Systematics, Bionomics and Seed Production of Macrobrachium spp. of the Vembanad Lake

School of Industrial Fisheries, Cochin University of Science and Technology

Effects of the Piscicides, Mahua Oil Cake and Croton Seed on the Prawn Culture System

Department of Marine Biology, Microbiology and Biochemistry

Studies on seed pathology and seedling diseases of some important indigenous tree species of kerala

In forestry, availability of healthy seeds is an important factor in raising planting stock. Initial seed health and storage conditions are the major factors governing the germinability of seeds. Like seeds of agricultural and horticultural crops, forest tree seeds are also liable to be affected by micro-organisms during storage, which affects the germination, and reduces the viability. Further introduction of seed-borne diseases into newly sown crops/areas on account of using unhealthy seeds is also not ruled out. Availability of healthy stock of seedlings is intrinsic for raising plantations and to meet this requirement elimination of nursery diseases by appropriate chemicals is of prime imortance. As exotic tree species may become susceptible to various native pathogens, it is generally considered better to select indigenous tree species for large scale plantations as they are well adapted to local environment. However, before taking up large scale afforestation progranme involving any indigenous tree species, it is essential to have knowledge about seed disorders and seedling diseases and their management. with a View to select appropriate tree species with fewer seed disorders and seedling disease problems for use in further plantation programme, four indigenous tree species such as Albizia odoratissima (L.f) Benth., Lagerstroemia microcazpa Wt., Pterocazpus marsupiwn Roxb. and Xylia xylocarpa (Roxb.) Taub. were evaluated to meet the above parameters

Effects Of The Piscicides, Mahua Oil Cake And Croton Seed On The Prawn Culture System

The present research programme envisages a comparative study of the effects of two piscicides of plant origin, viz., mahua oil cake, a derivative from the plant fig Iatifolia and croton seed, a product from the plant Croton tiglium. Although some reports on the effects of mahua oil cake and croton seed on fresh water pond culture systems are available, information on their effect on brackishwater culture systems are rather scanty This was the guiding principle for launching the present study It is hoped that the findings will enable aquaculturists to make use of the piscicides in a more rational and efficient way, and will go a long way towards realising the maximum return liom culture systems without hampering the environment. The thesis is presented in seven chapters such as Introduction, Review of literature, Materials and Methods, Results, Discussion, Summary and Bibliography

Ecophysiology of seed dormancy and salt tolerance of Grewia tenax (Forssk.) Fiori and Ziziphus spina-christi (L.) Willd.

Higher Education Commission (HEC) of Pakistan and German Academic Exchange Service (DAAD)

The role of NGO in informal seed production and dissemination: The case of eastern Ethiopia

Seed is the basic input to crop production. Farmer-based seed production as an alternative agricultural technology transfer is increasingly given especial attention in developing countries where food insecurity is critical. This paper aims to assess the seed production and dissemination strategy among smallholder farmers in eastern Ethiopia that has been introduced by Hararghe Catholic Secretariat (a Non-GovernmentalOrganization). A survey of 160 households in four administrative districts and focus group discussions were used to collect data. While narratives helped understand the process, logistic regressionwas used to identify determinants of land allocation to seed production. Results indicate the crucial role of informal networks and social capital as facilitators of access to production inputs, information and knowledge. The informal seed supply system initiated by the NGO has a huge potential to benefit smallholder farmers by improving their access to higher-yielding varieties of various crops, thereby contributing to an increase in their wellbeing. However, the traditional practice of seed exchange, influenced by social relations, will remain uneconomical to seed producers. Thus, the paper suggests that this potential can be further exploited if some preconditions such as establishment of seed banks, investment in human capital, removal of the underlying constraints and creation of reliable seed markets are given emphasis.

Virtualization of seed research: perhaps a continuity model.

