Rate of nitrogen application during the growing season alters the response of container-grown rhododendron and azalea to foliar application of urea in the Autumn

Summary

One-year-old rhododendron (Rhododendron ‘H-1 P.J.M’) and azalea (Rhododendron ‘Cannon’s Double’) plants grown at different nitrogen (N) fertilisation rates were used to assess the influence of soil N applications during the growing season, and foliar applications of urea in the Autumn, on N uptake and accumulation, and plant growth in the following Spring. N uptake efficiency declined linearly during the first growing season with an increasing rate of N fertilisation. For both cultivars, foliar urea application in the Autumn significantly increased plant N content without affecting plant size, regardless of plant N status. Leaves of rhododendron accumulated more N than other plant structures. Plants sprayed with foliar urea in the Autumn had more new growth the following Spring than plants receiving no urea, regardless of whether the plants received fertiliser in the Spring. For azalea, N uptake in the Spring was, in general, not affected by applications of urea during the previous year. For rhododendron, urea application in the Autumn decreased N uptake the following Spring. For both cultivars, increasing N availability during the growing season increased the ratio of above-ground to below-ground dry weight. Our results suggest that combining optimum N applications during the growing season with foliar application of urea in the Autumn can improve N uptake efficiency, increase N storage, and optimise growth in Rhododendron.     

Are rhododendron hybrids distinguishable on the basis of morphology and microsatellite polymorphism?

Sequence Tagged Microsatellite Sites (STMSs) and morphological trait markers were used to evaluate 33 rhododendron germplasm for genetic diversity assessment and discrimination power. The average genetic diversity estimates were 0.724 (morphological traits) and 0.174 (STMSs) marker datasets. The Shannon index was higher for morphological traits (1.797) than STMS (0.302). The correlation coefficients obtained by the Mantel matrix correspondence test, which was used to compare the cophenetic matrices for the two markers, showed that estimated values of relationships given for morphological and STMS were not significantly related (p > 0.05). The dataset from STMS, supported by the total probability of identity (1.13 × 10⁻⁹) and total paternity exclusion probability (0.9999), allowed all accessions to be uniquely identified. In summary, STMS marker proved to be an efficient tool in assessing the genetic variability among old broad leaf rhododendron genotypes. The pattern of variation appeared to be consistent, and it can be used for germplasm conservation and management for restoration of historical genetic resources.     

杜鹃褐班病病原菌的分离与鉴定

对杜鹃褐斑病的病原菌进行分离、培养,进行了形态学鉴定,并对其rRNA基因内转录间区(ITS区)进行了克隆测序,与Genbank中已有的有关序列进行了比较,确定其病原菌为Phomopsis sp..     

Growth of Rhododendron cultivars as affected by temperature and light

Summary

The purpose of this study was to investigate the adaptation of four Rhododendron cultivars to contrasting light and temperature conditions. Two evergreen rhododendron cultivars and two deciduous azaleas were grown for 112 d under short day (14 h) and long day (20 h) photoperiods combined with temperatures of 15 and 24°C. Additionally, these cultivars were compared for daylength extension at 24°C/long day under two irradiation treatments (incandescent lamps and fluorescent tubular lamps). The number of flushes of growth increased with increasing photoperiod and temperature in both evergreen cultivars and in R. canadense; azalea #89132 made only one flush in all treatments. In the evergreen cultivars the number of leaves per shoot in the first flush did not differ significantly between treatments, indicating that this character was predetermined by conditions during bud development. The number of leaves in later flushes increased with increasing photoperiod and temperature. The elongation growth of most flushes was also enhanced by longer photoperiod and higher temperature. High irradiation during photoperiodic extension further enhanced the growth. Azalea #89132 made more flower buds under high than low irradiation. The two evergreen cultivars differed in their growth habit. ‘Pohjola’s Daughter’ tended to continue growth in long days or at very high temperatures, and is thus predicted to thrive best in a maritime or semi-maritime cool climate. ‘Helsinki University’ responded to short daylength by ceasing growth regardless of temperature, and could be expected to perform successfully also in continental climates at latitudes around 45° N. R. canadense seemed to do best in a cool climate, but azalea #89132 should in time acclimatize in all kinds of climates within the limits of this study.     

Genetics of bulb colour variation and flavonoids in onion

Onion (Allium cepa L.) is one of the most important vegetable crops due to its diverse culinary and health promoting properties. It is a rich source of dietary phytochemicals such as flavonoids and other antioxidants which enhance the medicinal importance of onion. Onion bulb colour is one of the important quality characters actively targeted in breeding programmes. Onion bulbs with red, white, yellow, golden, pink, chartreuse, etc. colour are available and this variation is due to the mutations in structural and regulatory genes of the flavonoid biosynthesis pathway. The genetics of bulb colour variation is very complex and involves multiple genes and their interactions. Further, these flavonoid compounds and their derivatives play diverse roles in plant development and stress tolerance in plants. Here, we review the biosynthesis of flavonoids, genetics and multiple alleles of genes for onion bulb colour, metabolic engineering, flavonoid in biotic and abiotic stress response and effect of cultural and storage practices on onion flavonoids.     

