平阴玫瑰花芽分化期叶片内源激素的变化

对平阴玫瑰花芽分化期叶片甲醇提取物进行IAA、ZR、GA₃、ABA的分离、纯化和测定。结果发现,所测的几种激素均表现出明显的变化规律,其中IAA和GA₃在花芽分化期含量逐渐下降,且在分化临界期出现一低峰,而ZR和ABA则完全相反。同时经比较分析得出ABA/GA₃, ABA/IAA,ZR/GA₃,ZR/IAA也表现明显的变化规律,即比值总体趋势是逐渐提高,且均在分化临界期含量出现一飞跃,显然ABA/GA3,ABA/IAA,ZR/GA₃,ZR/IAA在平阴玫瑰的花芽分化过程中起着重要的调控作用,由此推测,增加植物体内的ABA、ZR的含量或降低IAA、GA₃的含量,都可以促进玫瑰的花芽分化;反之则抑制其花芽分化。     

斜带石斑鱼囊胚期胚胎和尾芽期胚胎差异表达基因的筛选及克隆

以斜带石斑鱼囊胚期胚胎和尾芽期胚胎分别作为检验组和驱动组,构建了石斑鱼囊胚期胚胎和尾芽期胚胎的抑制性差减杂交cDNA文库。以α-tubulin作为检测指标,显示差减效率分别高达28和27。分别取囊胚期胚胎和尾芽期胚胎各192和960个PCR阳性克隆进行斑点杂交,得到15个囊胚期和131个尾芽期的斑点杂交阳性克隆。测序和数据库比对分析表明,囊胚期15个阳性克隆中有11个已知基因的cDNA片段和没有同源性的4个cDNA片段;而在尾芽期的131个阳性克隆中,有123个已知基因的cDNA片段和8个没有同源性的cD-NA片段。用半定量RT-PCR技术分析了部分基因片段在胚胎发育过程中的表达规律和和组织分布情况。这些差异表达片段的呈现为进一步揭示石斑鱼胚胎发育、早期性别决定和性腺分化的分子机制奠定了基础。     

Phenology of the red mangrove, Rhizophora mangle L., in the Caeté Estuary,Pará, equatorial Brazil

The current study presents phenology data for Rhizophora mangle from two equatorial mangrove stands with different salinity regimes in Brazil. Observations based on litter fall and individual shoot development were compared and related to environmental factors. Patterns observed in litter fall were consistent with results of direct monitoring. While both reproductive organs and leaves were produced throughout the year, rates of formation followed seasonal trends. Distinct differences in propagule production between low and high salinity sites and between years of observation were detected; main propagule release was, however, restricted to the wet season which offers enhanced conditions for propagule establishment. Emergence of flowers was linked to leaf production. While there was no obvious single peak in leaf production, it was reduced towards the end of the dry season at both high and low salinity sites. Time series analysis revealed an independent pattern of leaf development superimposed on this annual seasonal trend, indicating slower development of leaf primordia during periods of low light availability in the wet season. No significant difference in age structure was detected between sun and shade leaves; maximum leaf life-time was approximately 1 year.     

Chitosan as a growth stimulator in orchid tissue culture

The effect of shrimp and fungal chitosan on the growth and development of orchid plant meristemic tissue in culture was investigated in liquid and on solid medium. The growth of meristem explants into protocorm-like bodies in liquid medium was accelerated up to 15 times in the presence of chitosan oligomer, the optimal concentration being 15 ppm. The 1 kDa shrimp oligomer was slightly more effective compared to 10 kDa shrimp chitosan and four times more active compared to high molecular weight 100 kDa shrimp chitosan. The 10 kDa fungal chitosan was more effective compared with 1 kDa oligomer. The development of orchid protocorm into differentiated orchid tissue with primary shoots and roots was studied on solid agar medium. The optimal effect, the generation of 5–7 plantlets in 12 weeks was observed in the presence of 20 ppm using either 10 kDa fungal or 1 kDa oligomer shrimp chitosan. The data are consistent with preliminary results from field experiments and confirm unequivocally that a minor amount of chitosan has a profound effect on the growth and development of orchid plant tissue.     

Flower colour and cytochromes P450

Flavonoids are major constituents of flower colour. Plants accumulate specific flavonoids and thus every species often exhibits a limited flower colour range. Three cytochromes P450 play critical roles in the flavonoid biosynthetic pathway. Flavonoid 3′-hydroxylase (F3′H, CYP75B) and flavonoid 3′,5′-hydroxylase (F3′5′H, CYP75A) catalyze the hydroxylation of the B-ring of flavonoids and are necessary to biosynthesize cyanidin-(red to magenta) and delphinidin-(violet to blue) based anthocyanins, respectively. Pelargonidin-based anthocyanins (orange to red) are synthesized in their absence. Some species such as roses, carnations and chrysanthemums do not have violet/blue flower colour due to deficiency of F3′5′H. Successful expression of heterologous F3′5′H genes in roses and carnations results in delphinidin production, causing a novel blue/violet flower colour. Down-regulation of F3′H and F3′5′H genes has yielded orange petunia and pink torenia colour that accumulate pelargonidin-based anthocyanins. Flavone synthase II (CYP93B) catalyzes the synthesis of flavones that contribute to the bluing of flower colour, and modulation of FNSII gene expression in petunia and tobacco changes their flower colour. Extensive engineering of the anthocyanin pathway is therefore now possible, and can be expected to enhance the range of flower colours.     

