Allelopathy in Agroecosystems in Spain

Summary

This paper reviews the effects of allelopathic interactions in agroecosystems in Spain on plant physiological activity and their ecological advantages. The phenological stage of growth of donor plants and the effective allelochemicals in the soil solution while studying the role of phenolic compounds were highlighting. Finally possible future prospects and conclusions regarding weed control by allelochemi-cals under integrated crop management strategies are discussed.     

Factors in the Reduction in Grain Number in Winter Wheat by Early-Sowing in Yamaguchi

Abstract

Grain number per spike of wheat is lower in early sowing than in the conventional standard cultivation in Yamaguchi, Prefecture, Japan. Components of the grain number per spike in five cultivars were analyzed with respect to temperature during the spike development period throughout three growing seasons 2001/2002, 2002/2003 and 2003/2004 to find the cause of the problem of early sowing cultivation. The plants sown in early-October and late-November were called the early sown group and the standard group, respectively, in the following. Three of the five cultivars, Hokushin, Akitakko and Nanbukomugi, showed a strong winter habit, which requires very cold temperatures for spike differentiation. The other two cultivars, Iwainodaichi and Airakomugi, had a moderate winter habit. Grain number per spike and grain yield were decreased by early-sowing (compare with the standard group) in almost all cultivars throughout the three growing seasons. The three cultivars which had a strong winter habit had fewer spikelets per spike in the early-sown group than in the standard group. The other two cultivars which had a moderate winter habit had fewer grains per spikelet in the early-sown group. The higher the temperature during the spikelet formation phase, which is from flag leaf initiation to terminal spikelet initiation, the higher the number of spikelets per spike in the standard group. The spikelet number per spike in the early-sown group increased with the increase in productive tillers under fertile conditions. Such conditions also increased the grain number per spike.     

棉花体细胞无性系变异的研究进展

体细胞无性系变异是一种重要的细胞工程育种技术,其应用于棉花育种的前提是建立高效的组织培养诱导再生植株体系.本文简要综述了棉花离体诱导植株再生研究的现状,重点讨论了棉花体细胞无性系变异的表现、利用方法及机理,提出了当前研究存在的问题并对今后的研究进行了展望.     

Advances in Variable Rate Technology Application in Potato in The Netherlands

Precision agriculture is a farming management concept based on observing, measuring and responding to inter- and intra-field variability in crops. In this paper, we focus on responding to intra-field variability in potato crops and analyse variable rate applications (VRAs). We made an overview of potential VRAs in potato crop management in The Netherlands. We identified 13 potential VRAs in potato, ranging from soil tillage to planting to crop care to selective harvest. We ranked them on availability of ‘proof of concept’ and on-farm test results. For five VRAs, we found test results allowing to make a cost-benefit assessment. These five VRAs were as follows: planting, soil herbicide weed control, N side dress, late blight control and haulm killing. They use one of two types of spatial data: soil maps or biomass index maps. Data on costs and savings of the VRAs showed that the investments in VRAs will pay off under practical conditions in The Netherlands. Savings on pesticide use and N-fertilizer use with the VRAs were on average about 25%, which benefits the environment too. We foresee a slow but gradual adoption of VRAs in potato production. More VRAs will become available given ongoing R&D. The perspectives of VRAs in potatoes are discussed.     

我国干热区甘蔗抗旱植蔗主要问题研讨

我国干热蔗区是我国甘蔗糖业的重要生产基地,蔗区光热资源丰富,唯降水分布不均成为植蔗生产的主要限制因子;根据蔗区植蔗特点和甘蔗需水规律,苗期抗旱是干热蔗区抗旱植蔗的关键,保证较多的总苗数和足够的生长量是苗期抗旱植蔗需解决的关键技术难题,制定相应的苗期抗旱植蔗栽培技术措施是解决该难题的重要保障;该观点为我国干热蔗区植蔗生产、甘蔗引育种提供理论和技术支持。     

Diurnal changes in net photosynthetic rate in potato in two environments

Summary Diurnal changes in net photosynthetic rate were measured in a furrow-irrigated potato crop and in a riverbed crop where the water table was always maintained at 20–28 cm from the soil surface. In the irrigated crop, the photosynthetic rate during mid-afternoon was about half the peak rate observed at noon. This reduction was accompanied by a near tripling of stomatal resistance, a 45% reduction in transpiration, and a 5-fold increase in the difference between leaf and air temperatures. No such changes were observed in the riverbed crop where the photosynthetic rate remained nearly constant at about 0.9 mg m⁻² s⁻¹ between 9 a.m. and 4 p.m. Tuber yield in the riverbed crop was about 30% higher than in the irrigated crop.     

