6-BA、NAA和2,4-D不同配比对荠菜愈伤组织诱导、生长及植株再生的影响

以野生荠菜[Capsella bursa-pastoris （L.） Medic]无菌苗为试材,选取下胚轴、子叶、真叶和叶柄作为外植体,研究了不同外植体的出愈情况,不同植物生长调节剂及配比对愈伤组织诱导、继代及植株再生的影响。结果表明：（1）下胚轴作为外植体出愈情况最好,继代后生长快;（2）下胚轴愈伤组织的最适植株再生培养基为MS＋2～3mg·L-16-BA＋0.2~0.6mg·L-1NAA;（3）愈伤组织培养阶段的2,4-D浓度对其植株再生能力有影响。     

野生口蘑菌种分离及人工驯化

为了给口蘑人工驯化栽培提供依据,开展了口蘑的碳、氮源营养研究。结果表明,蔗糖和牛肉膏分别为最佳碳源和最佳氮源。经转管纯化及在不同培养基驯化培养,该菌株在PSA培养基上,生长速度快、菌丝变得较浓密。但和双孢菇的菌丝相比,无论在麦粒上还是熟料上,菌丝不够粗壮,距离出菇仍然有一定的差距。口蘑的驯化栽培难度较大,欲获得实质性的突破还在于掌握其生长规律及生态习性。温度因子是影响蒙古口蘑菌丝及子实体正常生长发育的关键因子,作为长期适应低温生态环境的结果,适当温度的摸索将是驯化栽培的关键技术。口蘑具有严格的营养要求,因而培养基的筛选至关重要。     

The role of pectin in plant morphogenesis

The presence of a polysaccharidic cell wall distinguishes plant cells from animal cells and is responsible for fundamental mechanistic differences in organ development between the two kingdoms. Due to the presence of this wall, plant cells are unable to crawl and contract. On the other hand, plant cell size can increase by several orders of magnitude and cell shape can change from a simple polyhedron or cube to extremely intricate. This expansive cellular growth is regulated by the interaction between the cell wall and the intracellular turgor pressure. One of the principal cell wall components involved in temporal and spatial regulation of the growth process is pectin. Through biochemical changes to pectin composition and biochemical configuration, the properties of this material can be altered to trigger specific developmental processes. Here, the roles of pectin in three systems displaying rapid growth - the elongation zone of the root, the tip region of the pollen tube, and organ primordia formation at the shoot apical meristem - are reviewed.     

Pollination function transferred: modified tepals of Albuca (Hyacinthaceae) serve as secondary stigmas

Background and Aims

The stigma, a structure which serves as a site for pollen receipt and germination, has been assumed to have evolved once, as a modification of carpels, in early angiosperms. Here it is shown that a functional stigma has evolved secondarily from modified tepals in some Albuca species (Hyacinthaceae).

Methods

Deposition of pollen on Albuca floral organs by bees was recorded. Pollen germination and fruit set was measured in flowers that had pollen deposited solely on their tepals or had their tepal tips experimentally isolated or removed after pollination.

Key Results

Leafcutter bees deposit pollen onto the papillate apices of the inner tepals of Albuca flowers. Pollen germinates in tepal-derived fluid secreted 2 or 3 d after anthesis and pollen tubes subsequently penetrate the style during flower wilting. Application of cross-pollen to the inner tepal apices of A. setosa flowers led to high fruit set. No fruits were produced in pollinated flowers in which the inner tepals were mechanically isolated or removed.

Conclusions

Pollen capture by tepals in the Albuca clade probably evolved in response to selection for floral morphology that maximizes the accuracy of pollen transfer. These findings show how pollination function can be transferred among floral organs, and shed light on how the original angiosperm stigma developed from sporophylls.     

Low concentration of LatB dramatically changes the microtubule organization and the timing of vegetative nucleus/generative cell entrance in tobacco pollen tubes

Low concentration of LatB inhibits not only the actin polymerization, but also induces profound alteration of MT distribution in pollen tubes of Nicotiana tabacum. The short randomly oriented MTs in the apical and subapical regions, became organized as bundles forming subapical rings or basket-like structures, surrounding the apex. Moreover, the depolymerization of AFs in the cortical regions of the apex and subapical region affects the timing of entrance of the vegetative nucleus and generative cell into the pollen tube.     

