The Effect of Moisture Content on the Low Temperature Responses of Araucaria hunsteinii Seed and Embryos

The effect of moisture content on the low temperature responsesof 'recalcitrant' Araucaria hunsteinii seed and excised embryoswas investigated in relation to germination and storage. At6°C seed longevity was decreased as mean moisture contentwas reduced from 45 to 30% (fresh weight basis); the time predictedfor the loss of one probit of germination,     

Effects of Desiccation and Cryopreservation on the In Vitro Viability of Embryos of the Recalcitrant Seed Species Araucaria hunsteinii K. Schum

Embryos excised from fresh seed had a moisture content of about37% (fr. wt.), 7% above that of the whole seed: mainly as aresult of the dryness of the seed coat. When cultured for 14d at 26°C embryo growth ranged from unorganized to fullyorganized. Embryos which had been directly surface-sterilizedexhibited lower fully organized growth than aseptically excisedembryos. During desiccation of the whole seed at 15°C and 15% r.h.moisture loss from the embryo was slow until the embryo reacheda mean critical moisture content for fully organized growthin vitro of about 30%. After this point the rate of moistureloss increased, quickly diminishing the moisture content differentialbetween the embryo and the whole seed. No such shoulder in theembryo desiccation curve was observed when using a low viability(7%) seed batch. When dried below 30% moisture content, suchaseptically excised embryos increasingly exhibited unorganizedgrowth in vitro, with only root meristem survival (46%) at 13%moisture content. In contrast, a much higher level of root meristem survival (84%of control) was observed when aseptically excised embryos wererapidly desiccated to 13% moisture content, using a flow ofsterile air. However, the benefits of rapid drying were lostif the embryos were directly surface-sterilized prior to desiccation.Furthermore, 80% of aseptically excised embryos which survivedrapid desiccation to 20% moisture content exhibited root meristemsurvival following subsequent cryopreservation. These findingshave implications for the in vitro conservation of recalcitrantseed tissue. Key words: Araucaria hunsteinii K. Schum., recalcitrant seed embryo, desiccation, cryopreservation     

The Effect of Desiccation on the Longevity of Seeds of Araucaria hunsteinii and A. cunninghamii

Seeds of Araucaria hunsteinii K. Schum. dried quicker at 29°Cthan at 19°C and quicker with the seed-coat removed thanwhen intact; seeds enclosed in polyethylene bags increased inmoisture content. At 15°C, seeds in a flow of air driedquicker than seeds in a box with silica gel, which in turn driedquicker than seeds in a box with no desiccant. No loss of germinationability occurred on drying fresh seed from 53 to about 32 percent moisture content (fresh weight basis); during further desiccationthe percentage germination was related to percentage moisturecontent in the form of a sigmoid curve, culminating in a completefailure to germinate at approximately 14 per cent moisture content.A consistent relationship was observed for all treatments andthe mean critical moisture content for seed death (failure togerminate) was near 23 per cent. Excised embryos grew on 1 percent agar but died if previously subjected to 14 h of desiccationat 15°C. In contrast, no relationship was found between germination andmoisture content of A. cunninghamii D. Don on desiccation from21 to 7 per cent moisture content. Possible causes for the observeddifference in response to desiccation are discussed and methodsfor seed storage are considered. Araucaria hunsteinii, Klinkii pine, Araucaria cunninghamii, Hoop pine, desiccation, seed longevity, storage of seeds     

The Viability of Rice Seed in relation to Temperature, Moisture Content, and Gaseous Environment

The seed viability of a tropical variety of rice has been investigatedin hermetic storage under a range of conditions of temperatureand moisture content. The results confirm a previous suggestion,which was made on the basis of data from temperate cereals,that the relationship between these factors and viability canbe described in simple mathematical terms. In addition, a comparisonhas been made of the effects on viability of hermetic storagein air, oxygen, nitrogen, and carbon dioxide.     

种子超干贮藏技术应用面临的问题和研究方向

种子超干贮藏技术对种质资源保存具有很大的应用前景,但鉴于目前的研究进展,其应用还存在诸多技术上的问题。本文对种子超干贮藏技术在种子库中应用所面临的挑战以及需要开展的研究内容进行了如下几个方面的讨论：种子贮藏安全含水量下限的多样性决定了超干技术应用的复杂性;超干贮藏含水量安全下限的确定尚未有可靠的方法;超干贮藏的种子吸胀前需要恰当的预处理以避免吸胀损伤;超干处理前外源抗氧剂预处理可能改善超干贮藏效果;无氧条件可能对超干贮藏具有增效作用;糖类物质以及两性物质对种子在超干处理及超干贮藏过程中的保护作用。     

