Dormancy in Garlic (Allium sativum L.) cv. Rosado Paraguayo II. The Onset of the Process during Plant Ontogeny

Dormancy in garlic cv. Rosado Paraguayo was studied during plantontogeny in relation to endogenous growth regulators and bulb-forming.The differentiation of seed cloves began coincidently with abulb-forming rate of 0.47 and a lack of gibberellin and moderateinhibitor activities. This hormone levels remained at harvest,when the seed cloves, which had completed their final size,were unable to sprout. Considering these and previous results,the lack of gibberellin like promoters could be the main factorwhich controls dormancy in garlic. (Received May 7, 1985; Accepted November 26, 1985)     

大蒜体细胞胚胎发生研究进展

大蒜生产主要靠无性繁殖 ,因此 ,进行大蒜体细胞胚发育研究具有重要意义。本文对大蒜体细胞胚发育的影响因子进行了综述 ,其中较高浓度的维生素B1 及还原态氮源可能有利于胚胎发生 ,而大蒜体细胞内含物则不利于胚胎发生。此外 ,对大蒜体细胞胚培养中存在的主要问题进行了讨论 ,并认为系统开展体细胞胚发生的细胞分子生物学机理研究、建立悬浮培养体系以及进行大蒜体细胞胚无性系变异的研究等 ,具有广阔的前景。     

大蒜辣素UPLC检测体系优化及其在大蒜资源评价中的应用

大蒜是重要的调味蔬菜,大蒜辣素的含量是评价大蒜品质的最重要的一项指标.本研究通过对样品处理、提取方法和检测方法的研究,建立了完善的大蒜辣素超高效液相色谱(UPLC)检测方法:使用UPLC BEH C18色谱柱,流动相为甲醇∶水=1∶1,检测波长为254nm,进样体积为1μl,流速为0.3ml/min.大蒜辣素在2.04 ～ 510mg/L范围内呈良好线性关系(R2 =0.9991).利用建立的方法对212份大蒜鳞茎的大蒜辣素含量进行检测,发现供试212份大蒜资源的大蒜辣素含量差异显著,含量分布在0.82％ ～3.01％之间,最高含量与最低含量之间相差近4倍.     

光暗条件下大蒜DNA甲基化差异的初步研究

用甲基敏感扩增多态性(MSAP)技术分析光暗条件下生长的大蒜DNA甲基化水平差异。结果表明,用8对引物组合扩增出343条带,完全一致的带型240条,不一致的103条。在不一致的条带中,光照条件下相同的47条带与黑暗条件下相同的带型有差异,与黑暗相比光照下出现的去甲基化带28条,有56条差异带在2个处理内个体间也有差异。总的趋势是光照引起大蒜DNA去甲基化。     

大蒜化学成分的气-质联用分析

本文采用环己烷、乙酸乙酯和正丁醇对大蒜（Allium sativum L.）新鲜鳞茎的95%乙醇提取物进行萃取,并与水蒸气蒸馏法提取的挥发油成分进行比较,用GC-MS对其成分进行定性和定量分析.在环己烷萃取物中共检出112个成分,鉴定了38个化合物,占环己烷萃取物总量的80.08%;在乙酸乙酯萃取物中检出86个成分,鉴定了26个化合物,占乙酸乙酯萃取物总量的56.70%;在正丁醇萃取物中未检出挥发性成分.在水蒸气蒸馏法提取的挥发油中共检出109个成分,鉴定了29个化合物,占挥发油总量的83.58%.大蒜95%乙醇提取物的环己烷和乙酸乙酯萃取物及大蒜挥发油中皆以含硫化合物为主.在环己烷和乙酸乙酯萃取物中,阿霍烯的含量分别为生药的0.00395%和0.00145%,大蒜中阿霍烯含量达0.00540%.     

