番木瓜叶片愈伤组织形成、分化及再生植物移栽

研究了番木瓜的叶片愈伤组织的形成,并进一步诱导分化,离体培养成完整的试管植株,这对深入进行体细胞突变育种,以及抗病毒品系筛选和种质改善或耐贮藏等基因转化,提供了有用的技术和方法。     

软枣猕猴桃叶片愈伤组织分化再生植株

1植物名称软枣猕猴桃Q如动九面tyHna）。2材料类别组培苗叶片。3培养条件叶愈伤组织诱导培养基为MS＋ZT2rug·I，’（单位下同）＋NAA0．3。分化培养基有10个：（1）MS＋NAAO．05＋ZT15；（2）加ZTIO，余同培养基（1）；（3）加ZT5，余伺（l）；（4）加ZT2，余同（1）；（5）MS＋NAA01＋ZT15；（6）加ZT10，余同（5）；（7）加ZT5，余同（5）；（8）加ZT2，金同（5）；（9）加ABA1，余同（3）；（10）加ABA0．1，余同（3）。生根培养基为1／2MS＋IBA05。以上培养基中均加入3％蔗糖、肌醇100、0．75％琼脂，PH5so分化培…     

小麦叶片愈伤组织及其再生植株的诱导

小麦幼苗基部外植体在补加２,４－Ｄ的ＭＳ、Ｎ６、ＢＡ１（３）培养基上均可诱导出愈伤组织,２,４－Ｄ的最适浓度为２．０ｍｇ／Ｌ;愈伤组织的增殖速度与切段部位及基本培养基有关,其中在以ＭＳ补加２．０ｍｇ／Ｌ２,４－Ｄ的培养基上诱导出的愈伤组织增长速度最快;最后讨论了小麦愈伤组织幼苗诱导率低的原因及可能解决的方法。     

玉米叶片愈伤组织的诱导及其植株再生

植物名称:玉米(Zea mays)品种小金黄。材料类别:幼叶。培养条件:以MS培养基为基本培养基,生长调节物质配比为:(1)2,4-D 4mg╱L(单位下同) NAA2 IAA2;(2)2,4-D8 NAA4 IAA4;(3)2,4—D 8 NAA4 IAA4 ZT0.5 BA0.5 区T 0.5:(4)2,4-DS NAA4 IAA4 ZTl     

长寿花叶片愈伤组织的诱导和植株再生

１植物名称长寿花（Ｋａｌａｎｃｈｏｅｂｌｏｓｓｆｅｌ－ｄｉａｎａ）。２材料类别叶片。３培养条件培养基：（１）ＭＳ＋２,４－Ｄ１ｍｇ·Ｌ~（－１）（单位下同）＋６－ＢＡ０．１;（２）ＭＳ＋ＮＡＡ１＋６．ＢＡ０．１;（３）ＭＳ＋６－ＢＡ１＋ＮＡＡ０．１;（４）１／２ＭＳ。以上培养基均加蔗糖３０ｇ·Ｌ~（－１）,琼脂８ｇ·Ｌ~（－１）,ｐＨ值为５．８,高压灭菌,培养温度２３～２６℃,光照１２ｈ·ｄ~（－１）,光照度１０００ｌｘ左右。４生长与分化情况４．１无菌材料的获得从实生苗上取下叶片,经自来水冲洗后,用…     

影响籼稻愈伤组织形成和植株再生能力的因素

介绍了一些影响籼稻愈伤组织形成和植株再生的因素及部分因素的作用机理的研究近况，并提出一些可供进一步研究的问题。     

油桐叶片愈伤组织诱导及植株再生

以油桐无菌苗叶片为试材,研究不同种类及浓度的植物生长调节剂对愈伤组织诱导、分化、增殖及生根的影响。结果表明：叶片愈伤组织的最佳诱导培养基为1／2MS＋2．omg·L-16-BA＋1．0mg·L～2,4-D,诱导率达100％;最佳分化培养基为1／2MS＋3．0mg·L～6-BA＋0．1mg·L-1。IBA＋0．05mg·L—IAA,分化率为86．36％;最佳继代增殖培养基MS＋3．0mg·L～6-BA＋0．05mg·L。IBA;最佳生根培养基为1／2MS＋O．1mg·L-1。IBA,生根率93．83％。炼苗后移栽到泥炭土：珍珠岩：蛭石=2：1：1的基质中,成活率达92％以上。     

植物叶片愈伤组织形成的可能机制

分析了植物叶片在组培条件下形成愈伤组织的过程.文中提出,培养基配方中的酸性物质使植物叶片处于酸性环境中并导致植物正常细胞首先发生细胞壁酸性降解,随后出现原生质体脱离细胞壁,进一步发生细胞器重组或细胞重建,人工培养基的酸性环境使细胞壁强制性地降解后,植物原生质体失去细胞壁的包被后直接处于较酸性的环境中,可能会促使原生体出现酸性快速分裂.因此,植物细胞壁是控制植物细胞完成正常细胞周期的信号载体.     