The research nurseries serve as a initiative designed for the purpose of contribute to the breakdown of seizure paradigms of knowledge, supported by a theoretical model of discernment that exceed the traditional method of learning in the classroom, to transcend critical insights into transforming the environment under an autonomous space to provide tools essentially scientific, but with ethical criterion and social commitment. Such a conception, however, could be perceived as talkative, and even metaphorical, at the contrast of reality purely versatile in which the neophyte not only tries to get enough of the fruit of knowledge, but also requires that appropriate strategies are put forward to achieve seizure. Then arises, from the formative entelechy the use of technological tools based on virtual learning environments, in order to enhance motivation as an alternative against the blurring of perspectives and the emerging business in some types of nurseries, stranded attitude, that sometimes not far from the master model.

Patterns of pollen and seed dispersal in a small, fragmented population of the wind-pollinated tree Araucaria angustifolia in southern Brazil

Paternity analysis based on eight microsatellite loci was used to investigate pollen and seed dispersal patterns of the dioecious wind- pollinated tree, Araucaria angustifolia. The study sites were a 5.4 ha isolated forest fragment and a small tree group situated 1.7 km away, located in Paran alpha State, Brazil. In the forest fragment, 121 males, 99 females, 66 seedlings and 92 juveniles were mapped and genotyped, together with 210 seeds. In the tree group, nine male and two female adults were mapped and genotyped, together with 20 seeds. Paternity analysis within the forest fragment indicated that at least 4% of the seeds, 3% of the seedlings and 7% of the juveniles were fertilized by pollen from trees in the adjacent group, and 6% of the seeds were fertilized by pollen from trees outside these stands. The average pollination distance within the forest fragment was 83 m; when the tree group was included the pollination distance was 2006m. The average number of effective pollen donors was estimated as 12.6. Mother- trees within the fragment could be assigned to all seedlings and juveniles, suggesting an absence of seed immigration. The distance of seedlings and juveniles from their assigned mother- trees ranged from 0.35 to 291m ( with an average of 83m). Significant spatial genetic structure among adult trees, seedlings, and juveniles was detected up to 50m, indicating seed dispersal over a short distance. The effective pollination neighborhood ranged from 0.4 to 3.3 ha. The results suggest that seed dispersal is restricted but that there is longdistance pollen dispersal between the forest fragment and the tree group; thus, the two stands of trees are not isolated.

Influence of sodium chloride on seed germination and seedling root growth of cotton (Gossypium hirsutum L.)

Response of cotton (Gossypium hirsutum L. cv. NIAB-78) to salinity, in terms of seed germination, seedling root growth and root Na+ and K+ content was determined in a laboratory experiment. Cotton seeds were exposed to increasing salinity levels using germination water with Sodium chloride concentrations of 0, 50, 100, 150 and 200 mM, to provide different degrees of salt stress. Germinated seeds were counted and roots were harvested at 24, 48, 72 and 96 h after the start of the experiment. It appeared that seed germination was only slightly affected by an increase in salinity (in most cases the differences between treatment were non-significant), whereas root length, root growth rate, root fresh and dry weights were severely affected, generally highly significant differences in these variables were found for comparisons involving most combinations of salinity levels, in particular with increased incubation period. K+ contents decreased with increasing salinity levels, although differences in K+ content were only significant when comparing the control and the 4 salinity levels. Na+ content of the roots increased with increasing levels of NaCl in the germination water, suggesting an exchange of K+ for Na+. The ratio K+/Na+ strongly decreased with rising levels of salinity from around 4.5 for the control to similar to 1 at 200 mM NaCl.

Effects of patch size and density on flower visitation and seed set of wild plants: a pan-European approach

1. Habitat fragmentation can affect pollinator and plant population structure in terms of species composition, abundance, area covered and density of flowering plants. This, in turn, may affect pollinator visitation frequency, pollen deposition, seed set and plant fitness. 2. A reduction in the quantity of flower visits can be coupled with a reduction in the quality of pollination service and hence the plants’ overall reproductive success and long-term survival. Understanding the relationship between plant population size and⁄ or isolation and pollination limitation is of fundamental importance for plant conservation. 3. Weexamined flower visitation and seed set of 10 different plant species fromfive European countries to investigate the general effects of plant populations size and density, both within (patch level) and between populations (population level), on seed set and pollination limitation. 4. Wefound evidence that the effects of area and density of flowering plant assemblages were generally more pronounced at the patch level than at the population level. We also found that patch and population level together influenced flower visitation and seed set, and the latter increased with increasing patch area and density, but this effect was only apparent in small populations. 5. Synthesis. By using an extensive pan-European data set on flower visitation and seed set we have identified a general pattern in the interplay between the attractiveness of flowering plant patches for pollinators and density dependence of flower visitation, and also a strong plant species-specific response to habitat fragmentation effects. This can guide efforts to conserve plant–pollinator interactions, ecosystem functioning and plant fitness in fragmented habitats.

