High efficiency adventive embryogenesis on somatic embryos of anther,filament and immature proembryo origin in horse-chestnut (Aesculus hippocastanum L.) tissue culture

Adventive embryogenesis was successfully induced in cultures of zygotic and somatic embryos on MS medium supplemented with BA and NAA. A procedure has been proved successful for the in vitro multiplication of somatic embryos regenerated at low frequencies from filament and callus cultures. The occurrence and rate of adventive embryogenesis did not depend on the origin of the primary embryos (zygotic and somatic), but did depend on the developmental stage. Primary embryos are capable of embryogenesis in each of the different phases of embryogenesis, though the rate is different. BA concentrations of 22–44 M increased the rate of adventive embryogenesis and accelerated the development of embryos. The highest proliferation rate (22–25x/5 weeks) was achieved at hormone concentrations of 44 M BA and 5.4 M NAA.Abbreviations BA benzyladenine - CH casein hydrolysate - CM coconut milk - 2,4-D dichlorophenoxyacetic acid - MS Murashige & Skoog medium - WPM woody plant medium - NAA 1-naphtaleneacetic acid     

The effect of explant material on somatic embryogenesis of Cyclamen persicum Mill

Somatic embryos of Cyclamen persicum Mill. could be produced through a callus phase from juvenile explant material including anthers, ovaries and zygotic embryos. The auxin 2,4-D (1.0–1.5 mg l^-1) and coconut milk (10% v/v) in MS medium were important factors for the induction of somatic embryogenesis. Somatic embryos germinated into plantlets in MS medium without growth regulators. The plants grew well in the greenhouse and flowered normally. The plants were phenotypically identical to the mother plants with a few exceptions.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - NAA 1-naphthylacetic acid - IAA 3-indoleacetic acid - BA 6-benzyladenine - ABA abscisic acid - CM coconut milk     

Pollen viability assessments in blackberries (Rubus subgen.Rubus)

Pollen viability has been investigated in 20 blackberry species using 3 methods, (1) cotton blue, (2) TTC, and (3) germination in a sucrose solution. Significant differences were found between species. Correlations between high pollen viability and high seed set were also obtained.     

Pollen morphology inLinum sect.Macrantholinum

Pollen of the two distylous species which make upLinum sect.Macrantholinum differs from that of other distylous species in the genus in being multiporate and in having much more modest differences in exine sculpturing between grains from long- and short-styled plants. Pollen morphology does not help in relating the two species to others in the genus but does support their retention in a separate section.     

蚕豆花粉母细胞染色体畸变同染色质胞间转移的关系

采用压碎、石蜡切片及植物染色体分带技术观察蚕豆花粉母细胞减数分裂过程发现:1.蚕豆花粉母细胞减数分裂的凝线期也出现染色质胞间转移现象;2.在8.08%的花粉母细胞内,染色体偏离正常的数目(n=6);3.染色体结构也有显著改变,其中包括染色体断裂、桥和长度的增减;4.出现双核和无核的花粉母细胞。大量证据表明,这些畸变现象同凝线期的染色质胞间转移有关。     

Bicoid gradient formation mechanism and dynamics revealed by protein lifetime analysis

Embryogenesis relies on instructions provided by spatially organized signaling molecules known as morphogens. Understanding the principles behind morphogen distribution and how cells interpret locally this information remains a major challenge in developmental biology. Here, we introduce morphogen‐age measurements as a novel approach to test models of morphogen gradient formation. Using a tandem fluorescent timer as a protein age sensor, we find a gradient of increasing age of Bicoid along the anterior–posterior axis in the early Drosophila embryo. Quantitative analysis of the protein age distribution across the embryo reveals that the synthesis–diffusion–degradation model is the most likely model underlying Bicoid gradient formation, and rules out other hypotheses for gradient formation. Moreover, we show that the timer can detect transitions in the dynamics associated with syncytial cellularization. Our results provide new insight into Bicoid gradient formation and demonstrate how morphogen‐age information can complement knowledge about movement, abundance, and distribution, which should be widely applicable to other systems.     

In vitro biotechnological advancements in Malabar nut (Adhatoda vasica Nees): Achievements,status and prospects

Adhatoda vasica Nees, belonging to family Acanthaceae, is a well-known medicinal plant. It is endorsed for its pyrroloquinazoline alkaloids and its derivatives, such as vasicine and vasicinone. Germinating A. vasica seeds is a tedious task; on that account, vegetative propagation is the preferred method for its multiplication. For rapid and large-scale multiplication, germplasm conservation as well as secondary metabolites production, in vitro culture of A. vasica was preferred over conventional propagation by several researchers; however, some major applications of this tissue culture technique are still awaiting to undergo extensive research. The present review, for the first time, illustrates all the major achievements associated with in vitro regeneration of A. vasica, reported till date and highlights the future prospects.