Screening of Photoinsensitive Summer Rice (Oryza sativa L.) Genotypes for Ratoon Cropping

Of the 24 genotypes screened for ratooning ability and ratoon grain yield, only ten showed regeneration. RP 1664-4461 had the highest regeneration. Ratoon growth duration varied from 49–61 days. Ratoon grain yield was highest (1.7 t/ha) for RP 1664-4461 and the lowest (0.8 t/ha) for IET 7613. Productivity per day in the ratoon crop was comparable to that of the main crop. Based on grain yield and per day productivity of main and ratoon crops, cultures CR 222 MW 10, Rasi, RP 1664-4461, RP 1165-132-1 and CR 215-55-54-1 appeared promising for ratoon cropping.     

The Influence of Dicamba on Somatic Embryogenesis and Frequency of Plant Regeneration from Cultured Immature Embryos of Wheat (Triticum aestivum L.)

An investigation was made to discover the influence of dicamba on the somatic embryogenesis of winter wheat cultivars-. Immature embryos of Triticum aestivum cv, ‘Sage’, ‘Caribo’ and ‘Kanzler’ were cultured, on modified N6-medium with the addition of 1 mg/13,6 dichlor-2-methoxy benzoe acid (dicamba). The young embryos were placed with the embryo axis on to the medium. Under this condition the scutella of the embryos at different stage of development produced compact calli and embryoids which regenerated plants with a high frequency (70 %) four to: six weeks later. The results suggest that dicamba could be of value in the induction of somatic embryogenesis.     

Somatic Embryogenesis and Plant Regeneration from Tritordeum

Regeneration of plants by somatic embryogenesis from immature embryos of hexaploid tritordeum (AABBH^chH^ch, amphiploid Hordeum chilense×Triticum turgidum conv. durum) and durum wheat (Triticum tergidum) was induced on MS medium supplemented with different 2.4-D concentrations. Well-defined embryoids were formed with a high frequency on the scutellar callus from 1 or 2 weeks onwards and plantlets were developed from them. In the best cases from one single explant more than 100 plants could be obtained. Plants were also regenerated by somatic embryogenesis from inflorescences of Hordeum chilense×Triticum turgiditm conv. durum hybrid and its respective hexa-amphiploid. With regard to callus induction and regenerative ability, evident differences between hexa- and octoploid (H. chilense×T. aestivum) tritordeum were found, the latter showing a very low response.     

曼地亚红豆杉离体培养及植株再生

以红豆杉带侧芽茎段为外植体进行离体繁殖.结果表明:在WPM、MS、B53种基本培养基中,WPM为红豆杉离体培养最适的基本培养基;初代培养的最适培养基为WPM+4.0mg·L-12-ip+30.0mg·L-1Ad;芽继代增殖的最适培养基为WPM+4.0mg·L-12-ip+1.0mg·L-1IAA;生根壮苗的最适培养基为1/2WPM+0.5mg·L-1IBA+0.1mg·L-1NAA.     

鸡脚草、牛尾草在放牧条件下体内糖分含量积累动态与再生速度关系的研究

在人工放牧地上研究了鸡脚草、牛尾草体内糖分含量的积累与放牧后再生速度、温度的关系；糖分含量的积累与化学成分含量的关系等。研究结果表明：两种牧草的茎叶部和根部糖分含量的积累均随着温度升高，放牧后再生速度加快而减少；随着温度降低，再生速度缓慢，糖分含量积累显著增加。两种牧草茎叶部糖分含量均高于根部。鸡脚草茎叶部糖分含量略高于牛尾草，而牛尾草根部糖分含量高于鸡脚草。两种牧草体内糖分含量的积累与化学成分含量尚未发现明显规律性的变化。根据研究结果提出了合理利用人工草地的建议。     

实美橙子叶培养和植株再生

以实美橙子叶为外植体,在含2.4-D 1.0mgL~(-1),6-BA 0.5mgL~(-1)的MT 培养基上诱导愈伤组织,并将其在相同的培养基上继代增殖。在附加IBA 0.5～1.0mgL~(-1),6-BA 1.5～3.0mgL~(-1)的MT 分化培养基上培养近1月后,愈伤组织分化产生大量不定芽,长至2.0cm高时,在含NAA 0.5L~(-1),KT 0.05~mgL~(-1)的MT 生根培养基中诱导成完整的再生小植株。     

Regeneration through somatic embryogenesis from petal-derived calli of Rosa hybrida L. cv arizona (hybrid tea)

Summary Somatic embryogenesis in callus cultures of petal explants of rose cv arizona is reported here. The calli from petals initiated on dicamba containing medium were friable and gave rise to embryos after several subcultures while those obtained from other explants did not show embryogenesis. Abscisic acid and phloroglucinol were necessary during maturation and plant development, respectively. The individual embryos grew into true-to-type plants.     