Medications used to treat nausea and vomiting of pregnancy and the risk of selected birth defects

BACKGROUND Nausea and vomiting of pregnancy (NVP) occurs in up to 80% of pregnant women, but its association with birth outcomes is not clear. Several medications are used for the treatment of NVP; however, data are limited on their possible associations with birth defects. METHODS Using data from the National Birth Defects Prevention Study (NBDPS)—a multi‐site, population‐based, case‐control study—we examined whether NVP or its treatment was associated with the most common noncardiac defects in the NBDPS (nonsyndromic cleft lip with or without cleft palate [CL/P], cleft palate alone [CP], neural tube defects, and hypospadias) compared with randomly selected nonmalformed live births. RESULTS Among the 4524 cases and 5859 controls included in this study, 67.1% reported first‐trimester NVP, and 15.4% of them reported using at least one agent for NVP. Nausea and vomiting of pregnancy was not associated with CP or neural tube defects, but modest risk reductions were observed for CL/P (adjusted odds ratio [aOR] = 0.87; 95% confidence interval [CI], 0.77–0.98) and hypospadias (aOR = 0.84; 95% CI, 0.72–0.98). Regarding treatments for NVP in the first trimester, the following adjusted associations were observed with an increased risk: proton pump inhibitors and hypospadias (aOR = 4.36; 95% CI, 1.21–15.81), steroids and hypospadias (aOR = 2.87; 95% CI, 1.03–7.97), and ondansetron and CP (aOR = 2.37; 95% CI, 1.18–4.76), whereas antacids were associated with a reduced risk for CL/P (aOR = 0.58; 95% CI, 0.38–0.89). CONCLUSIONS NVP was not observed to be associated with an increased risk of birth defects; however, possible risks related to three treatments (i.e., proton pump inhibitors, steroids and ondansetron), which could be chance findings, warrant further investigation. Birth Defects Research (Part A) 2012. © 2011 Wiley Periodicals, Inc.     

Genetic studies of the cystathionine beta-synthase gene and myelomeningocele

BACKGROUND: Among infants born with spina bifida, the most common defect is myelomeningocele (MM). The prevention of MM by maternal periconceptional folic acid (FA) supplementation has been studied extensively. The protective effect provided by FA suggests that the genes involved in folate metabolism, such as cystathionine beta‐synthase (CBS), warrant further investigation. METHODS: This study sequenced the DNA from 96 patients with MM to identify novel potential disease‐causing variants across the 17 exons of the CBS gene. The frequencies of known single nucleotide polymorphisms (SNPs) were identified, and sequences that differed from the reference sequences were considered novel variants. Statistical analysis was performed using two‐sided Fisher's exact test to compare frequencies of SNPs between groups of patients and the known population frequencies. RESULTS: We found a new variant in exon 3 in one patient that results in a G/A change subsequently encoding a stop codon. In addition, we found a new variant in the 3′‐UTR of exon 17. Allele frequencies for 10 known single nucleotide polymorphisms (SNPs) were determined: rs234706, rs72058776, rs1801181, rs6582281, rs71872941, rs12613, rs706208, rs706209, rs73906420, and rs9982921. Of the remaining 48 known SNPs, all tested DNAs were homozygous for the major allele. CONCLUSION: We identified a previously undescribed variant in exon 3 that encodes a stop codon, thus halting downstream translation of the CBS protein. According to the Human Splicing Finder, the 3′‐UTR variant found in exon 17 is predicted to abolish the recognition sites for two splice binding factors, SRp40 and SF2/ASF. The functional significance of the 3′‐UTR mutation needs to be investigated. Birth Defects Research (Part A), 2012. © 2011 Wiley Periodicals, Inc.     

提高大岩桐试管苗移栽成活率的实验

取芽或茎尖经HgCl消毒后获得无菌外植体，将其接种于不同组合的培养基上并获得小植株，将小植株进行继代、生根培养，经炼苗后移栽，成活率很高。