for photosynthate. Activities of amylaseand invertase in leaves were also higher in susceptible genotypes.It is suggested that the poor yield of heat-susceptible genotypesat high temperature and long day conditions is related to insufficientavailability of the transportable sugar, sucrose. Key words: Solarium tuberosum, carbon partitioning, heat stress     

Differential profiling of selected defence‐related genes induced on challenge with Alternaria brassicicola in resistant white mustard and their comparative expression pattern in susceptible India mustard

The lack of availability of sources of resistance against Alternaria brassicicola within the family Brassicaceae has made oilseed mustard plants a target for one of the most damaging and widespread fungal diseases, Alternaria black spot. Of the other non‐host‐resistant/tolerant plants, Sinapis alba, white mustard, is considered to be the most important apart from Arabidopsis. To understand the defence response of S. alba upon incompatible interaction with this pathogen, a functional genomic approach using cDNA amplified fragment length polymorphism was performed. The highly reproducible bands, found to be either more amplified or uniquely present in infected S. alba plants compared with non‐infected plants, were further subjected to comparative reverse Northern analysis in the incompatible white mustard (S. alba) and compatible India mustard (Brassica juncea L.) plants. The suppression of 46% of the genes in the compatible background indicates the possibility of effective and specific recognition of Alternaria in S. alba. Analysis of the 118 genes up‐regulated specifically in infected S. alba compared with B. juncea showed that 98 genes have similarity to proteins such as receptor‐like protein kinase genes, genes involved with calcium‐mediated signalling and salicylic acid‐dependent genes as well as other genes of known function in Arabidopsis. The apparent expression profile data were further confirmed for selected genes by quantitative real‐time polymerase chain reaction analysis. Classification of these genes on the basis of their induction pattern in Arabidopsis indicates that the expression profile of several of these genes was distinct in S. alba compared with B. juncea.     

黄钩尺蛾在四个茶树无性系品种上的生长和存活(英文)

在实验室条件下, 对食叶害虫黄钩尺蛾Hyposidra infixaria Walker在4个茶树Camellia sinensis无性系品种（TV1, TV9, TV25和Teen ali 17）上的生长和存活进行了研究, 以确定其最适合寄生的茶树无性系品种。结果表明： 在TV25上的黄钩尺蛾幼虫期 (15.78 d)比在TV1 (18.14 d), TV9 (18.00 d)和Teen ali 17 (17.00 d)上显著缩短。黄钩尺蛾按幼期龄数分为5龄型和6龄型两类。6龄型幼虫在TV25上的发生率显著高于其在其他3个无性系品种上的发生率。在TV25上黄钩尺蛾幼虫和蛹的体重也显著高于在其他3个无性系品种上的。同样地, 以TV25为食的黄钩尺蛾未成熟阶段的存活率显著高于其以其他3个无性系品种为食的存活率。基于生长参数和存活率, 我们发现TV25是黄钩尺蛾最适合寄生的茶树无性系品种。     

Detection of cross reactive antigens between Pestalotiopsis theae and tea leaves and their cellular location

Among the 12 varieties of tea tested against three isolates of Pestalotiopsis theae, causal agent of grey blight disease, Teen Ali-17/1/54 and TV-23 were found to be highly susceptible while CP-1 and TV-26 were resistant under identical conditions. Leaf antigens were prepared from all the tea varieties, three isolates of P. theae and a non-pathogen of tea (Bipolaris tetramera). Polyclonal antisera were raised against mycelial suspensions of P. theae (isolate Pt-2) and leaf antigens of Teen Ali-17/1/54 and CP-1. These were compared an immunodiffusion test and enzyme-linked immunosorbent assay to detect cross reactive antigens (CRA) shared the host and the parasite. CRA were found among the susceptible varieties and isolates of P. theae (Pt-1, 2 and 3). Such antigens were not detected between isolates of P. theae and resistant varieties, B. tetramera and tea varieties or isolates of P. theae. Indirect staining of antibodies using fluorescein isothiocyanate (FITC) indicated that in cross sections of tea leaves, the CRA was concentrated in the epidermal cells and mesophyll tissues. CRA was present in the young hyphal tips of the mycelia and on the setulae and appendages of the conidia of P. theae.     

Effect of Non-auxin Chemicals on Translocation of Auxins in Cuttings of Phaseolus vulgaris (L.)

Indole, -naphthol, pyrogallol, coumarin, and salicylic acidinteracted with the auxins, IAA (indol-3yl-acetic acid), NAA(naphth-lyl-acetic acid), and 2, 4-D (2, 4-dichlorophenoxyaceticacid), supplied to the basal ends of cuttings of Phaseolus vulgaris(L.), giving synergistic or antagonistic effects in root formation.Antagonism in rooting was always associated with increased accumulationof radiocarbon from carboxyl-¹⁴C-labelled auxins in the topsof the cuttings. Distribution of auxin over a greater lengthof the cutting was accompanied by a reduction in root formation.The chemicals which synergized auxin-induced root formationdid not promote accumulation of radiocarbon of the exogenouslyapplied labelled auxins in the upper parts of the cuttings.