西藏色季拉山杜鹃花种质资源的初步研究

色季拉山杜鹃花有２５个种及变种，其中７种分布于东坡，３种分布于西坡，４种分布于山顶地带，１１种在东西坡均有分布。其生境类型可分为林缘灌丛型、森林型、高山灌丛型３类，以森林型种类居多，占４８％。其观赏类群可分为香花类、团花类、雅致类和黄花类４群，以香花类和黄花类观赏价值最高，雅致类最易被驯化利用。     

Decreased anthocyanin biosynthesis in grape berries grown under elevated night temperature condition

In grape cultivation, high night temperature generally reduces anthocyanin accumulation in berry skin. To clarify the regulatory mechanism of anthocyanin biosynthesis under the conditions of high night temperatures, we examined flavonoid accumulation, the activities of related enzymes and gene expression in the anthocyanin biosynthetic pathway in grape berries grown under cool and warm night conditions. Anthocyanin accumulation in the skin of berries grown at high night temperatures (30 °C continuous) was reduced as compared to that of berries grown at low night temperatures (30 °C in daytime/15 °C in night time). On the other hand, flavonol levels in the skin of berries were not significantly different between low and high night temperature conditions. High night temperatures also inhibited the gene expression of chalcone synthase (CHS), flavanone 3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR), leucoanthocyanidin dioxygenase (LDOX) and UDP-glucose: flavonoid 3-O-glucosyltransferase (UFGT) at veraison and an increase in UFGT activity after veraison. These results suggest that the inhibition of anthocyanin biosynthesis in grape berries grown under high night temperature condition could be caused by lower expression levels of anthocyanin biosynthetic genes at an early stage of ripening and lower activities of anthocyanin biosynthetic enzymes, particularly UFGT.     

Molecular cloning and functional analysis of a flavanone 3-hydroxylase gene from blueberry

Vaccinium corymbosum (blueberry) is touted as a superfood with numerous health benefits due to its high levels of flavonoids. Flavanone 3-hydroxylase (F3H) is a key regulatory enzyme of the flavonoid pathway. In this study, we cloned the full-length cDNA of F3H (designated VcF3H) from young blueberry leaves using rapid amplification of cDNA ends (RACE). The cDNA contained a 1080-bp open reading frame that encoded a 359-amino acid protein. The deduced VcF3H protein showed high similarities to other plant F3Hs. Conserved amino acid motifs required for ferrous iron binding (HXD) and 2-oxoglutarate binding (RXS) were identified in VcF3H, VcFLS (flavonol synthase), and VcANS (anthocyanidin synthase). Quantitative RT-PCR analysis demonstrated that VcF3H was expressed in all tissues tested, with particularly high expression in young leaves, fruits (pink and blue), and stems. Anthocyanins accumulated mainly in fruits, whereas flavonols were found mainly in leaves and stems. Furthermore, the expression pattern of VcF3H was similar to that of VcCHS, VcDFR, and VcANS in various tissues. Heterologous expression of VcF3H in Arabidopsis thaliana increased the anthocyanin content in leaves, but did not affect the flavonol content. Thus, VcF3H seems to be involved in anthocyanin synthesis in the flavonoid biosynthetic pathway when ectopically expressed in Arabidopsis.     

瓜枝孢弱致病菌诱导黄瓜植保素的积累及抑菌活性

瓜枝孢(Cladosporium cucumernium ) 弱致病菌株2-2A₂诱导黄瓜产生对黄瓜黑星病的抗病性反应。对经2-2A₂诱导后黄瓜叶片中提取的物质进行生物活性试验、硅胶板薄层层析、高效液相色谱分析,证明2-2A₂可以有效诱导黄瓜中类黄酮类植保素的积累。     

Isolation and expression analysis of differentially expressed genes in stem tissue of the Greek lemon cv. Adamopoulou

Lemon (Citrus limon (L.) Burm. f.) is susceptible to mal secco, a serious vascular disease caused by the fungus Phoma tracheiphila (Petri) Kant. and Gik., as well as low temperatures. The greek lemon cultivar Adamopoulou, thought to be derived from the Portuguese cultivar Lisbon, exhibits enhanced resistance to mal secco and cold as opposed to cv. Lisbon. Suppression subtractive hybridization (SSH) was employed for the isolation of differentially expressed genes in lemon stem tissue. A subtractive cDNA library was constructed and a total of 296 clones were sequenced. The obtained sequences were edited, resulting in 56 non-redundant ESTs. Sequence analysis revealed homology to previously identified genes involved in defense mechanisms against biotic and abiotic stresses, as well as sequences with no significant similarity in the GenBank. Selected ESTs were analyzed by real-time PCR for confirmation purposes. This analysis revealed significant expression differences between the two cultivars for genes expressing allantoinase, ultraviolet-B-repressible protein, 4-coumarate:CoA ligase and other proteins that are known to be upregulated under biotic and abiotic stress conditions.     

