A study of the relative efficiency of mustard oil cake and urea and the effect of salinity in plankton production in indian fishponds

Augmentation of plankton production in Indian fishponds by application of manure and inorganic fertilisers was studied in laboratory experiments. The effects of the salinity of the medium were also examined.Laboratory trials were made with mustard oil cake and urea on equivalent nutrient bases in media with varying degrees of salinity (0–30 ppt at 2 ppt. intervals). It was observed that Closterium, Fragilaria, Pinnularia and Gyrosigma grew well in the higher salinity range between 24 to 30 ppt. whereas lower salinities ranging from a trace to 8 ppt. are suitable for improved production of Anabaena, Synedra, Navicula, Amphipleura, Amphora and Nitzschia. Comparatively better production of plankton was recorded with urea than with mustard oil cake.     

Sociality in the phylogenetically basal allodapine bee genus Macrogalea (Apidae: Xylocopinae): implications for social evolution in the tribe Allodapini

Recent phylogenetic studies based on DNA sequence data indicate that the tropical African bee genus Macrogalea is the sister group to the remaining extant allodapine fauna, whereas previously it was thought to be a distal group. This leads to some fundamental changes in our understanding of social evolution in the allodapines. Earlier studies suggested that Macrogalea showed only weak forms of social behaviour and these were not well characterized. However, large samples of Macrogalea zanzibarica presented here show that this species exhibits marked social behaviour. Nearly half of nests collected contained two or more adult females, with up to 10 females per nest. Brood are reared progressively and brood ages within colonies are staggered, giving rise to colonies with very mixed age structures and therefore frequent opportunities for alloparental care. Ovarian dissections indicate non‐simple forms of reproductive partitioning within colonies and most multi‐female colonies show evidence that more than one female has contributed to egg production, though reproductive episodes among colony members are frequently asynchronous. Some females show signs of much higher wing wear than their nestmates, but always show signs of previous reproduction. Reproductive division of labour appears to be temporally marked, ovarian differentiation among nestmates is linked to relative body size, but permanent worker‐like or queen‐like castes appear to be absent. This is similar to the communal, continuously brooded and multivoltine behaviour of some tropical halictine species and may be due to the aseasonal nature of brood development in tropical regions. Patterns of per capita brood production indicate large benefits to multi‐female nest occupancy, and sex allocation is strongly female biased. These findings strongly suggest that the capacity for complex social interactions and alloparental care is an ancestral trait for all of the extant allodapine lineages. Therefore comparisons among extant allodapines are unlikely to throw light on the initial origin of social behaviour, though they may uncover origins of true caste behaviour and reversals to solitary nesting. Sex ratios in Macrogalea and most other allodapine genera, spanning a broad phylogenetic and ecological range, suggest that one or more allodapine traits have provided persistent selection for female‐biased sex allocation.     

Honeydew amino acids in relation to sugars and their role in the establishment of ant-attendance hierarchy in eight species of aphids feeding on tansy (Tanacetum vulgare)

Abstract. The ratio of the concentration of honeydew total amino acids to total sugars in the honeydew of eight species of aphids, all feeding on tansy, Tanacetum vulgare (L.), was determined and correlated with honeydew production and ant‐attendance. The honeydew of the five ant‐attended aphid species [Metopeurum fuscoviride (Stroyan), Trama troglodytes (v. Hayd), Aphis vandergooti (Börner), Brachycardus cardui (L.), Aphis fabae (Scopoli)] was rich in total amino acids, ranging from 12.9 to 20.8 nmol µL^?1 compared with the unattended aphid Macrosiphoniella tanacetaria (Kalt.) with only 3 nmol µL^?1. Asparagine, glutamine, glutamic acid and serine (all nonessential amino acids) were the predominant amino acids in the honeydew of all species. The total concentration of amino acids in the phloem sap of tansy was much higher (78.7 nmol µL^?1) then in the honeydew samples, and the predominant amino acids were glutamate (34.3%) and threonine (17.7%). A somewhat unexpected result was the finding that those aphid species with the highest total amino acid concentration in the honeydew always had the highest concentration of sugars. The lowest amino acid–sugar combined value was 104–28.8 nmol µL^?1 in the non ant‐attended species M. tanacetaria, and the highest value was an average of 270–89.9 nmol µL^?1 for the three most intensely attended aphid species M. fuscoviride, A. vandergooti and T. troglodytes. There is no evidence that any single amino acid or group of amino acids in the honeydew acted as an attractant for ant‐attendance in these eight aphid species. The richness of the honeydew (rate of secretion × total concentration of sugars), along with the presence of the attractant sugar melezitose, comprised the critical factors determining the extent of ant‐attendance of the aphids feeding on T. vulgare. The high total amino acid concentration in sugar‐rich honeydews can be explained by the high flow‐through of nutrients in aphids that are particularly well attended by ants.     

