香花槐花器官的组织培养及植株再生研究

采用香花槐的花器官做外植体,进行组织培养和植株再生系统的研究.结果表明:2,4-D对于香花槐愈伤诱导的启动是必需的,而多种激素配比会使诱导率提高;选择浓度为0.3～0.5 mg/L的BA和浓度为0.1 mg/L的NAA配合使用,能使花药愈伤达到较高分化率;1/2MS IBA 0.05 mg/L和1/2MS IBA 1.0 mg/L的诱导组培苗生根效果较好.     

黄瓜子叶外植体组培成株研究

采用正交试验设计,研究了不同激素浓度组合对黄瓜子叶离傣再生的影响.结果表明:愈伤组织诱导培养基为MS 1.0 mg/L 6-BA (1.0～1.5)mg/L KT 0.3 mg/L NAA 0.1mg/L2,4-D;不定芽诱导培养基为MS 6-BA1.5 mg/L NAA0.3 mg/L,再生芽移入生根培养基(MS 0.1 mg/L NAA)生根培养,40～60 d可得到完整再生植株.另外,在所有组合中,6-BA浓度1.5 mg/L时,愈伤组织诱导率低,并且出现了愈伤化现象,引起器官直接分化.     

花椰菜—黑芥体细胞杂种的性状演变和对黑腐病抗性的转育

以对黑腐病(Black rot)感病的花椰菜(Brassica oleracea L.var.botrytis L.,2n=18,CC)‘Korso’和抗病的黑芥(B.nigra,black mustard,2n=16,BB)‘G1/1’的体细胞杂种(简称PFCN,protoplast fusion of cauliflower and Brassica nigra)高代自交及回交后代为材料,根据表型特征将其分为4大类:性状介于花椰菜和黑芥之间的中间型材料(M)、向花椰菜过渡的过渡型(M-K)、偏花椰菜型(-K)和花椰菜型(K)。连续5年的黑腐病人工接种鉴定结果显示:‘Korso’的病情指数在44~57之间,表现为耐病到感病;‘G1/1’在12~32之间,表现为抗病,从M、M-K、-K至K型,杂种后代病情指数总体上呈逐渐升高的趋势,其中M型和M-K型材料表现为高抗至抗病,-K型材料表现为抗病至耐病,K型材料表现为耐病。对2014年的15份典型-K至K型材料进行了形态演变及黑腐病抗性变化追溯:总体上,偏花椰菜的形态转变发生在S1BC4、S5、S1BC3和BC3(S为自交,BC为回交)世代中,伴随着形态的转变,黑腐病病情指数急剧升高;同一年中来源相同或者相近的株系病情指数相差不多。2015年进一步对2014年25个单株的自交后代进行黑腐病抗病性跟踪鉴定:整体上病情指数呈下降趋势,仅少数株系表现上升;来源相同的衍生株系变化趋势几乎一致,且差异不大,说明这些材料系内对黑腐病抗病性逐年趋于稳定。目前获得了6份相对于受体亲本‘Korso’表现出了对黑腐病抗性显著提高的材料:PFCN14-15-4.1、PFCN14-15-5.1、PFCN14-29-1.1和PFCN14-29-1.2,连续3年病情指数呈下降趋势,并最终稳定在30左右;PFCN14-14-1.1和PFCN14-14-1.2则连续6年保持在20~38之间。     

朱顶红‘Red Lion’胚性愈伤组织诱导及体细胞胚发生

以‘Red Lion’朱顶红(Hippeastrum vittatum)的鳞片为外植体进行体细胞胚诱导和形态学与组织学的胚性鉴定。结果表明,鳞片在MS+2 mg·L~(-1) BA+1 mg·L~(-1) NAA+2 mg·L~(-1) TDZ+30 g·L~(-1)蔗糖培养基上胚性愈伤组织诱导率可达90.63%,而不添加TDZ的培养基上胚性愈伤组织诱导率为0。胚性愈伤组织可呈白色松散、透明膨松、透明致密、微棕色松脆和翠绿色松脆等类型;非胚性愈伤组织呈微棕色致密状。胚性愈伤组织中可明显观察到球形胚、心形胚和棒状胚3个发育时期。体细胞胚在不添加植物生长调节剂的MS培养基上可发育形成芽和根,长成完整小植株。     

Botulinum neurotoxin type A heavy chain intervenes in expression of general proteins in spinal cord after unilateral spinal cord injury in rats