不同种类老山芹总酚和总黄酮含量及抗氧化能力的初步研究

以红色老山芹、绿色老山芹、混合色老山芹的叶片和叶柄为试材,测定不同种类、不同部位老山芹的总酚、总黄酮含量及抗氧化能力,并分析功能活性与物质成分含量之间的相关性。结果表明:不同种类、不同部位老山芹的总黄酮含量、总酚含量大体上表现差异显著,3种老山芹叶片的总黄酮含量和总酚含量均显著高于叶柄;红色老山芹叶片醇提物的抗氧化能力最强,其次为混合色老山芹叶片,绿色老山芹叶柄最弱;各处理醇提物浓度在一定范围内与DPPH·自由基、OH·自由基、ABTS+自由基的清除能力均呈线性关系,醇提物浓度与抗氧化能力呈正相关;老山芹醇提物的抗氧化能力与叶片、叶柄总酚含量呈显著或极显著正相关,与总黄酮含量的相关性不显著。     

Genetics of resistant to tomato yellow leaf curl virus in tomato

The genetics of resistance to tomato yellow leaf curl virus (TYLCV) were studied in TYLCV-resistant lines developed by crossing wild species of Lycopersicon pimpinellifolium, L. hirsutum and L. peruvianum resistant to TYLCV with susceptible L. esculentum cv. Special Back. Crosses between TYLCV-resistant lines derived from the same wild species produced progenies similar to their parents in their level of resistance. However, progenies from interspecific crosses showed greater resistance than either parent suggesting that the genes for TYLCV resistance contributed by different wild species are probably not the same (non-allelic). The gene action for TYLCV resistance also varied with the source of resistance. Analysis of F₁, F₂ and BC populations for lines derived from L. pimpinellifolium showed that resistance to TYLCV in these lines is a quantitative trait with some dominance.     

我国杜鹃花旅游资源特点及开发初探

在分析杜鹃花旅游资源研究与开发现状的基础上,总结出杜鹃花旅游资源具有无与伦比的观赏特性、多种多样的使用价值、博大精深的文化内涵、花卉之王的花界地位、享誉世界的社会影响等特点,提出了资源保护、文化挖掘、品种创新、品牌打造、产业化发展、宣传促销等开发策略,打造国内外著名的杜鹃花旅游品牌,促进我国杜鹃花旅游的发展.     

枣和酸枣不同器官黄酮含量比较及抗氧化能力分析

为进一步提高枣资源综合开发利用率,以酸枣、过渡(中间)类型和栽培枣共3类种质5个品种为试材,对不同品种不同器官(果实、果皮、果肉、叶片、花、种仁)总黄酮含量及果实黄酮提取液清除羟基自由基(·OH)的能力进行分析测定。结果表明:3类种质的5个品种脆熟期果实的总黄酮含量(以鲜重计)为0.89～3.55 mg/g,平均值为1.94 mg/g;果皮总黄酮含量为4.13～8.21 mg/g,平均值为5.73 mg/g;果肉总黄酮含量为0.17～1.07 mg/g,平均值为0.66 mg/g;花总黄酮含量为3.47～6.90 mg/g,平均值为5.50 mg/g;成熟叶片总黄酮含量为7.01～9.02 mg/g,平均值为7.98 mg/g;种仁总黄酮含量为6.48～14.39 mg/g,平均值为11.43 mg/g。5个品种各器官总黄酮含量的大小顺序为:种仁>叶片>果皮>花>果实>果肉;果实、果肉和叶片中总黄酮含量都是酸枣>中间类型>栽培枣;3类种质脆熟期果实黄酮提取液与·OH清除能力均呈显著正相关。     

Effects of suboptimal low temperatures on plant architecture and flowering in muskmelons Cucumis melo L.

