Richard E. Litz

Bio: Richard E. Litz is an academic researcher from University of Florida. The author has contributed to research in topics: Somatic embryogenesis & Callus. The author has an hindex of 30, co-authored 106 publications receiving 3029 citations.

The Mango: Botany, Production and Uses

Abstract: 1. Botany and Importance S K Mukherjee (deceased) and R E Litz 2. Taxonomy and Systematics J M Bompard 3. Important Mango Cultivars and Their Descriptors R J Knight, Jr., R J Campbell and I Maguire 4. Breeding and Genetics C P A Iyer and R J Schnell 5. Reproductive Physiology T L Davenport 6. Ecophysiology B Schaffer, L Urban, P Lu and A W Whiley 7. Fruit Diseases D Prusky, I Kobiler, I Miyara and N Alkan 8. Foliar, Floral and Soilborne Diseases R C Ploetz and S Freeman 9. Physiological Disorders V Galan Sauco 10. Pests J E Pena, M Aluja and M Wysoki 11. Crop Production: Propagation S Ram (deceased) and R E Litz 12. Crop Production: Mineral Nutrition I S E Bally 13. Crop Production: Management J H Crane, S Salazar-Garcia, T-S Lin, A C de Queiroz Pinto and Z-H Shu 14. Postharvest Physiology J K Brecht and E M Yahia 15. Postharvest Technology and Quarantine Treatments G I Johnson and 16. P J Hofman 17. World Mango Trade and the Economics of Mango Production E A Evans and O J Mendoza 18. Fruit Processing L C Raymundo, M T Ombico and T M de Villa 19. Biotechnology R E Litz, M A Gomez Lim and U Lavi.

Biotechnology of perennial fruit crops.

Abstract: Part 1 Biotechnologies: organogenesis and somatic embryogenesis, Richard E. Litz and Dennis J. Gray somaclonal variation, Freddi A. Hammerschlag haploidy, Yong Xiang Zhang and Yves Lespinasse protoplasts, Sergio J. Ochatt, et al molecular markers, Gloria A. Moore and Richard E. Durham transformation, Abhaya M. Dandekar in vitro conservation, Lyndsey A. Withers. Part 2 Fruit crops: apple, Schuyler Safi Korban and Houqi Chen grape, Dennis J. Gray and Carole P. Meredith pear, Elisabeth Chevreau and Robert M. Skirvin stone fruits, Ralph Scorza and Freddi A. Hammerschlag temperate small fruits, R.J. McNicol and J. Graham avocado, F. Pliego-Alfaro and B.O. Bergh citrus, Frederick G. Gmitter, et al olive, E. Rugine and S. Lavee coconut and date palm, Abdellatif K. Benbadis coffee, M.R. Sondahl and J.A. Lauritis guava and jackfruit, Vijai S. Jaiswal and Muhammed N. Amin mango, Helena Mathews and Richard E. Litz musa (bananas and plantains), F.J. Novak papaya, Richard M. Manshardt tropical and subtropicial small fruits, Miguel Jordan & Claudia Botti.

Biotechnology of Fruit and Nut Crops

Abstract: Kiwifruit Cashew Soursop Coconut Papaya Cranberry Chestnut Pecan Avocado Fig Banana Guava Olive Carambola Passionfruit Strawberry Citrus Grape Mango Pistachio Atemoya Oil palm Date palm Pineapple Mangosteen Blueberry Walnut Jackfuit Prunus species Rubus species Pear Quince Apple Cacao Litchi Longan

High-efficiency somatic embryogenesis and plant regeneration from suspension cultures of grapevine

Abstract: Embryogenic suspensions of grapevine (Vitis vinifera L.) were initiated from somatic embryos of `Thompson Seedless' and `Chardonnay'. Suspension cultures consisted of proembryonic masses (PEM) that proliferated without differentiation in a medium containing 2,4-dichlorophenoxyacetic acid (2,4-D). `Chardonnay' somatic embryos developed fully from PEMs following subculture in medium without 2,4-D; however, somatic embryo development did not advance beyond the heart stage in `Thompson Seedless' suspension cultures. Highly synchronized development of somatic embryos was obtained by inoculating <960-μm PEMs into liquid medium without 2,4-D. Somatic embryos were also produced in large numbers from suspension-derived PEMs of both cultivars on semisolid medium lacking 2,4-D. Somatic embryos matured and regenerated into plants in MS basal medium containing 3% sucrose. Using this method more than 60% of the somatic embryos regenerated plants. More than 90% of the regenerated plants were successfully transferred to the greenhouse.