气体NO处理对蒜苗生长和抗氧化酶活性的影响

以改良的蒜为材料,用不同浓度NO气体（0．1、0．5、1．0μmol·L^-1）在无氧环境中熏蒸大蒜3h后,检测蒜苗生长、光合色素和可溶性蛋白质含量以及抗氧化酶活性的结果表明：0．1和0．5μmol·L^-1NO气体熏蒸的蒜种长成的幼苗,叶中光合色素和可溶性蛋白含量、假茎长、株高和假茎粗均大于未经NO熏蒸的植株,叶中超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）的活性均提高;而1．0μmol·L^-1的NO则抑制蒜苗生长,且抗氧化酶活性亦下降。气态NO处理的鳞茎幼苗生长也得到促进,以0．5μmol·L^-1NO处理的效果最佳。     

Flavor formation in tissue cultures of garlic (Allium sativum L.)

Differentiated and undifferentiated cultures of garlic (Allium sativum L.) were analyzed for the study of flavor formation in cultures. Attempts were made to correlate alliin content with free and bound amino acid contents and with enzymes like phenylanine ammonialyase (E.C. 4.1.1.5) and alliin-lyase (E.C.4.4.1.4) which play important roles in formation of the flavor percursor alliin.It was observed that in differentiating cultures showing shoot formation, there is an increase in alliin content as well as in free and bound amino acid contents. Corresponding to this there was also an increase in the activity of phenylalanine ammonialyase in differentiating cultures. Alliin-lyase activity was found to be significantly different in differentiating and undifferentiated cultures. The significance of these results is discussed.     

Effect of Seed Damage on Growth and Development in Pea (Pisum sativum L.) and Wheat (Triticum aestivum L.)

The effect of damage to the food storage of the seed on theensuing plant was compared in cultivars of two species differingin seed structure, the Greenfeast pea with cotyledons and theGabo wheat with endosperm. Partial removal of storage tissue slightly retarded growth ratein both species and slowed development rate in wheat. Completeremoval lowered the germination rate, drastically slowed thegrowth rate of the survivors for the first 20 d after sowingand lowered the development rate throughout the life cycle. This treatment doubled the time to flower initiation (20 d later)compared with the control, thus indicating the promotive roleof both cotyledon and endosperm in the progress of the shoottowards the reproductive state. The number of vegetative nodes in the pea was lowered by twonodes whereas it was raised by one in the wheat.     

Role of garlic (Allium sativum L.) in human and plant diseases

A resurgence of interest in garlic due to recent revelations of its beneficial effects in the treatment of various human and plant diseases and also due to validation of claims made in traditional systems of medicine has resulted a plethora of publications on different aspects of garlic in recent years. Chemical constituents of garlic and their variations on the methods of isolation have been discussed in the present review. Effect of garlic and its constituents against various human and plant pathogenic and saprophytic microorganisms has also been reviewed.     

Seed quality effects in bulb onions (Allium cepa L.)

The nature and persistence of seed quality effects produced by a range of seed production treatments was investigated in the autumn-sown onion crop. Genotypically equivalent seed lots raised in different glasshouses within the same year were found to germinate at significantly different rates. The seed lot which emerged earlier produced larger seedlings and this difference in size persisted throughout the growing period. In a comparison between the effects of hand crossing and self-pollination techniques the hand crossing method produced a much lower total seed yield but heavier seeds and larger plants. The induced effects persisted throughout the year but were not significant in the mature bulb characters. The implications of these results upon the control of seed production for plant breeding and genetical experiments is discussed.     

Genetic variability in callus formation and regeneration of garlic (Allium sativum L.)

Twenty garlic Allium sativum (L.) genotypes were analysed for genetic variation in their ability to form callus (in one medium) and regenerate shoots (in four different media). Genotypes showed significant differences in the analysis of variance of all the traits tested. The accession Printanor showed the best general behaviour, with 83% callus-producing explants, 44.7% organogenic explants, and 15.35 shoots/g of callus. The best regeneration medium was MBO, without growth regulators. Shoot production capacity was examined with the additive main effects and multiplicative interaction model that proved to be a powerful tool for analysis and easy comprehension of the strong genotype×medium interactions frequently observed in in vitro culture systems. Received: 5 February 1998 / Revision received: 11 May 1998 / Accepted: 1 June 1998     

Intercropping of Green Garlic (Allium sativum L.) Induces Nutrient Concentration Changes in the Soil and Plants in Continuously Cropped Cucumber (Cucumis sativus L.) in a Plastic Tunnel