Estimation of Tissue Construction Cost from Heat of Combustion and Organic Nitrogen Content

Abstract. We present a method for estimating the construction costs of plant tissues from measurements of heat of combustion, ash content, and organic nitrogen content. The method predicts glucose equivalents, the amount of glucose required to provide carbon skeletons and reductant to synthesize a quantity of organic product. Glucose equivalents have previously been calculated from the elemental composition of tissue. We define construction cost as the amount of glucose required to provide carbon skeletons, reductant and ATP for synthesizing the organic compounds in a tissue via standard biochemical pathways. The fraction of the total construction cost of a compound or tissue (excluding costs of transporting compounds) that is reflected in its glucose equivalents is the biosynthetic efficiency ( E _B). This quantity varies between 0.84 and 0.95 for tissues with a wide range of compositions. Using the new method, total construction cost can be estimated to ± 6% of the value obtained from biochemical pathway analysis.
Construction costs of leaves of three chaparral species were estimated using the proposed method and compared to previously published values, derived using different methods. Agreement among methods was generally good. Differences were probably due to a combination of inaccuracy in the estimated biosynthetic efficiency and technical difficulties with biochemical analysis, one of the older methods of determining construction cost.     

The relationship between respiration and temperature in leaves of the arctic plant Saxifraga cernua

Abstract Saxifraga cernua, a perennial herb distributed throughout the arctic and subarctic regions, shows high levels of dark respiration. The amount of respiration exhibited by leaves and whole plants at any temperature is influenced by the pretreatment temperature. Plants grown at 10°C typically show higher dark respiration rates than plants grown at 20°C. The levels of alternative-pathway respiration (or cyanide-insensitive respiration) in leaves of S. cernua grown at high and low temperatures were assessed by treating leaf discs with 0.25 mol m^?3 salicylhydroxamic acid during measurements of oxygen consumption. Alternative pathway respiration accounted for up to 75% of the total respiration. Tissues from 20°C-grown plants yielded a Q₁₀ of 3.37 for normal respiration, and of 0.97 for alternative-pathway respiration. Tissues from 10°C-grown plants yielded a Q₁₀ of 2.55 for normal respiration, and of 0.79 for alternative-pathway respiration. The alternative pathway does not appear to be as temperature sensitive as the normal cytochrome pathway. A simple energy model was used to predict the temperature gain expected from these high rates of alternative-pathway respiration. The model shows that less than 0.02°C can be gained by leaves experiencing these high respiration rates.     

cDNA and protein sequence of a major pea seed albumin (PA 2 : Mr≈26 000)

Summary Pea albumin 2 (PA2:M_r26000) is a major component of the albumin fraction derived from aqueous salt extracts of pea seed. Sodium dodecylsulfate-polyacrylamide gel electrophoresis and chromatography on DEAE-Sephacel resolve PA2 into two closely related components (PA2a and PA2b). A cDNA clone coding for one of these components has been sequenced and the deduced amino acid sequence compared with partial, chemically-determined sequences for cyanogen bromide peptides from both PA2 components. Complete amino acid sequences were obtained for the C-terminal peptides. The PA2 molecule of 230 amino acids contains four imperfect repeat sequences each of approximately 57 amino acids in length.The combined sequence data, together with a comparison of PA2-related polypeptides produced in vitro and in vivo, indicate that PA2 is synthesized without a signal sequence and does not undergo significant post-translational modification. Although both forms of PA2 contain Asn-X-Thr consensus sequences, neither form is glycosylated. Accumulation of PA2 contributes approximately 11% of the sulfur-amino acids in pea seeds (cysteine plus methionine equals 2.6 residues percent). Suppression of levels of PA2 polypeptides and their mRNAs in developing seeds of sulfur-deficient plants is less marked than that for legumin, in spite of the lower content of sulfur-amino acids in legumin.     