2009年中国稻米市场分析及2010年展望

以翔实的资料对2009年中国稻米生产、消费、进出口、供求平衡、库存、价格走势、购销政策和国际稻米供求等情况进行了全面地分析,对影响2010年稻米市场价格走势的各种因素进行了深入研究,并在此基础上对2010年我国稻米市场价格走势进行了预测,结论是我国稻米价格仍呈上行趋势。     

Changes in daily rainfall characteristics in major rice producing provinces in Laos

In order to find the changes in rainfall characteristics and to examine the flood damage to lowland rice, a statistical analysis was carried out on the 40-year daily rainfall record at four rainfall stations (Thangon, Paksane, Seno, and Pakse) in Laos. The rainfall record was divided into two periods of 20 years each. The results of this analysis revealed the trends in changes regarding the frequency and the timing of the heavy daily rainfall events at the four stations. In Paksane in particular, heavy daily rainfall events tended to occur in the latter half of the rainy season.     

玉米抗旱性指标研究进展

干旱作为玉米生长发育最主要的非生物逆境因子,已成为限制玉米产量形成的关键生态因素,也是我国玉米产量产生波动的重要原因,对粮食生产安全构成严重威胁。玉米抗旱性是水分胁迫条件下表现出的一种复杂综合特性,其适应干旱的形态结构是长期进化的结果,其生理指标变化也是一系列适应性改变后的综合表现。当今水资源短缺日益成为突出问题,且对玉米造成干旱的外部因素较多。本文从鉴定方法、形态指标、生理生化等方面阐述玉米抗旱机制与鉴定方法,综述玉米抗旱性最新研究进展。发展抗旱性玉米研究,为创制选育新的耐旱种质提供支撑,最终提升玉米抵御干旱胁迫的能力,这对于保障玉米可持续生产、解决粮食安全具有重要意义。     

Sugar and dry matter changes in potatoes overwintered in soil in Greece

Summary Potatoes were left in the soil from December, when the vines died, until February (cvs Claustar and Sebago) or April (cv. Spunta) in a location of central Greece with light, well drained soils and a mild climate. Tubers were analysed every two months for dry matter and sugar content and usually the dry matter content did not change significantly from December to February or April. The reducing sugars increased from December to February in tubers of all cultivars and significantly decreased in cv. Spunta from February to April.     

兜兰离体快繁技术研究进展

由于生境破坏和人工过度采挖及繁殖的障碍,兜兰已是世界上最濒危的植物物种之一,所有野生种均被列入《濒危野生动植物种国际贸易公约》附录I而被禁止交易。突破其种苗繁殖技术瓶颈有利于兜兰种质资源的保护和可持续利用。本文对兜兰属植物无菌播种、共生萌发和组织培养技术等离体快繁技术的进展进行综述,并提出了目前存在的问题和解决方法,以期为兜兰属植物离体繁殖技术的深入研究和优质种苗的规模化生产提供参考。     

Developments in Potato Storage in Great Britain

Potato storage in Great Britain is focused on delivery of high quality crops for premium markets. For the fresh sector, crops from storage need to have clean skins free from blemish. Control of black dot, silver scurf and skin spot is, therefore, paramount to secure the best returns. Cold storage is used as a primary means of suppressing disease development and sprout growth. Recent work on black dot has also illustrated the importance of the time the crop spends in the ground (measured as crop duration from 50% emergence to harvest) in relation to the level of disease at harvest, with rapid reduction in storage temperature providing best control of the disease once in store. Storage for processing is carried out at higher temperature with the use of CIPC for sprout suppression. Optimisation of the application process has been a primary objective to maintain frying quality and ensure compliance with new legislation on residue levels. The addition of a catalytic converter to a CIPC fogger minimised any detrimental effect of the fogging process on fry colour. The use of CIPC, where the application of fog has been assisted by slow speed ventilation, has proved to be very successful in trials carried out over 3 years in bulk stores. This has resulted in more uniform sprout control across the store and the need for less CIPC per season. Computerised control systems offer close regulation of storage temperature which reduces the likelihood of condensation that can otherwise compromise crop quality. AssiStore?—a new risk-driven decision support system developed at Sutton Bridge for store managers—is now being evaluated in commercial storage. Whilst development of enhanced management and control remains a key element of storage improvement strategies, it must be remembered that the important aspect of any control system is to ensure the interface with the operator is sound to ensure that any system is meaningful and easy to use. PCR diagnostics also offer great potential for identifying likely storage risks at harvest more accurately; a new test for skin spot has just been successfully developed. As storage becomes more sophisticated, costs inevitably increase. These have been recouped in recent years through improved quality delivered from store. But now there is a need to apply new, more sustainable approaches in order to lower inputs and reduce losses. Developments include the use of inverter drives to match ventilation (and hence energy needs) to demand, and humidification which offers scope for lowering weight loss and providing adiabatic cooling. Reduced reliance on chemicals is also needed and, whilst the adoption of ethylene for fresh market storage has been a significant step forward in recent years, it remains likely that the plant breeders will offer the most sustainable and cost-efficient route to effective storage in the longer term.     