A pot-based experiment was conducted to investigate nutrient concentrations in cucumber plants intercropped with various amounts of green garlic. In addition, the soil nutrient contents were studied over two consecutive growing seasons. The results revealed that the accumulation of biomass and the nutritional elements nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and manganese (Mn) in cucumber plants were significantly increased for intercropping treatments during the two growing seasons compared to monoculture. Conversely, magnesium (Mg) concentrations were decreased in the cucumber plants. Shoot iron (Fe) concentrations decreased whereas root Fe concentrations increased in the intercropping system. Shoot and root zinc (Zn) concentrations decreased during the fall of 2011 but increased during the spring of 2012. Soil organic matter and available N, P and K were significantly increased as the proportion of intercropped green garlic increasing. Medium levels of intercropping green garlic improved cucumber nutrient concentrations the most. The regression analysis showed that the concentrations of most elements were significantly related to the amounts of garlic bulbs, especially the microelements in the spring 2011. The available soil N and organic matter were linearly related to the amounts of garlic bulbs. The results indicate that the nutritional status of the soil and plants of continuously cropped cucumber could be improved by intercropping with green garlic.     

The influence of 2,4-dichlorophenoxyacetic acid on cell cycle Kinetics and Sister-Chromatid Exchange Frequency in Garlic (Allium sativum L.) Meristem Cells

The effect of 2,4-dichlorophenoxyacetic acid (2,4-D) at low concentrations on cell cycle duration and sister-chromatid exchange (SCE) frequency was studied using meristem root-tip cells ofAllium sativum L. 2,4-D induced a marked prolongation of the cell cycle. At the same time, small but statistically significant increases in SCE frequencies were observed at 5 μM and 15 μM 2,4-D concentrations. The significance of these findings in the evaluation of mutagenic activity of 2,4-D is discussed.     

Relationships between peroxidases and in vitro bulbification in garlic (Allium sativum L.)

Summary The relationship between in vitro bulbification and peroxidase activities of garlic (Allium sativum L.) was studied. Two stages could be distinguished during in vitro bulb formation characterized by the peroxidase activity, isoenzymatic patterns especially of the soluble fractions, dry weight, and bulbification index (BI). The first stage, called the morphogenic stage, started after planting until 30d of culture with a maximum soluble peroxidase activity, BI=1–0.5 and low dry weight. At that time axillary buds preformed at the base of the leaves grew and the in vitro bulb was generated. The second stage (filling in and bulb maturation) started when the BI reached 0.5 at 30 d of the ontogenic cycle, as a result of the bulb assimilate accumulation phenomenon. During the morphogenic stage the soluble peroxidase activity was maximum and the zymograms showed higher intensity bands. The second stage presented anodic ionic peroxidases and substantial increase in staining of the anodic covalent peroxidase fraction. The putative role of the different isoforms of peroxidases in relation to the bulbification process is discussed.     

Transformation and regeneration of garlic (Allium sativum L.) by Agrobacterium-mediated gene transfer

 By using highly regenerative calluses, we developed a stable transformation system in garlic (Allium sativum L.). The temperature and number of days of co-cultivation with Agrobacterium tumefaciens was shown to be an important factor in transient expression of the uid A gene. After a culture period of 5 months in selection medium containing hygromycin, 20 shoots were induced from ca. 1000 calluses, among which 15 plants expressed β-glucuronidase activity upon staining with X-Gluc. Shoots developed into transgenic garlic after 1 month. Integration of the uid A gene was confirmed by Southern blot analysis for genomic DNA of transgenic garlic plants. Received: 25 October 1999 / Revision received: 16 February 2000 / Accepted: 22 February 2000     

Characterisation of the high-molecular weight fructan isolated from garlic (Allium sativum L.)

A high molecular weight fructan was isolated from garlic and the structure determined by enzymatic, chemical and spectroscopic (NMR) methods. It was found that the garlic fructan belongs to the neokestose family. It has a (2 --> 1)-linked beta-D-Fruf backbone with (2 --> 6)-linked beta-D-Fruf side chains. A structural model was postulated for a degree of polymerisation of about 58. This model was substantiated using an endo-inulinase purified from Aspergillus ficuum and by 1H and 13C NMR spectroscopy.     

