Structure, development and histochemistry of embryo and endosperm in Sesbania speciosa Taub. Ex Engl.

Sesbania speciosa Taub. ex Engl. is an introduced plant cultivated in India for fibre, green manure and nutraceutical potential. The development and histochemistry of the endosperm and embryo of this plant have not been yet at all reported and the present study was carried out in an effort to bridge that gap in our knowledge. Two-micrometer sections of seeds of S. speciosa at various stages of development were cut on a rotary microtome. DNA, ribonucleic acid and insoluble polysaccharides were found to be locally localized. It was observed that the ovule of the Sesbania speciosa is campylotropous bitegmic and crassinucellate and the embryo sac is a 7-celled structure. The synergids possess PAS-positive filiform apparatus. All the cells of the mature embryo sac, before fertilization is bereft of polysaccharide grains. The embryo proper, during early embryogenesis, contains a high concentration of proteins and nucleic acids but lacks polysaccharide grains. At the dicotyledonous embryo stage, the concentration of proteins and nucleic acids declines and is followed by the synthesis of polysaccharide grains. The embryo suspensor is massive. The endosperm development is of the nuclear type. At the late globular pre-embryo stage, the micropylar 1/3 of the endosperm becomes cellular leaving the rest free-nuclear. The endosperm cytoplasm and nuclei aggregate in the micropylar region and are rich in total proteins and nucleic acids. The concentration of these metabolites, however, declines when the endosperm becomes cellular. The aleurone layer, in mature seed, is rich in proteins and nucleic acid compared to the other persisting endosperm layers

Sustainable Management Strategies and Biological Control in Apple Orchards

Sustainable horticultural practices address the global issues of food security, pest and disease management, soil health, water pollution, depletion of biodiversity, etc. with environment–friendly approaches. Increasingly, the adoption of such strategies is benefitting agricultural production including that in orchards. Even though several Integrated Pest Management (IPM), disease, and weed management strategies have been in use for the control of pests, diseases, and weeds in apple orchards, they are still not the most favored methods of control. There are various economic and acceptance concerns regarding their use, particularly in developing nations. A more sustainable system for apple orchards management, thus, should be adopted.   Here, we review various management methodologies, including the sustainable biocontrol methods, employed in the apple orchards. Reviewing these methods, we draw attention towards integrating sustainable IPM methodologies with biocontrol strategies like the use of pest-resistant cultivars, employing natural parasites and enemies of apple pests, use of agro-based pesticides, integration of technological advances that can provide real-time data to farmers and orchard scouting leading to the development of sustainable management of apple orchards. Such systems will not only reduce dependence on chemical control methods but will also minimize ecotoxicity. We also draw parallels from the biocontrol methods adopted in sustainable agri-production in other fruit orchards to suggest strategies that can be employed for sustainable apple production

Major Biological Control Strategies for Plant Pathogens

Food security has become a major concern worldwide in recent years due to ever increasing population. Providing food for the growing billions without disturbing environmental balance is incessantly required in the current scenario. In view of this, sustainable modes of agricultural practices offer better promise and hence are gaining prominence recently. Moreover, these methods have taken precedence currently over chemical-based methods of pest restriction and pathogen control. Adoption of Biological Control is one such crucial technique that is currently in the forefront. Over a period of time, various biocontrol strategies have been experimented with and some have exhibited great success and promise. This review highlights the different methods of plant-pathogen control, types of plant pathogens, their modus operandi and various biocontrol approaches employing a range of microorganisms and their byproducts. The study lays emphasis on the use of upcoming methodologies like microbiome management and engineering, phage cocktails, genetically modified biocontrol agents and microbial volatilome as available strategies to sustainable agricultural practices. More importantly, a critical analysis of the various methods enumerated in the paper indicates the need to amalgamate these techniques in order to improve the degree of biocontrol offered by them

Diversity, Succession and Seasonal Variation of Phylloplane Mycoflora of Leucaena leucocephala in Relation to Its Leaf Litter Decomposition

To address international food security concerns and sustain a growing global population, global agricultural output needs to increase by 70% by the year 2050. Current agricultural techniques to increase crop yields, specifically the application of chemicals, have resulted in a wide range of negative impacts on the environment and human health. The maintenance of good quality soil organic matter, a key concern in tropical countries such as India, requires a steady input of organic residues to maintain soil fertility. A tree with many uses, Leucaena leucocephala, has attracted much attention over the past decades. As per our literature review, no research has been conducted examining Leucaena leucocephala leaves for their fungal decomposition and their use as green manure. A study of the fungal colonization of Leucaena leucocephala leaves at various stages of decomposition was conducted to get an insight into which fungi play a critical role in the decomposition process. In total, fifty-two different species of fungi were isolated. There was an increase in the percentage of fungus occurrences as the leaves senesced and then finally decomposed. Almost all decomposition stages were characterized by a higher percentage occurrence of Deuteromycetes (75.47%) and by a lower rate of Ascomycetes (9.43%). A gradual increase of basidiomycetes such as unidentified sclerotia and Rhizoctonia solani was seen as the leaves senesced and finally decomposed. In the moist chamber, Didymium nigripes was the only Myxomycete isolated from completely decomposed leaves. In the present study, on average, there were more fungi in wet seasons than in the dry seasons