AIM: To observe the effect of botulinum neurotoxin type A heavy chain (BoNT/A HC) on the pattern of spinal protein expression by intrathecal injection after spinal cord injury in rats, and to explore the role of BoNT/A HC intervention in spinal protein expression and some of its mechanisms in nerve regeneration after injury. METHODS: The model of unilateral lumbar spinal cord injury was established. The effects of BoNT/A HC intervention at different doses (2 μg, 4 μg, 6 μg and 8 μg) on the general pattern of protein expression in the spinal cord tissues at the injury site and the cranial part adjacent to the injury site was measured and evaluated by SDS-PAGE and Coomassie brilliant blue staining first, and then by two-dimensional SDS-PAGE. RESULTS: The histological structure of the ipsilateral side of lumbar spinal cord showed obvious destruction and degradation, mainly affecting both gray and white matter of the left side of the cord. The result of SDS-PAGE with Coomassie brilliant blue staining from injured spinal cord tissue displayed that the expression of some proteins after one-time BoNT/A HC treatment appeared obviously different from that without BoNT/A HC treatment. Moreover, the pattern of the protein expression affected by BoNT/A HC was similar to that of the normal spinal cord. The more detail information from two-dimensional SDS-PAGE indicated that more than 10 proteins with different molecular weight and isoelectronic points were differentially expressed at day 2 and day 20 after local injection of 6 μg BoNT/A HC. This altered expression actually appeared a tendency toward the pattern shown in normal group. CONCLUSION: The immediate application of BoNT/A HC at the injury site after unilateral lumbar spinal cord injury is able to affect the pattern of local protein expression. The altered protein expression by injury could be reversed back to normal or approximately normal by local BoNT/A HC administration.     

Developmental horizons in the pre‐natal development of the Greater cane rat (Thryonomys swinderianus)

The Greater cane rat (GCR, Thyronomys swinderianus) is a precocial rodent predominantly found within Africa. Economic and scientific interests have led to several research efforts towards the domestication and better understanding of the biology and development of this rodent. Despite these efforts, information on the pre‐natal development of this rodent is currently lacking. This study characterises distinct developmental milestones including skin pigmentation, emergence and distributions of hairs, calvarium consistency, teeth eruption, development of appendages, sensory organs and external genitalia in the pre‐natal GCR and assesses quantitative body parameters, that is body weight, body and crown–rump lengths across its entire gestation length (gestation days [GDs] 10‐140). Using these external features, we provide baseline reference ontogenetic scales for GCR embryos and fetuses, employable for stage, age and sex estimation of the pre‐natal GCR in future studies. We observed that the first evidence of an embryo was not seen before the end of the first trimester (GD50) and that the late second trimester (GD80‐GD100) marks the transition from embryogenesis to fetogenesis in the GCR. As both events occur at a much later developmental time point when compared to precocial non‐rodents including human, sheep and pig and slightly later when compared to other precocial rodents such as guinea pig, our data provide first indication that the pre‐natal GCR development might be associated with a reproductive delay. Together, this study expands our knowledge of the development and biology of the GCR, which will improve reproductive and breeding management, and native species conservation of this hystricomorph mammal.     

Comparative study of the developmental competence of cloned pig embryos derived from spermatogonial stem cells and fetal fibroblasts

Spermatogonial stem cells (SSC) are promising resources for genetic preservation and restoration of male germ cells in humans and animals. However, no studies have used SSC as donor nuclei in pig somatic cell nuclear transfer (SCNT). This study investigated the potential for use of porcine SSC as a nuclei donor for SCNT and developmental competence of SSC‐derived cloned embryos. In addition, demecolcine was investigated to determine whether it could prevent rupture of SSC during SCNT. When the potential of SSC to support embryonic development after SCNT was compared with that of foetal fibroblasts (FF), SSC‐derived SCNT embryos showed a higher (p < .05) developmental competence to the blastocyst stage (47.8%) than FF‐derived embryos (25.6%). However, when SSC were used as donor nuclei in the SCNT process, cell fusion rates were lower (p < .05) than when FF were used (61.9% vs. 75.8%). Treatment of SSC with demecolcine significantly (p < .05) decreased rupture of SSC during the SCNT procedure (7.5% vs. 18.8%) and increased fusion of cell‐oocyte couplets compared with no treatment (74.6% vs. 61.6%). In addition, SSC‐derived SCNT embryos showed higher blastocyst formation (48.4%) than FF‐derived embryos without (28.4%) and with demecolcine treatment (17.4%), even after demecolcine treatment. Our results demonstrate that porcine SSC are a desirable donor cell type for production of SCNT pig embryos and that demecolcine increases production efficiency of cloned embryos by inhibiting rupture of nuclei donor SSC during SCNT.     