Effects of simulated feeding by snow geese on Scirpus americanus rhizomes

Summary We simulated the feeding of Greater Snow Geese (Chen caerulescens atlantica) on the rhizomes of three-square bulrush (Scirpus americanus) in a tidal marsh along the St. Lawrence River estuary in Québec. During the spring staging period, aboveground biomass is unavailable and geese feed solely on rhizomes and overwintering buds. An experiment was designed to test the effect of three factors on subsequent growth of Scirpus: the intensity of removal (3 to 77% removal of belowground biomass), the number of bites (1, 2 or 3 sections removed) and the number of adventitious buds removed (1, 2 or 3). Rhizomes were dug out in May, treated and transplanted into 85-1 basins sunk in the marsh and filled with marsh soil freed of all plant material. Growth was observed weekly until the end of the growing season in August. Shoots and rhizomes were then collected, dried and weighed to obtain biomass estimates. The net above- and belowground production of Scirpus was inversely related to the initial rhizome biomass removed. At a high level of removal (>35%), the cumulative number of shoots was significantly reduced as early as two weeks after transplantation. The relative reduction in production of the treated rhizomes compared to the control plants was also related to the intensity of removal. An increased number of bites reduced production and the removal of an increased number of adventitious buds further amplified the effect of removal on rhizome production. These experimental results show that even low intensity of feeding by Snow Geese can reduce the production of Scirpus marshes.     

Ultrastructure ofCatharanthus roseus cells culturedin vitro and exposed to conditions for alkaloid accumulation

Summary Periwinkle (Catharanthus roseus) cells cultured in 1-B 5 medium display the ultrastructure of parenchyma cells. The parenchyma character remained unchanged when cells were exposed to any one of three different conditions effecting alkaloid accumulation. Transfer of cells to alkaloid production medium for 2 weeks (condition 1) accorded two special features,i.e., unusually big lipid droplets in the cytoplasm and, upon fixation, one or several electron-dense droplets of spongy precipitate in vacuoles. Among hormone-autotrophic cultures (condition 2) some cells showed a fine electron-dense vacuolar precipitate. Addition ofPhythium homogenate (fungal elicitor) to cells cultured in 1-B 5-medium for 10 days (condition 3), cells showed a frequent appearance of singular big lipid droplets in the cytoplasm, whereas vacuoles remained devoid of precipitate. The appearance of big lipid droplets and of vacuolar precipitate is interpreted as progressing cytodifferentiation, but is coincidental with alkaloid accumulation.NRCC no. 24524.     

不同海拔地区种植的水稻地上部干物质的生产和分配

根据1983—1985年“高原水稻高产栽培的生理生态规律研究”中低热的元江(海拔400米左右)、温凉的昆明(约1900米)和冷凉的丽江(约2400米)的资料,以六个处理、十八个小区、三年总平均值,比较了不同海拔地区种植的水稻中地上部干物质生产和分配的总趋势。主要结果如下: 1.全生育期总的干物质生产量以温凉地区最高,低热地区居中,冷凉地区最低。 2.抽穗前干物质生产速率和齐穗期干物重占黄熟期干物重的比例随海拔降低而增加;抽穗期至黄熟期干物质生产速率,以温凉地区最高,低热地区居中,冷凉地区最低,但低热地区低于前期,高海拔地区高于前期,不过冷凉的丽江增加的更多。 3.抽穗前(旗叶完全展开后)叶干重占当时植株总干重的比例,随海拔升高而降低。 4.抽穗期至黄熟期的次库(茎 叶鞘)干重的改变,不同海拔地区种植的水稻表现不同:低热地区减重,温凉地区稍增,冷凉地区明显增加。 5.与高海拔地区种植的水稻相比,在黄熟期低海拔地区的有较高的穗重/总重和穗增重/总增重的比例。另外低海拔地区的穗增重超过总增重。结实率和谷/草比例均随海拔增高而减低。