灰杨克隆繁殖、自身养分与土壤养分季节变化及其耦合关系的林缘——林内差异

阐明灰杨(Populus pruinosa Schrenk)克隆特征变化及受外界环境影响,是增强灰杨林生态服务功能的基础。本研究在中国新疆塔里木河上游灰杨河岸林,沿垂直河道方向在林缘(距河道200 m)、林内(距河道400 m)生境设置样方,于2014年4～10月,每隔20天调查两生境不定芽、未出土和出土克隆分株数量,测定横走侧根及土壤养分含量。结果表明:(1)横走侧根全氮、全磷、全钾、有机碳含量的变化趋势与不定芽和未出土分株数在4～6月逐渐增加、7～10月逐渐减少变化趋势基本一致,与土壤有机质、碱解氮、速效磷及速效钾含量在4～6月逐渐升高或保持最高水平,在7～10月逐渐降低的变化趋势同步;横走侧根碳氮比在4～6月初逐渐降低,随后呈现增大又减小的趋势;氮磷比在4～6月逐渐减小,7月显著减小后逐渐增大(林缘)或基本保持不变(林内)。(2)不论是林缘还是林内,不定芽数量受到横走侧根全氮和氮磷比的影响,未出土分株数受到横走侧根全氮、有机碳含量、碳氮比的影响;林缘不定芽数量与土壤有机质、碱解氮及速效钾含量相关紧密,未出土分株数与土壤碱解氮和速效磷显著相关,土壤养分也与横走侧根全氮、碳氮比、氮磷比紧密相关,而在林内受到土壤养分影响的主要是横走侧根全氮和氮磷比。(3)林内的不定芽、未出土及出土克隆分株数量显著低于林缘,土壤养分含量通过影响横走侧根养分含量而影响不定芽、未出土分株、出土分株数量。灰杨是杨属为数不多的国家保护植物,具有重要的生态服务功能,我们的结果对基于克隆繁殖的灰杨林保护策略提供基础数据支持。     

走马胎的组织培养与快速繁殖

以走马胎(Ardisia gigantifolia)幼嫩茎段为外植体, 通过腋芽增殖的方式进行组织培养和快速繁殖研究。结果表明, 培养基MS+1.0 mg·L ^-1 6-BA+0.2 mg·L ^-1NAA和MS+0.5 mg·L ^-1 ZT均可用于腋芽的诱导和前期继代培养, 诱导率分别为89.3%和85.7%; 芽增殖最佳培养基为MS+0.5 mg·L ^-16-BA+0.1 mg·L ^-1ZT+0.1 mg·L ^-1NAA, 增殖系数为4.3倍; 根诱导最佳培养基为1/2MS+1.5 mg·L ^-1 IAA+1.0 mg·L ^-1 NAA, 生根率达92.3%, 且根系发达, 植株健壮; 生根苗在混合基质园土:泥炭:珍珠岩=3:1:1 (v/v/v )中移栽成活率为82%。该研究建立了走马胎种苗的组织培养快速繁殖技术体系, 且可应用于规模化生产。     

莼菜休眠芽解除休眠及生根的研究

莼菜为世界著名珍稀水生蔬菜,具有很高的食用和药用价值。已有研究显示,可通过冬芽实现莼菜复壮,找出休眠解除的最佳方法是复壮的基本前提。本实验以莼菜冬季型休眠芽（冬芽）为实验材料,通过光照、温度等处理探求莼菜冬芽的休眠解除方法。莼菜冬芽生根率随着光照强度的增加,其生根率由全黑暗0%显著增长至（16.0±1.3）%;温度和处理时间对莼菜冬芽生根率、根长、生根根数和含水量有显著性影响。其中,35 °C水浴处理6 h后各项指标均到达较大值,上述指标分别为（96.1±2.8）%、（7.2±0.2） cm、74.5±6.0和（83.6±0.3）%;40 °C（6 h）、45 °C（1、3和6 h）和50 °C（10、20和30 min）水浴处理后莼菜冬芽绝大部分失绿变黄;随着培养时间的延长,其冬芽全部腐烂。光照能够促进莼菜冬芽生根;土培生根效果较为显著;适度水浴加热处理能有效解除莼菜冬芽的休眠,35 °C水浴处理6 h为最佳处理方案。