ABSTRACT
The pathways of micro- and megagametophyte development in Agave fourcroydes (henequén) and A. angustifolia were studied. We used histology and light microscopy to observe anther ontogeny and ovary differentiation in relation to flower bud size. Both species have the same sexual reproductive strategies and gametophyte development that may be divided into three phases: (1) premeiotic, which includes the establishment of the megaspore mother cell and the pollen mother cell; (2) meiotic, the formation of mature microspores and functional megaspores; (3) postmeiotic, which encompasses the development of mature pollen grains and the formation of the embryo sac. A successive type microsporogenesis was found in both species with formation of T-shaped tetrads and binuclear pollen grains. In vitro germination tests revealed very low pollen fertility. The female gametophyte is formed from two micropylar megaspore cells after the first meiotic division (bisporic type). Male and female gametogenesis occur asynchronously with microsporogenesis finishing before macrosporogenesis. The results so far show that the formation of male and female gametophytes in henequén is affected at different stages and that these alterations might be responsible for the low fertility shown by this species.
ABSTRACT
Wild tomato plants of Lycopersicon peruvianum var. dentatum were transformed with pG11 plasmid having human beta-interferon (hIFN-beta) and NPTII genes. Transformation was demonstrated by polymerase chain reaction (PCR) and ELISA assay. Expression of hIFN-beta gene was identified by Western blot analysis. Transgenic plants produced seeds and F1 generation inherited integrated traits.
Subject(s)
Agrobacterium tumefaciens/genetics , Interferon-beta/genetics , Plasmids/genetics , Solanum lycopersicum/genetics , Transformation, Genetic/genetics , Anti-Bacterial Agents/antagonists & inhibitors , Base Sequence , DNA Primers , Enzyme-Linked Immunosorbent Assay , Gene Expression Regulation, Plant/genetics , Humans , Kanamycin/antagonists & inhibitors , Molecular Sequence Data , Plants, Genetically Modified , Polymerase Chain Reaction/methodsABSTRACT
The possibility of plant regeneration from leaf tissue, callus and callus protoplasts of Lycium barbarum L. has been studied. Leaf segments were cultured on B5 medium (Gamborg et al. 1968) containing 1.5 mg/1 6-benzylaminopurine and 0.5 mg/1 α-naphthaleneacetic acid. Regeneration of shoots was initiated after 30 days of cultivation. Callus was obtained from leaf and internode tissues on MS medium (Murashige and Skoog 1962) containing 0.4 mg/1 of 2,4dichlorophenoxyacetic acid. Subsequently, callus was successfully subcultured on the same medium with 1 mg/l of 2,4-dichlorophenoxyacetic acid and 0.2 mg/l α-naphthaleneacetic acid. Organogenesis in callus culture was obtained in the course of 40 days after transferring to TM-4 (Shahin 1984). Protoplasts were isolated from callus tissue grown in vitro using an enzymatic method. Cell colonies, minicallus formation and organogenesis were obtained. Shoots were rooted on Murashige and Skoog medium containing 0..1 mg/l α-naphthaleneacetic acid. Regenerated plants were transferred to soil and were grown to maturity. Regenerated plants carried normal morphological traits.