红肉小果型番木瓜品种'美中红'体胚的诱导

用红肉小果型番木瓜品种‘美中红’为外植体,探讨不同成熟度的幼胚、不同浓度2,4-D和培养条件对其体胚的诱导以及体胚形成过程的结果表明:以子叶和内外种皮都为白色且个体较大的番木瓜幼胚(90~120d)在含10mg·L-12,4-D的培养基中和黑暗条件下诱导愈伤组织的效果最佳,愈伤组织的诱导率随着2,4-D浓度的增加而增加。番木瓜愈伤组织最先发生于形态学上的胚根下端,体胚多发生于形态学上的胚芽上端。     

海边香豌豆胚性愈伤组织的诱导和体细胞胚发生

将生长１４ｄ的海边香豌豆（Ｌａｔｈｙｒｕｓ ｍａｒｉｔｉｍｕｓ（Ｌ．）Ｂｉｇｅｌ）无菌苗下胚轴切成０．５ｃｍ左右的片段,置于含有１ｍｇ／Ｌ２,４－Ｄ,０．５ｍｇ／Ｌ ＢＡ和０．５％ＮａＣｌ的ＭＳ培养基中,２８ｄ后诱导出胚性愈伤组织。将其转入含有适当浓度２,４－Ｄ的ＭＳ培养基上,又２８ｄ后可得到大量球形胚和心形胚以及极少量鱼雷胚和子叶胚。诱导体细胞胚适合的２,４－Ｄ浓度为０．５ｍｇ／Ｌ。较高浓度的２     

Association of some plant defense enzyme activities with systemic resistance to early leaf blight and leaf spot induced in tomato plants by azoxystrobin and Pseudomonas fluorescens

Abstract

Azoxystrobin at three different concentrations, namely, 31.25, 62.50 and 125 g a.i. ha^?1 mancozeb (1 kg ha^?1) and Pseudomonas fluorescens (10 kg ha^?1) were evaluated for their efficacy in inducing defense enzymes in tomato against Alternaria solani and Septoria lycopersici. The activity of defense enzymes peroxidase (PO), polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL), β-1, 3 glucanase, chitinase, catalase and defense-inducing chemicals (total phenols) was found to be increased in azoxystrobin and P. fluorescens-treated tomato plants. The activity of these defense enzymes and chemicals was higher in azoxystrobin (125 g a.i. ha^?1) and P. fluorescens-treated tomato plants challenge inoculated with the pathogens compared to other treatments. Increased expression of specific isoforms of PO and PPO was also observed due to ISR induction.     

Roles of the fructans from leaf sheaths and from the elongating leaf bases in the regrowth following defoliation of Lolium perenne L

The study of carbohydrate metabolism in perennial ryegrass (Lolium perenne L. cv. Bravo) during the first 48 h of regrowth showed that fructans from elongating leaf bases were hydrolysed first whereas fructans in mature leaf sheaths were degraded only after a lag of 1.5 h. In elongating leaf bases, the decline in fructan content occurred not only in the differentiation zone (30–60 mm from the leaf base), but also in the growth zone. Unlike other soluble carbohydrates, the net deposition rate of fructose remained positive and even rose during the first day following defoliation. The activity of fructan exohydrolase (FEH; EC 3.2.1.80) was maximal in the differentiation zone before defoliation and increased in all segments, but peaked in the growth zone after defoliation. These data strongly indicate that fructans stored in the leaf growth zone were hydrolysed and recycled in that zone to sustain the refoliation immediately after defoliation. Despite the depletion of carbohydrates, leaves of defoliated plants elongated at a significantly higher rate than those of undefoliated plants, during the first 10 h of regrowth. This can be partly attributed to the transient increase in water and nitrate deposition rate. The results are discussed in relation to defoliation tolerance. Received: 16 June 2000 / Accepted: 17 October 2000     

The possible influence of L-histidine on the origin of the first peptides on the primordial Earth