Global transcript analysis of rice leaf and seed using SAGE technology.

We have compiled two comprehensive gene expression profiles from mature leaf and immature seed tissue of rice (Oryza sativa ssp. japonica cultivar Nipponbare) using Serial Analysis of Gene Expression (SAGE) technology. Analysis revealed a total of 50 519 SAGE tags, corresponding to 15 131 unique transcripts. Of these, the large majority (approximately 70%) occur only once in both libraries. Unexpectedly, the most abundant transcript (approximately 3% of the total) in the leaf library was derived from a type 3 metallothionein gene. The overall frequency profiles of the abundant tag species from both tissues differ greatly and reveal seed tissue as exhibiting a non-typical pattern of gene expression characterized by an over abundance of a small number of transcripts coding for storage proteins. A high proportion ( approximately 80%) of the abundant tags (> or = 9) matched entries in our reference rice EST database, with many fewer matches for low abundant tags. Singleton transcripts that are common to both tissues were collated to generate a summary of low abundant transcripts that are expressed constitutively in rice tissues. Finally and most surprisingly, a significant number of tags were found to code for antisense transcripts, a finding that suggests a novel mechanism of gene regulation, and may have implications for the use of antisense constructs in transgenic technology.

Microbial relatives of the seed storage proteins of higher plants: conservation of structure and diversification of function during evolution of the cupin superfamily.

This review summarizes the recent discovery of the cupin superfamily (from the Latin term "cupa," a small barrel) of functionally diverse proteins that initially were limited to several higher plant proteins such as seed storage proteins, germin (an oxalate oxidase), germin-like proteins, and auxin-binding protein. Knowledge of the three-dimensional structure of two vicilins, seed proteins with a characteristic beta-barrel core, led to the identification of a small number of conserved residues and thence to the discovery of several microbial proteins which share these key amino acids. In particular, there is a highly conserved pattern of two histidine-containing motifs with a varied intermotif spacing. This cupin signature is found as a central component of many microbial proteins including certain types of phosphomannose isomerase, polyketide synthase, epimerase, and dioxygenase. In addition, the signature has been identified within the N-terminal effector domain in a subgroup of bacterial AraC transcription factors. As well as these single-domain cupins, this survey has identified other classes of two-domain bicupins including bacterial gentisate 1, 2-dioxygenases and 1-hydroxy-2-naphthoate dioxygenases, fungal oxalate decarboxylases, and legume sucrose-binding proteins. Cupin evolution is discussed from the perspective of the structure-function relationships, using data from the genomes of several prokaryotes, especially Bacillus subtilis. Many of these functions involve aspects of sugar metabolism and cell wall synthesis and are concerned with responses to abiotic stress such as heat, desiccation, or starvation. Particular emphasis is also given to the oxalate-degrading enzymes from microbes, their biological significance, and their value in a range of medical and other applications.

Microbial relatives of seed storage proteins: conservation of motifs in a functionally diverse superfamily of enzymes

Plant storage proteins comprise a major part of the human diet. Sequence analysis has revealed that these proteins probably share a common ancestor with a fungal oxalate decarboxylase and/or related bacterial genes. Additionally, all these proteins share a central core sequence with several other functionally diverse enzymes and binding proteins, many of which are associated with synthesis of the extracellular matrix during sporulation/encystment. A possible prokaryotic relative of this sequence is a bacterial protein (SASP) known to bind to DNA and thereby protect spores from extreme environmental conditions. This ability to maintain cell viability during periods of dehydration in spores and seeds may relate to absolute conservation of residues involved in structure determination.