promoting precocious maturation in muskmelon, tomato, and peach fruit ( Jimenez et al., 2002 ; Lacan and Baccou, 1998 ; Qin et al., 2009 ). Riboflavin, also known as vitamin B 2 , is an essential cofactor for many metabolic enzymes in multiple cellular
Mingtao Zhu, Jun Yu, Sheng Wu, Meijun Wang and Guoshun Yang
Shengrui Yao, Robert Heyduck and Steven Guldan
, and is precocious and productive with reasonable fruit quality. But, ‘Li’ is not suitable for all climate conditions, soil types, and different end uses. Nevertheless, growers in the United States tend to harvest ‘Li’ relatively early in the green
Ana Maria Sabja, David W.S. Mok and Machteld C. Mok
Interspecific hybrid embryos resulting from crosses between Phaseolus species generally fail to reach maturity, and embryo rescue techniques are required to recover plants. To determine if ovary (pod) culture could permit interspecific hybrid embryo development, pods of P. vulgaris L. × P. acutifolius A. Gray and P. vulgaris L. (control) were cultured upright, supported by glasswool, in modified Murashige-Skoog liquid medium. The weight of seeds and length of embryos in P. vulgaris pods increased significantly during culture. However, usually only one or occasionally two seeds located at the middle positions of the pods developed to maturity. The same pod culture procedure promoted precocious germination of early cotyledonary-stage P. vulgaris × P. acutifolius embryos without further maturation of the embryos. These findings confirm that developmental arrest of the interspecific hybrid embryos in vivo is due to intrinsic deficiencies.
Bihua Huang and Ellen G. Sutter
Development and maturation of somatic embryos is known to be abnormal in many species, particularly woody species. Precocious germination, abnormal cotyledon formation, and shoot development are three problems, among others, that occur during the growth and germination of walnut somatic embryos. Depending on the cultivar or line being cultured, as much as 50% of the embryos in any given culture may be abnormal. Reports in the literature have shown that ABA is useful in enhancing maturation and producing normal germination of somatic embryos of a variety of plant species. In order to overcome the difficulties of producing plants from somatic embryos in walnut, we have incorporated ABA in the nutrient medium in different concentrations and for different periods of time. Globular and cotyledonary embryos were separated and placed on DKW medium containing four different concentrations of ABA, 30, 60, 80, and 120 μM. Morphology, fresh weight, and germination of embryos grown on these different media were recorded. Embryos grown on ABA had lower fresh weight increases than controls, the actual growth depending on both the concentration of ABA present and the length of time the embryos were grown on ABA-containing media. In addition, the percentage of embryos with normal morphology was considerably higher when embryos were grown on ABA. Other factors that were affected by the presence of ABA included the total number of embryos produced and the amount of senescence in the cultures. Germination of embryos was also improved as a result of their being cultured on ABA-containing media.
Daksha Sankhla, Tim D. Davis and N. Sankhla
This study was initiated to test the embryogenic potential of immature cotyledons (3-5 mm long) of Texas bluebonnet (Lupinus texensis). The embryo initiation medium consisted of B5 salts and vitamins with 3% sucrose and 22.6 μM 2,4-D alone or in combination with 1-15 μM of various cytokinins. Within 15-20 days, globular embryos were formed on the distal end of the cotyledons. Eventually the entire cotyledon surface was covered by embryo-like structures. Addition of cytokinins to the medium did not increase the percentage of cultures which formed embryos. In fact, addition of thidiazuron severely inhibited embryogenesis. Following transfer to an embryo maturation medium (MS medium with 0.38 μM abscisic acid alone or in combination with benzyladenine or zeatin) for 10-14 days, the embryos were placed in MS medium supplemented with GA (2.9 μM) or glutamine (200 mg/liter) with or without activated charcoal (0.5%) for embryo germination and plantlet development. Most of the embryos exhibited precocious germination and well-developed roots but failed to produce normal shoots. Therefore, additional work is needed to improve embryo conversion frequency.
Juan Bernardo Pérez-Hernández and María José Grajal-Martín
for the successful culture of zygotic mango embryos. In this context, Pateña et al. (2002) effectively controlled browning of nucellar explants by adding coconut water to the embryogenesis induction medium. In addition, maturation of somatic embryos
Samuel Salazar-García, Luis E. Cossio-Vargas, Isidro J.L. González-Durán and Carol J. Lovatt
California caused precocious development of the vegetative bud of indeterminate floral shoots relative to the development of the flowers ( Salazar-García and Lovatt, 2000 ). The results of this prior research identified treatments that could be used to
Konstantinos Kazantzis, Thomas Sotiropoulos, Simeon Marnasidis, Ioannis Ganopoulos, Aliki Xanthopoulou and Panagiotis Madesis
‘Tragana Edessis’ ( Table 2 ). Table 2. Data of anthesis, maturation, and leaf shedding periods of the cultivars Bigarreau Burlat, Tsolakeiko, and Tragana Edessis during a period of 4 years. The fruits of ‘Tsolakeiko’ are symmetrical, heart shaped, and of
Vladimir Orbović, Manjul Dutt and Jude W. Grosser
inappropriate quality when precocious germination was observed in the grapefruits ( Fig. 1 ) or fruits had begun to fall off the tree in ‘Hamlin’ sweet orange. Fig. 1. Vivipary in ‘Duncan’ grapefruit. ‘Duncan’ and ‘Hamlin’ seeds collected during the first month
Ying Gao, Hao Liu, Ningguang Dong and Dong Pei
contribution to understanding of the IAA mechanism at the cellular level during flower bud differentiation. This work will promote improved production and breeding of walnut. Materials and Methods Plant material. We used the protandrous precocious walnut