The mango Mangifera indica L. is considered to be one of the most important fruit crops of the wo... more The mango Mangifera indica L. is considered to be one of the most important fruit crops of the world (Fig. 1). Its annual production is exceeded only by Musa (bananas and plantains), citrus, grapes and apples (FAO Production Yearbook, 1990). Currently, it is the most important fruit crop of Asia. Mango is in the Anacardiaceae family, which includes several other tropical and subtropical tree species of economic importance, e.g., cashew Anacardium occidentale, pistachio Pistachia vera, and several Spondias species, including S. cytherea, S. mombin and S. purpurea. The center of diversity for the genus Mangifera is in southeast Asia, with the greatest number of species being found on the island of Borneo. According to Mukherjee (1985), there are 39 currently recognized Mangifera species. The mango is the most widely cultivated species within the genus, and has a natural distribution throughout outheast Asia. It is found in forests as far west as the Indo-Burman region (Assam). There appear to be two distinct geographical races of the species: a polyembryonic race that occurs in the tropical rainforest of southeast Asia and a monoembryonic race that is associated with India. Some taxonomists have suggested that the mango originated in India, because of the ancient association between Indian culture and religion with this fruit. It has also been noted that the word for mango used throughout Asia is derived from the Tamil “maanga”.
Summary Embryogenic callus was induced from leaflets of new vegetative flushes of mature longan (... more Summary Embryogenic callus was induced from leaflets of new vegetative flushes of mature longan (Euphoria longan Stend.) trees. Induction of embryogenic competency was dependent on the presence of auxin (2,4-D) and cytokinin (kinetin) in the growth medium (B5 with 400mg liter-1 glutamine, 60g liter-1 sucrose, 200 mg liter-1 casein hydrolysate and 1.7g liter-1 Gelrite). The optimum range of phytohormone concentrations was 0.25 - 2.0 mg liter-1 of kinetin and 2,4-D in every combination. Somatic embryos developed to maturity on B5 medium containing glutamine, casein hydrolysate, 20 g liter-1 sucrose, 10% (v/v) coconut water and 1.7 g liter-1 Gelrite. Callus initiation and somatic embryo development occurred in darkness at 25°C. Mature somatic embryos germinated normally in the light.
Cryopreservation of embryogenic cultures induced from leaves of mature phase trees of Litchi chin... more Cryopreservation of embryogenic cultures induced from leaves of mature phase trees of Litchi chinensis Sonn. was performed following a vitrification method. Vitrification solution (PVS2) was utilized at two temperatures: 0 degree C and 25 degree C. Post-treatment survival percentages and regrowth rates of the cultures were higher when the PVS2 solution was at 0 degree C. All samples cryopreserved with PVS2 at 0 degree C survived; their regrowth rate after eight weeks on semi-solid maintenance medium was the same as non-treated controls. Cryopreservation suppressed somatic embryo development; the number of somatic embryos derived from cryopreserved cultures was less than the number obtained from the controls. Desiccation during the PVS2 treatment had no effect on reversal of hyperhydric embryogenic cultures.
Plasmodesmata have been demonstrated in three dicotyledon species between the stomatal guard cell... more Plasmodesmata have been demonstrated in three dicotyledon species between the stomatal guard cells and the accessory cells.
The cycads (Fig. 1) constitute remnant species of an ancient class of gymnosperms, the cycadophyt... more The cycads (Fig. 1) constitute remnant species of an ancient class of gymnosperms, the cycadophytes, that evolved from the free-sporing progymnosperms, which also gave rise to the coniferophytes. According to Gifford & Foster (1989), the cycadophytes have included 3 orders of plants, the extinct Cycadeoidales and Pteridospermales (seed ferns), that are known only from the fossil record, and the Cycadales,
World Journal of Microbiology & Biotechnology, 1995
Many important food and fibre crops have attained close to their maximum yields as a result of co... more Many important food and fibre crops have attained close to their maximum yields as a result of conventional breeding approaches and advances in agronomic and horticultural practices. The manipulation of cell and tissue cultures to produce somatic embryos efficiently is one of the keystones of the new technologies that will greatly alter the way crops are planted (as synthetic seed) and genetically altered in the future. Gene transfer into embryogenic plant cells is already challenging conventional plant breeding, and has become an indispensable tool for crop improvement. This review provides a current assessment of the impact of somatic embryogenesis in agriculture.