Fruit Ripening Phenomena–An Overview

Abstract: Fruits constitute a commercially important and nutritionally indispensable food commodity. Being a part of a balanced diet, fruits play a vital role in human nutrition by supplying the necessary growth regulating factors essential for maintaining normal health. Fruits are widely distributed in nature. One of the limiting factors that influence their economic value is the relatively short ripening period and reduced post-harvest life. Fruit ripening is a highly coordinated, genetically programmed, and an irreversible phenomenon involving a series of physiological, biochemical, and organoleptic changes, that finally leads to the development of a soft edible ripe fruit with desirable quality attributes. Excessive textural softening during ripening leads to adverse effects/spoilage upon storage. Carbohydrates play a major role in the ripening process, by way of depolymerization leading to decreased molecular size with concomitant increase in the levels of ripening inducing specific enzymes, whose target differ from fruit to fruit. The major classes of cell wall polysaccharides that undergo modifications during ripening are starch, pectins, cellulose, and hemicelluloses. Pectins are the common and major components of primary cell wall and middle lamella, contributing to the texture and quality of fruits. Their degradation during ripening seems to be responsible for tissue softening of a number of fruits. Structurally pectins are a diverse group of heteropolysaccharides containing partially methylated D-galacturonic acid residues with side chain appendages of several neutral polysaccharides. The degree of polymerization/esterification and the proportion of neutral sugar residues/side chains are the principal factors contributing to their (micro-) heterogeneity. Pectin degrading enzymes such as polygalacturonase, pectin methyl esterase, lyase, and rhamnogalacturonase are the most implicated in fruit-tissue softening. Recent advances in molecular biology have provided a better understanding of the biochemistry of fruit ripening as well as providing a hand for genetic manipulation of the entire ripening process. It is desirable that significant breakthroughs in such related areas will come forth in the near future, leading to considerable societal benefits.

Thidiazuron : A potent regulator of in vitro plant morphogenesis

Abstract: TDZ (N-phenyl-N’-1,2,3-thidiazol-5-ylurea) is a substituted phenylurea compound which was developed for mechanized harvesting of cotton bolls and has now emerged as a highly efficacious bioregulant of morphogenesis in the tissue culture of many plant species. Application of TDZ induces a diverse array of cultural responses ranging from induction of callus to formation of somatic embryos. TDZ exhibits the unique property of mimicking both auxin and cytokinin effects on growth and differentiation of cultured explants, although structurally it is different from either auxins or purine-based cytokinins. A number of physiological and biochemical events in cells are likely to be influenced by TDZ, but these may or may not be directly related to the induction of morphogenic responses, and hence, the mode of action of TDZ is unknown. However, the recent approaches applied to study the morphogenic events initiated by TDZ are clearly beginning to reveal the details of a variety of underlying mechanisms. Various reports indicate that TDZ may act through modulation of the endogenous plant growth regulators, either directly or as a result of induced stress. The other possibilities include the modification in cell membranes, energy levels, nutrient uptake, or nutrient assimilation. In this review, several of these possiblities are presented and discussed in light of recently published studies on characterization of TDZ-induced morphogenic effects.

Tissue culture-derived variation in crop improvement

Abstract: Tissue culture generates a wide range of genetic variation in plant species which can be incorporated in plant breeding programmes By in vitro selection, mutants with useful agronomic traits, eg salt or drought tolerance or disease resistance, can be isolated in a short duration The successful use of somaclonal variation is very much dependent on its genetic stability in the subsequent generations for which molecular markers such as RAPDs, AFLPs, SSRs and others can be helpful The potential of somaclonal variation has yet to be fully exploited by breeders, even though a few cultivars have been developed in crops such as Brassica juncea, rice and others

Involvement of plant hormones and plant growth regulators on in vitro somatic embryogenesis

Abstract: In spite of the importance attained by somatic embryogenesis and of the many studies that have been conducted on this developmental process, there are still many aspects that are not fully understood. Among those features, the involvement of plant hormones and plant growth regulators on deTermining the conversion of somatic onto embryogenic tissues, and on allowing progression and maturation of somatic embryos, are far away from being completely comprehended. Part of these difficulties relies on the frequent appearance of contradictory results when studying the effect of a particular stimulus over a specific stage in somatic embryogenesis. Recent progress achieved on understanding the interaction between exogenously added plant growth regulators over the concentration of endogenous hormones, together with the involvement of sensitivity of the tissues to particular hormone groups, might help clarifying the occurrence of divergent patterns in somatic embryogenesis, and in tissue culture in general. The aspects described above, emphasizing on the effect of the concentration of plant hormones and of the addition of plant growth regulators during the different phases of somatic embryogenesis, will be reviewed in this paper. Citations will be limited to review articles as much as possible and to individual articles only in those cases in which very specific or recent information is presented.