One of the most unsettled problems of prebiotic evolution and the origin of life is the explanation why one enantiomeric form of biomolecules prevailed. In the experiments presented in this paper, the influence of L-histidine on the peptide formation in the Salt-Induced Peptide Formation (SIPF) reaction of the enantiomeric forms of valine, proline, serine, lysine, and tryptophan, and the catalytic effects in this first step toward the first building blocks of proteins on the primordial earth were investigated. In the majority of the produced dipeptides, a remarkable increase of yields was shown, and the preference of the L-amino acids in the peptide formation in most cases cannot be denied. In summary, our data provide further experimental evidence for the plausibility of the SIPF reaction and point at a possible important role of L-histidine in the chemical evolution on the primordial Earth.     

新疆植被生产力与叶面积指数的变化及其对气候的响应

利用美国探路者卫星遥感资料AVHRR LAI和全球生态模式CASA给出的植被净初级生产力资料(NPP)对新疆地区1982~2000年的植被时空变化进行了定量分析,结果表明新疆地区的LAI和NPP的空间分布严格受水分的制约,与气温呈负相关,表现出干旱内陆地区植被受降水控制的地带特征。相对于20世纪80年代,90年代整个新疆出现了变暖的趋势,降水基本也呈现增加的趋势,在42°N以北地区暖湿转型尤其明显,与这种气候型相对应,植被出现了明显的增加趋势,NPP最大增幅可达45gCm-2a-1。但植被对气温和降水的年际变化响应不一样,降水主要是影响植被峰值的起落,而植被在总体演变趋势上却主要受气温控制,3个分区1984~2000年的气温明显上升,而降水变化趋势不明显,植被受气温控制出现了显著的上升趋势(P<0.01)。     

The formation of the right and left heart ventricles from the ventricular part of the cardiac tube during embryogenesis

It has been generally assumed that the initial rudiment of the heart ventricle is divided by the longitudinal interventricular septum into the right and left ventricles. This paper presents evidence for the hypothesis that the right and the left ventricles are produced during normal development from different sequentially located segments of the cardiac tube. These segments yielding rudiments of the right and left ventricles could be detected even during early embryogenesis. This hypothesis requires a new explanation for the process of the formation of two separate outlets from the heart ventricles.     

Accumulation of interspersed and sex-specific repeats in the non-recombining region of papaya sex chromosomes

Background

The papaya Y chromosome has undergone a degenerative expansion from its ancestral autosome, as a consequence of recombination suppression in the sex determining region of the sex chromosomes. The non-recombining feature led to the accumulation of repetitive sequences in the male- or hermaphrodite-specific regions of the Y or the Y^h chromosome (MSY or HSY). Therefore, repeat composition and distribution in the sex determining region of papaya sex chromosomes would be informative to understand how these repetitive sequences might be involved in the early stages of sex chromosome evolution.

Results

Detailed composition of interspersed, sex-specific, and tandem repeats was analyzed from 8.1 megabases (Mb) HSY and 5.3 Mb corresponding X chromosomal regions. Approximately 77% of the HSY and 64% of the corresponding X region were occupied by repetitive sequences. Ty3-gypsy retrotransposons were the most abundant interspersed repeats in both regions. Comparative analysis of repetitive sequences between the sex determining region of papaya X chromosome and orthologous autosomal sequences of Vasconcellea monoica, a close relative of papaya lacking sex chromosomes, revealed distinctive differences in the accumulation of Ty3-Gypsy, suggesting that the evolution of the papaya sex determining region may accompany Ty3-Gypsy element accumulation. In total, 21 sex-specific repeats were identified from the sex determining region; 20 from the HSY and one from the X. Interestingly, most HSY-specific repeats were detected in two regions where the HSY expansion occurred, suggesting that the HSY expansion may result in the accumulation of sex-specific repeats or that HSY-specific repeats might play an important role in the HSY expansion. The analysis of simple sequence repeats (SSRs) revealed that longer SSRs were less abundant in the papaya sex determining region than the other chromosomal regions.

Conclusion

Major repetitive elements were Ty3-gypsy retrotransposons in both the HSY and the corresponding X. Accumulation of Ty3-Gypsy retrotransposons in the sex determining region of papaya X chromosome was significantly higher than that in the corresponding region of V. monoica, suggesting that Ty3-Gypsy could be crucial for the expansion and evolution of the sex determining region in papaya. Most sex-specific repeats were located in the two HSY expansion regions.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-335) contains supplementary material, which is available to authorized users.