Chrysin Reduced Acrylamide-Induced Neurotoxicity in Both in vitro and in vivo Assessments

Background: Acrylamide (ACR) is a well-known industrial toxic chemical that produces neurotoxicity, which is characterized by progressive central and peripheral neuronal degeneration. Chrysin is a natural, biologically active flavonoid compound, which is commonly found in many plants. The antioxidant and neuroprotective properties of chrysin have been demonstrated. Methods: In this study, the possible effect of chrysin on ACR-induced toxicity was evaluated in both in vitro and in vivo experiments. PC12 cells were used as a suitable in vitro model. Cells were exposed to chrysin (0.5-5 µM) for 12 and 24 h, and then ACR in IC₅₀ concentration was added to the cells. Finally, cell viability was determined using (4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium assay. For in vivo assay, Wistar rats were treated with ACR (50 mg/kg i.p. for 11 days) alone or in combination with chrysin (12.5, 25, and 50 mg/kg). At the end of treatment, behavioral index was evaluated. Results: ACR decreased cell viability and pre-treatment with chrysin (0.5-5 µM) significantly decreased ACR-induced cytotoxicity in the time- and dose-dependent manner. In Wistar rats, exposure to ACR significantly induced severe gait abnormalities, but treatment with chrysin (50 mg/kg) reduced ACR-induced neurotoxicity in animals. Conclusion: In the current study, chrysin exhibited neuroprotective effect on PC12 cells as an in vitro model and also on Wistar rats. Iran. Key Words: Acrylamide, Chrysin, Neurotoxicity, Antioxidant     

中国马铃薯单倍体诱导进展

马铃薯产量、品质、加工等方面都较其他作物有更大的提升空间,但由于四倍体马铃薯存在遗传基础狭窄且复杂、难以创新等诸多问题阻碍了相关研究的深入开展。利用马铃薯单倍体或双单倍体植株有望解决上述诸多难题。马铃薯单倍体具有加速育种过程、提高选择效率等优点。马铃薯单倍体的获得包括花药培养、花粉培养、孤雌生殖、子房培养。其中,花药培养因更易取材,并且得到胚性细胞团、愈伤组织或胚状体的几率更大等优点而研究最为广泛。获得单倍体植株的成功率与试验材料的基因型、培养条件、培养基添加物等诸多因素相关。根据不同的诱导方法简要阐述了中国马铃薯单倍体研究的历史及进展。     

Changes in chlorpropham residues in stored potatoes

Chlorpropham (CIPC)³ concentrations were measured in peel samples of tubers taken from large commercial potato storages and from test bins after aerosol application. Tuber samples were taken at different levels within the pile and at numerous sites near the surface. The minimum concentration of CIPC in the peel layer for complete inhibition of sprouting was estimated to be 20 ppm. Immediately after commercial application of CIPC, 99% of the sample sites had concentrations high enough to completely inhibit sprouting, and residues in the peel were generally highest in samples obtained from the surface and from the bottom of the pile. CIPC concentrations decreased during the storage season in nearly all sites tested. Storages differed in the rate at which CIPC was lost. Mean peel residues fell below the level necessary for sprout inhibition in some storages but not in others. The rate of CIPC loss increased at the same time that air movement to maintain the desired temperature increased. With the 20 ppm threshold level as a guide, it is possible to monitor commercial storages for sprout-inhibition status. Retreatment before peel residues drop below 20 ppm can extend sprout inhibition in storage.     

Temporal variation in the recovery from impairment in adriamycin-induced wound healing in rats

Background  

An adriamycin-induced impairment of wound healing has been demonstrated experimentally in rats. The purpose of this study is to investigate a possible temporal variation in recovery from the impairment of wound healing caused by adriamycin administration.     

我国高粱育种研究进展

对我国高粱育种的主要途径和研究方向进行了概述,针对目前高粱产量徘徊现象,提出了高粱超高产育种设想,并对其技术路线进行了探讨。     

广东花生抗青枯病育种研究进展

广东70％～80％的花生种植在轮作周期较短的瘦瘠旱坡地上,青枯病危害较重,严重威胁花生生产。在调查品种与发病关系中,发现花生抗青枯病力在类型间和品种间有明显差异,因此,应以品种抗病性鉴定和选育作为研究的主攻方向。利用国内外花生品种资源鉴定筛选出抗原材料并通过各种育种途径,选育出高产抗青枯病的花生品种投入生产,减轻青枯病危害,提高花生单产和总产。