Rho kinase inhibitor fasudil improves cognitive function by promoting nerve regeneration in APP/PS1 double transgenic mice

AIM:To observe the effects of Rho kinase inhibitor fasudil on promoting nerve regeneration and improving cognitive function in amyloid precursor protein/presenilin 1 double transgenic (APP/PS1 Tg) mice, a widely used model of Alzheimer disease. METHODS:Male APP/PS1 Tg mice at 8 months old were randomly divided into 2 groups:the mice in fasudil group were intraperitoneally injected with fasudil at 25 mg/kg, while the mice in NS group were intraperitoneally injected with normal saline (NS), once daily for 2 months. Age-and sex-matched wild-type (WT) mice without treatment were used as controls. The Morris water maze (MWM) test and SMART 3.0 behavioral record system were applied to examine and analyze the spatial cognitive function of the mice. The protein levels and distribution of p-Tau, ChAT, BrdU and nestin in the hippocampal dentate gyrus (DG) and CA3 area and cerebral cortex were detected by immunohistochemistry. The protein levels of p-APP(Thr668) and p-Tau in the brain were analyzed by Western blot. RESULTS:Compared with control group, the APP/PS1 Tg mice (10 months old at the time of testing) treated with NS displayed the increase in the latency to target, and the decreases in the time and distance in SW (%) during the MWM test (SW was located in the area of the platform), indicating impaired cognition, which was reversed by fasudil treatment, indicating that the cognitive function was improved in the APP/PS1 Tg mice. In addition, compared with NS group, fasudil treatment significantly reduced the protein level of p-Tau, and increased the protein level of p-APP in the central nervous system (CNS) and the number of cholinergic neurons in the hippocampus. The neuronal axon regeneration in the hippocampus was promoted, and the endogenous neural stem cell proliferation in subgranular zone and subventricular zone of the hippocampal DG was also mobilized. CONCLUSION:Fasudil reverses spatial cognitive dysfunction in APP/PS1 Tg mice through decreasing the protein level of p-Tau, increasing the level of soluble APP, promoting the regeneration of cholinergic neurons, and mobilizating the endogenous neural stem cell proliferation in the CNS.     

Optimisation of a highly efficient shoot regeneration system using leaf explants of Chinese jujube (Ziziphus jujuba Mill.) by response surface methodology

Chinese jujube (Ziziphus jujuba Mill.) is a major fruit crop in Asia. In this study, response surface methodology (RSM) was successfully employed to establish a highly efficient in vitro propagation and regeneration system for the ‘Teapot’ jujube via shoot organogenesis. Among the tested factors, gibberellic acid (GA₃) concentration showed the most significant positive effect. The pre-culture darkness timing and medium were also important factors for highly efficient shoot regeneration of the ‘Teapot’ jujube. The highest regeneration (> 75%) was achieved by 1 week in darkness and culture on wood plant medium (WPM) containing 0.25 mg·L^?1 GA₃, 0.5 mg·L^?1 6-benzylaminopurine (BAP) and 0.1 mg·L^?1 3-indoleacetic acid (IAA). In vitro-derived shoots rooted very well in the modified ¹/₂ Murashige and Skoog (MS) medium containing 0.4 mg·L^?1 3-indolebutyric acid (IBA), resulting in a 100% rooting rate. These findings suggest that the RSM can be employed to optimise the protocols needed for successful in vitro plant regeneration of jujube cultivars, with potential applications in plant genetic transformation practices, polyploidy induction and germplasm preservation.     

Imposed starvation for in vitro maintenance and high regeneration of elite key lime (Citrus aurantifolia)

Preservation of elite key lime (Citrus aurantifolia) genotypes using efficient micropropagation and regeneration protocols is very important for new breeding programmes. The objective of the present study was to develop an efficient protocol for micropropagation and maintenance of elite genotypes of key lime based on slow growth and starvation strategy. To do this, regenerated shoots were starved, and the growth was compromised via avoiding subcultures for 4, 8, 12 and 24 months. The numbers of responsive explants and adventitious shoots per each explant were evaluated in the presence of benzylaminopurine (BAP). The results showed that the 12- and 24-month starved explants treated with 1 mg/l BAP were able to produce four times more shoots than the control. In addition, the influences of horizontal or vertical layering explants over medium were evaluated. The results indicated that all horizontally layered explants significantly produced 25% adventitious shoots more than vertical explants, most likely owing to more contact with the surface medium. Finally, it could be concluded that application of slow growth, starvation strategy and also horizontally layering of the explants could efficiently enhance micropropagation and maintenance of threatened elite key lime genotypes with a low cost.