Effect of frugivorous birds on the establishment of a naturally regenerating population of Chinese yew in ex situ conservation

The Chinese yew (Taxus chinensis) is catalogued as an endangered species in China because of the small size and senescent status of most populations. Its lack of natural regeneration is the most important reason for its endangered status. We investigated the regeneration of an ex‐situ conservation population, which was introduced into the Nanjing Botanical Garden Memorial Sun Yat‐Sen in the 1950s, and evaluated the role of frugivorous birds on the establishment of this regenerating population. Two hundred and thirteen individual yew seedlings and saplings were found on the hillside in 2006, and the nearest seedling was found more than 10 m away from mother trees. The spatial pattern of all seedlings and saplings occurred as a clumped distribution, which is typical for vertebrate‐dispersed plants. Six bird species were seen ingesting whole “fruits” at yew trees in the present study and 745 visits by avian frugivores were recorded. Red‐billed blue magpie (Urocissa erythrorhyncha), Chinese bulbul (Pycnonotus sinensis) and azure‐winged magpie (Cyanopica cyana) were the most frequent visitors over the two years of the study. Comparing the flights of departure and perching habitats of the three main bird species, we inferred that U. erythrorhyncha would be the most important disperser. This regeneration population has had good development over the past 20 or more years; frugivorous birds have removed seeds to the hillside every year until now, and seed germination and seedling growth continue to develop well under natural conditions. We suggest that the conservation system of the Chinese yew should be composed of yews, avian dispersers and habitats for seed germination and seedling growth.     

Influence of potential growth factors on the production of proembryogenic masses of Cyclamen persicum Mill. in bioreactors

Propagation in liquid culture, especially bioreactors, is one possible way to produce clonal propagules of Cyclamen persicum Mill. at a low cost. The current propagation method for C. persicum is from expensive hybrid seeds. This paper presents models of the potential effects of oxygen concentration, daily mean temperature, the difference between day and night temperature (DIF), and daily light integral on the development of proembryogenic masses of C. persicum Mill. in bioreactors. Each of the four growth factors was observed at three levels; oxygen concentration (50, 100 and 150% of fully oxygen saturated medium without cells), daily mean temperature (15, 20 and 25 °C), DIF (+10, 0 and −10) and daily light integral (0, 1.3 and 2.6 mol m⁻² day⁻¹). Two response variables, biomass growth and cell viability, were measured at day 0, 7, 14, 21 and 28 after start-up. The optimal values for biomass growth were 150% oxygen, 25 °C, 1.11 mol m⁻² day⁻¹ and DIF + 10. There was a stable positive linear effect from temperature. Oxygen showed a similar, but less stable effect. DIF gave maximum effect at the outer levels, and its optimum was the upper level +10. The optimal values for light were between 1.03 and 1.19 mol m⁻² day⁻¹. The optimal time for cell viability in the bioreactors was 10–11 days. Temperature and daily light integral had stable optima of 20.8 °C and 1.10 mol m⁻² day⁻¹. For oxygen the optimum was more unstable, but in most cases it was below 100%. There was no significant effect of DIF on cell viability.     

Root restriction-induced limitation to photosynthesis in tomato (Lycopersicon esculentum Mill.) leaves

Root restriction often depresses photosynthetic capacity and the mechanism for this reduction, however, remains unclear. To identify the mechanism by which root restriction affects the photosynthetic characteristics, tomato (Lycopersicon esculentum Mill.) seedlings were subjected to root restriction stress with or without supplemental aeration to the nutrient solution. With the development of the root restriction stress, CO₂ assimilation rate was decreased only in confined plants without supplemental aeration. There were also significant decreases in leaf water potential, stomatal conductance (g_s), intercellular CO₂ concentration (C_i), and increases in the stomatal limitation (l) and the xylem sap ABA concentration. Meanwhile, the maximum carboxylation rate of Rubisco (V_cmax) and the capacity for ribulose-1,5-bisphosphate regeneration (J_max) also decreased, followed by substantial reductions in the quantum yield of PSII electron transport (Φ_PSII). Additionally, root restriction resulted in accumulation of carbohydrates in various plant tissues irrespective of aeration conditions. It is likely that root restriction-induced depression of photosynthesis was mimicked by water stress.