Summary

The effects of suboptimal cold temperatures were investigated in an array of vegetative, reproductive and leaf characters in 34 cultivars, both open pollinated and hybrid, of melons, Cucumis melo. The cultivars were grown in two treatments: (i) a heated greenhouse (T1) that produced temperatures similar to those used in commercial cultivation in winter; and (ii) an unheated greenhouse (T2) that produced significantly lower night-time temperatures than T1. Plants grown in T1 had significantly longer main stems and internode lengths, more nodes and more potassium in their leaves but less leaf biomass than plants grown in T2. Plants from T2 also had more green and yellow leaf colour than plants from T1. Open pollinated cultivars had significantly longer main stems, more nodes and more green and yellow leaf colour than hybrid cultivars. Significant differences were found among the cultivars in all traits.     

套袋对新世纪番石榴果皮色素及酚类物质的影响

研究了番石榴(PsidiumguajavaL.)新世纪品种果皮叶绿素、类胡萝卜素、类黄酮和花青苷等色素及总酚的变化动态以及套袋的影响。结果发现,花青苷在果实色泽发育中的作用很小;叶绿素、类胡萝卜素的降解与果实成熟同时发生,二者的综合表现决定果实的色泽;套袋明显抑制了果皮叶绿素、类胡萝卜素和类黄酮的合成,提高了果皮总酚含量。建议果实在采收及贮运过程中不要除袋,以进一步提高其商品性。     

低温胁迫下佛手半致死温度测定和抗寒性分析

 以‘青皮’和‘矮化’佛手(Citrus medica var. sarcodactylis Swingle)为试材,测定不同低温下处理24 h后,叶片的电解质外渗率(REC),计算半致死温度(LT₅₀);在半致死温度下设置不同处理时间,测定REC、超氧化歧化酶(SOD)活性、游离脯氨酸(Pro)和丙二醛(MDA)含量,进行抗寒性分析。结果表明：佛手REC随温度降低及处理时间延长呈“S”形上升, LT₅₀在-4~ -5℃之间;在LT₅₀下,随着处理时间的延长SOD活性呈先上升后下降的趋势, Pro和MDA含量逐渐上升;12~ 24 h为佛手在LT₅₀下冷害发生的临界时间。     

Effect of gibberellic acid on seedling growth in two wild species of pistachio

Summary

Beneh (Pistacia mutica F. & M.) and kolkhong (Pistacia khinjuk Stock) are wild species of pistachio which grow naturally with other trees in some parts of Iran. Because of their adaptibility to severe environmental conditions and their resistance to some pests and diseases, they can be used as rootstocks for pistachio cultivars. Poor germination and very low seedling vigour of these two species have been a major problem in using them as rootstocks for pistachio cultivars. In this study gibberellic acid (GA₃), at five concentrations (100, 250, 500, 750 and 1000 mg l²¹), were used during and after stratification to enhance seedling growth. The results showed that GA₃, applied during and after stratification, significantly increased the length, trunk diameter, internode length, leaf area and fresh and dry weight of seedlings of both beneh and kolkhong species. However, application of GA₃ after stratification was more effective on seedling growth of beneh. GA₃ applied at higher concentrations (500 and 750 mg l²¹) increased the rate of growth, but growth malformations were clearly evident in seedlings of kolkhong. GA₃ at 250 mg l²¹ enhanced seedlings growth of kolkhong. It was concluded that application of GA₃ to the seedlings might be a useful method for promoting rapid shoot growth of beneh and kolkhong and reduce the expense of seedling production in glasshouse conditions.     

Integrating soil solarization with grafting on resistant rootstocks for management of soil-borne pathogens of eggplant

Summary

Soil solarization and grafting onto a resistant tomato rootstock (‘Brigeor F1‘), and the integrated use of both methods were evaluated in four field trials carried out in Cyprus, for management of soil-borne pathogens and pests of eggplant. Soil solarization was highly effective against Verticillium wilt (V. dahliae) but only partially effective against corky root rot (Pyrenochaeta lycopersici) and root-knot nematodes (Meloidogyne spp.); it also controlled adequately most annual weeds. By contrast, grafting provided complete protection from corky root rot and root-knot, but only partial protection from Verticillium wilt. Complete resistance to nematodes, however, occurred only in trials with greenhouse-grown (winter) crops. In open-field (summer) crops, about 50% of the grafted plants sustained slight nematode infection, apparently because of breakdown of resistance at high soil temperatures. Solarization, or grafting gave significant yield increases over that of the untreated check. However, a combination of both was much more effective than either alone. Together, they provided complete protection from all three diseases. Most importantly, they had an additive effect on yield, resulting in a significant increase over that obtained by either method alone. The average yield (kg plant-1) obtained in two greenhouse trials was 9002E5 for the control, 16.1 for grafting alone, 14.1 for solarization alone and 20.2 for the combination of the two methods. The integrated use of solarization and grafting appears to be a sustainable alternative to methyl bromide fumigation.