Comparative study of the post-translational processing of the mannose-binding lectins in the bulbs of garlic (Allium sativum L.) and ramsons (Allium ursinum L.)

The biosynthesis and processing of the homodimeric and heterodimeric lectins from the bulbs of garlic (Allium sativum) and ramsons (wild garlic;Allium ursinum) were studied using pulse and pulse-chase labelling experiments on developing bulbs. By combining the results of thein vivo biosynthesis studies and the cDNA cloning of the respective lectins, the sequence of events leading from the primary translation products into the mature lectin polypeptides could be reconstructed. From this it is demonstrated that garlic and ramsons use different schemes of post-translational modifications in order to synthesize apparently similar lectins from totally different precursors. Both the homomeric garlic lectin (ASAII) and its homologue in ramsons (AUAII) are synthesized on the endoplasmic reticulum (ER) as nonglycosylated 13.5 kDa precursors, which, after their transport out of the ER are converted into the mature 12.0 kDa lectin polypeptides by the cleavage of a C-terminal peptide. The heterodimeric garlic lectin ASAI is synthesized on the ER as a single glycosylated precursor of 38 kDa, which after its transport out of the ER undergoes a complex processing which gives rise to two mature lectin subunits of 11.5 and 12.5 kDa. In contrast, both subunits of the heterodimeric ramsons lectin AUAI are synthesized separately on the ER as glycosylated precursors, which after their transport out of the ER are deglycosylated and further processed into the mature lectin polypeptides by the cleavage of a C-terminal peptide.     

Generation of chlorsulfuron-resistant transgenic garlic plants (Allium sativum L.) by particle bombardment

We established an effective biolistic transformation procedure fortransferring foreign genes into garlic (Allium sativumL.),which we demonstrated by generating transgenic plants resistant tochlorsulfuron, a sulfonylurea herbicide. We subcultured callus tissue from theapical meristem of garlic cloves and repeatedly selected calli with brittle,non-mucilaginous surfaces for over six months, to increase transformationefficiency. We then constructed recombinant DNA that contained the acetolactatesynthase (ALS) gene from a chlorsulfuron-resistantArabidopsis mutant, the cauliflower mosaic virus 35Spromoter, the -glucuronidase (GUS) reporter gene, and the hygromycinphosphotransferase (HPT) selectable marker gene. The garlic calli werebombarded twice with tungsten particles coated with the DNA constructs. Transformed calliwere efficiently selected by embedding them in solid agar medium containing 50mg l^–1 hygromycin B. Selected propagules wereregenerated into 12 independent plants. We confirmed that the transgenes wereintegrated and expressed in the plants using PCR-Southern and Northern blotanalyses and by -glucuronidase expression assay forGUS. The regenerated plants survived in the presence of 3mg l^–1 chlorsulfuron, demonstrating that theirALS was insensitive to this herbicide. These results illustrate the successfultransformation of foreign genes into garlic plants. The set of proceduresdeveloped in this study is applicable to the generation of transgenic garlicplants with other agronomically beneficial traits. These authors contributed equally to this work     

Receptors of Garlic (Allium sativum) Lectins and Their Role in Insecticidal Action

Garlic (Allium sativum) lectins are promising candidate molecules for the protection against chewing (lepidopteran) as well as sap sucking (homopteran) insect pests. Molecular mechanism of toxicity and interaction of lectins with midgut receptor proteins has been described in many reports. Lectins show its effect right from sensory receptors of mouth parts by disrupting the membrane integrity and food detection ability. Subsequently, enter into the gut lumen and interact with midgut glycosylated proteins like alkaline phosphatase (ALP), aminopeptidase-N (APN), cadherin-like proteins, polycalins, sucrase, symbionin and others. These proteins play critical role in life cycle of insect directly or indirectly. Lectins interfere with the activity of these proteins and causes physiological disorders leading to the death of insects. Lectins further transported across the insect gut, accumulated in various body parts (like haemolymph and ovary) and interact with intracellular proteins like symbionin and cytochrome p450. Binding with cytochrome p450 (which involve in ecdysone synthesis) might interfere in the development of insects, which results in growth retardation and pre-mature death.