T. D. Hong

Bio: T. D. Hong is an academic researcher. The author has contributed to research in topics: Coffea arabica. The author has an hindex of 1, co-authored 1 publications receiving 57 citations.

Coffee seed physiology

Abstract: Considerable advances in our understanding of coffee seed physiology have been made in recent years. However, despite intense research efforts, there are many aspects that remain unclear. This paper gives an overview of the current understanding of the more important features concerning coffee seed physiology, and provides information on recent findings on seed development, germination, storage and longevity.Key words: Coffea, coffee, germination, germplasm, longevity, seed development, storage.Fisiologia da semente do cafeeiro: Avancos consideraveis no entendimento da fisiologia de sementes do cafeeiro foram obtidos nos ultimos anos. No entanto, apesar da extensa literatura, muitos aspectos permanecem obscuros. Este trabalho descreve o estado atual do conhecimento sobre as principais caracteristicas da fisiologia de sementes de cafeeiro, assim como os recentes trabalhos sobre o desenvolvimento, germinacao, armazenamento e longevidade das sementes.Palavras-chave: Coffea, armazenamento, cafe, desenvolvimento, germinacao, germoplasma, longevidade.INTRODUCTIONCoffee is a member of the Rubiaceae family and the genus Coffea. There are more than 70 species of coffee but only two are economically important: Coffea arabica L. and Coffea canephora Pierre; 70 % of the coffee traded in the world is arabica and 30 % is robusta (C. canephora). Other species such as C. congensis, C. dewevrei and C. racemosa have some interesting genetic characteristics, including resistance to pests and diseases and are used in breeding programs. To satisfy the demand for coffee within Brazil and around the world, intensive breeding programs have been undertaken to create new cultivars which are resistant to diseases and insects, and to incorporate new traits of value. In addition, new production and processing technologies are introduced every year, which have led to an enormous improvement in coffee production. Although progress has been made, not many studies have been devoted to the improvement of coffee seed quality for propagation.The purpose of this paper is to review our understanding of coffee seed physiology. Most of the work published in the literature and reported in this paper is on C. arabica seeds, although some aspects of C. canephora seed physiology are also included. Knowledge of seed physiology of other Coffea species is poor, with the exception of storage physiology, which is mostly related to germplasm conservation. Although this review will discuss some aspects of seed development and morphology, germination and storage physiology, the focus will be on germinability, and desiccation tolerance, with emphasis on the conservation of genetic resources. THE COFFEE SEEDThe coffee seed is elliptical or egg-shaped, plane-convex, possessing a longitudinal furrow on the plane surface (Dedecca, 1957). The outer cover of the seed is formed by a hard pale brown endocarp that becomes the “parchment” after drying. The endocarp contains an enclosed seed, which has

Desiccation sensitivity and cell cycle aspects in seeds of Inga vera subsp. affinis

Abstract: The desiccation sensitivity of seeds of Inga vera Willd. subsp. affinis, a recalcitrant-seeded tree from Brazil, was analysed, focusing on water relations and cell-cycle aspects, including DNA content and the microtubular cytoskeleton. Seeds were collected at four developmental stages, dried to different moisture contents (MCs), assessed regarding water activity and set to germinate. Samples of fresh (non-dried) developing and mature seeds were used for assessment of DNA content by flow cytometry. Immunohistochemical detection of microtubules (MTs) was done in mature seeds at different MCs. Slight desiccation of immature seeds increased germination, but further drying resulted in a quick decline of germinability. During seed development the desiccation sensitivity decreased slightly, but DNA content of the embryonic axis cells remained constant, suggesting no relation between those two parameters. Embryonic axis cells of mature seeds showed abundant cortical microtubule arrays, which were not affected by mild desiccation, but broken down by further drying. It appeared that, upon rehydration, damaged cells were not able to reconstitute the microtubular cytoskeleton. The failure of germination of Inga vera seeds after drying could not be attributed to cellular damage to DNA synthesis and mitosis, since the radicle protruded by means of cell elongation, without a need for cell division. However, the breakdown of MTs during desiccation, and their subsequent inability to reassemble upon rehydration, may be related to the decreased germination, since MTs are required for cell elongation.

Tolerância à dessecação de sementes de palmito-vermelho (Euterpe espiritosantensis Fernandes)

Abstract: With the objective of identifying the desiccation tolerance of Euterpe espiritosantensis seeds, two lots of fruits were picked in the collection of palm trees of the Agronomic Institute of Campinas (Ubatuba, State of Sao Paulo) and transported in impermeable packing to Faculdade de Ciencias Agronomicas/UNESP Botucatu (State of Sao Paulo), where they were shelled. The seeds were submitted to drying in silica gel, starting from the non-dehydrated control (51.4% and 46.6% of initial water content), taking samples at each 12 or 24 hours. The effects of dehydration were evaluated by means of germination test, percentage and speed of embryo protrusion, botton, plumule, and seedlings length. Seed dry matter and water content were also evaluated. It was concluded that the seeds of E. espiritosantensis are recalcitrant, presenting higher initial percentage of germination (90.0% to 87.5%) when not dehydrated (51.4% to 46.6% of water content). Water contents lower than 40.7%-51.4% reduced the vigour and germination rates. All seeds died when the water contents were lower than 13.4%-15.8%.

Desidratação de sementes de quatro lotes de pupunheira: efeitos sobre a germinação e o vigor

Abstract: Dehydration effects on germination and vigor of four pejibayeseed lots The dessication tolerance of four seed lots of spineless pejibaye( Bactris gasipaes Kunth) harvested at Yurimaguas (Peru); Camamuand Pirai do Norte (Bahia State, Brazil) and Pindorama (Sao PauloState, Brazil) was identified. The seeds were dried in a dryingchamber starting with undried controls. Samples were drawn every24 hours. Dessication effects were evaluated by means of germinationtest (until 184 days, vermiculite, 20-30 o C), germination first counting(36 days), germination speed and seed water content. It was verifiedthat seeds from that species are susceptible to dehydration, withhigher initial germination percentage (59 to 84%) when undried (47to 38% of water content). Water contents lower than 28 to 23%reduced significantly seed germination and vigor. All seeds died whenthe seed water content was lower than 15% (seed lots 2 and 4) and13% (seed lots 1 and 3). Keywords : Bactris gasipaes , peach palm, seed deterioration,recalcitrance, critical water content, lethal water content.