The mango Mangifera indica L. is considered to be one of the most important fruit crops of the wo... more The mango Mangifera indica L. is considered to be one of the most important fruit crops of the world (Fig. 1). Its annual production is exceeded only by Musa (bananas and plantains), citrus, grapes and apples (FAO Production Yearbook, 1990). Currently, it is the most important fruit crop of Asia. Mango is in the Anacardiaceae family, which includes several other tropical and subtropical tree species of economic importance, e.g., cashew Anacardium occidentale, pistachio Pistachia vera, and several Spondias species, including S. cytherea, S. mombin and S. purpurea. The center of diversity for the genus Mangifera is in southeast Asia, with the greatest number of species being found on the island of Borneo. According to Mukherjee (1985), there are 39 currently recognized Mangifera species. The mango is the most widely cultivated species within the genus, and has a natural distribution throughout outheast Asia. It is found in forests as far west as the Indo-Burman region (Assam). There appear to be two distinct geographical races of the species: a polyembryonic race that occurs in the tropical rainforest of southeast Asia and a monoembryonic race that is associated with India. Some taxonomists have suggested that the mango originated in India, because of the ancient association between Indian culture and religion with this fruit. It has also been noted that the word for mango used throughout Asia is derived from the Tamil “maanga”.
Summary Embryogenic callus was induced from leaflets of new vegetative flushes of mature longan (... more Summary Embryogenic callus was induced from leaflets of new vegetative flushes of mature longan (Euphoria longan Stend.) trees. Induction of embryogenic competency was dependent on the presence of auxin (2,4-D) and cytokinin (kinetin) in the growth medium (B5 with 400mg liter-1 glutamine, 60g liter-1 sucrose, 200 mg liter-1 casein hydrolysate and 1.7g liter-1 Gelrite). The optimum range of phytohormone concentrations was 0.25 - 2.0 mg liter-1 of kinetin and 2,4-D in every combination. Somatic embryos developed to maturity on B5 medium containing glutamine, casein hydrolysate, 20 g liter-1 sucrose, 10% (v/v) coconut water and 1.7 g liter-1 Gelrite. Callus initiation and somatic embryo development occurred in darkness at 25°C. Mature somatic embryos germinated normally in the light.
Cryopreservation of embryogenic cultures induced from leaves of mature phase trees of Litchi chin... more Cryopreservation of embryogenic cultures induced from leaves of mature phase trees of Litchi chinensis Sonn. was performed following a vitrification method. Vitrification solution (PVS2) was utilized at two temperatures: 0 degree C and 25 degree C. Post-treatment survival percentages and regrowth rates of the cultures were higher when the PVS2 solution was at 0 degree C. All samples cryopreserved with PVS2 at 0 degree C survived; their regrowth rate after eight weeks on semi-solid maintenance medium was the same as non-treated controls. Cryopreservation suppressed somatic embryo development; the number of somatic embryos derived from cryopreserved cultures was less than the number obtained from the controls. Desiccation during the PVS2 treatment had no effect on reversal of hyperhydric embryogenic cultures.
Plasmodesmata have been demonstrated in three dicotyledon species between the stomatal guard cell... more Plasmodesmata have been demonstrated in three dicotyledon species between the stomatal guard cells and the accessory cells.
The cycads (Fig. 1) constitute remnant species of an ancient class of gymnosperms, the cycadophyt... more The cycads (Fig. 1) constitute remnant species of an ancient class of gymnosperms, the cycadophytes, that evolved from the free-sporing progymnosperms, which also gave rise to the coniferophytes. According to Gifford & Foster (1989), the cycadophytes have included 3 orders of plants, the extinct Cycadeoidales and Pteridospermales (seed ferns), that are known only from the fossil record, and the Cycadales,
World Journal of Microbiology & Biotechnology, 1995
Many important food and fibre crops have attained close to their maximum yields as a result of co... more Many important food and fibre crops have attained close to their maximum yields as a result of conventional breeding approaches and advances in agronomic and horticultural practices. The manipulation of cell and tissue cultures to produce somatic embryos efficiently is one of the keystones of the new technologies that will greatly alter the way crops are planted (as synthetic seed) and genetically altered in the future. Gene transfer into embryogenic plant cells is already challenging conventional plant breeding, and has become an indispensable tool for crop improvement. This review provides a current assessment of the impact of somatic embryogenesis in agriculture.
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