含水量对种子贮藏寿命的影响

建立以收集种子为主体的基因库乃是当今保护植物种质资源最为普遍且可靠易行的方式,在世界库存约 61 0 0 0 0 0份种质资源中,近 90 %是以种子形式保存于约 1 30 0个基因库中。低温贮藏仍是目前基因库中种子种质保存的主要方法。种子含水量和贮藏温度是影响种子在贮藏期间生活力和活力保持的关键因素。传统的经验认为控制温度比控制水分来得安全有效,因而趋向于向低温或超低温的贮藏方向发展。国际植物遗传资源研究所（ＩＰＧＲＩ）曾推荐 5%～ 6%的含水量和 - 1 8～- 2 0℃低温作为各国长期保存种子的理想条件。目前,世界各国都把更多的…     

Storage reserves and cellular water in mature seeds of Araucaria angustifolia

Seed tissues of Araucaria angustifolia (Bertol.) Kuntze were investigated using histochemistry, transmission electron microscopy (TEM) and energy dispersive X-ray (EDX) analysis. Moisture content and water status in tissues were also evaluated. In the embryo, TEM studies revealed the presence of one to several central vacuoles and a peripheral layer of cytoplasm in cells from different tissues of the cotyledons and axis. In the cytoplasm, lipid bodies, starch grains, mitochondria and a nucleus are evident. In most tissues, vacuoles contain proteins, indicating that the storage proteins are highly hydrated. In cells of the root cap, proteins are stored in discrete protein bodies. Both protein storage vacuoles and discrete protein bodies have inclusions of crystal globoids. EDX analysis of globoids revealed the presence of P, K and Mg as the main constituents and traces of S, Ca and Fe. In the root and shoot meristems, deposits of phytoferritin are present in the stroma of proplastids. The gametophyte consists of cells characterized by relatively thin cell walls and one to several nuclei per cell. Protein and lipid bodies are present, although starch is the most conspicuous reserve. Immediately after shedding, moisture content is approximately 145% (dry weight) for the embryo and 95% (dry weight) for the gametophyte. Calorimetric studies reveal that axes and cotyledons have a very high content of freezable water, corresponding to types 5 and 4, i.e. dilute and concentrated (or capillary) solution, respectively. The results are discussed in relation to the behaviour of the species, which has been categorized as recalcitrant.  © 2002 The Linnean Society of London . Botanical Journal of the Linnean Society , 2002, 140 , 273−281.     

利用本地资源设计研究性学习活动一例——明矾对种子萌发影响的实验探究

通过开发本土环境资源,开展研究性学习,可以充分发展学生的探究能力。同时也为课堂教学积累丰富的课程资源,从而实现研究性学习校本化,课堂教学研究化。本文通过实验探讨了世界矾都的污染状况,以不同浓度的明矾溶液对植物种子萌发的影响来说明问题,实验表明浓度越高种子萌发率就越低,茎高也越低,根的末端干枯,坏死,表明了明矾对种子萌发有很强的毒害作用。     

Glassy State and Seed Storage Stability: The WLF Kinetics of Seed Viability Loss at T>Tgand the Plasticization Effect of Water on Storage Stability

The relationship between the glassy state in seeds and storage stability was examined, using the glass transition curve and a seed viability database from previous experiments. Storage data for seeds at various water contents were studied by Williams–Landel–Ferry (WLF) kinetics, whereas the glass transition curves of seeds with different storage stability were analysed by the Gordon–Taylor equation in terms of the plasticization effect of water on seed storage stability. It was found that the critical temperatures (T_c) for long-term storage of three orthodox seeds were near or below their glass transition temperatures (T_g), indicating the requirement for the presence of the glassy state for long-term seed storage. The rate of seed viability loss was a function of T-T_gat T>T_g, which fitted the WLF equation well, suggesting that storage stability was associated with the glass transition, and that the effect of water content on seed storage was correlated with the plasticization effect of water on intracellular glasses. A preliminary examination suggested a possible link between the glass transition curve and seed storage stability. According to the determined WLF constants, intracellular glasses in seeds fell into the second class of amorphous systems as defined by Slade and Levine (Critical Reviews in Food Science and Nutrition30: 115–360, 1991). These results support the interpretation that the glassy state plays an important role in storage stability and should be a major consideration in optimizing storage conditions.     

贮藏温度和种子含水量对洋葱种子发芽率的影响

贮藏温度低于15℃时,温度对洋葱种子发芽率影响变小,种子含水量低于8.8%时,其衰老过程变慢,高含水量种子在高温下贮存,衰老过程加快,含水量为100%和13%的种子在25℃下贮存分别不到5个月和2个月就失去商品性。     

Forming of the Gaseous Environment by Insects in the Intergranular Air

Entomological Review - It is experimentally shown that intergranular air in the wheat stock infested by insect pests has a substantially higher concentration of carbon dioxide with significantly...     

洋葱种子含水量与贮藏温度对其寿命的影响

不同含水量（MC7.1％～1.2％）的洋葱种子贮藏在35℃、室温、15℃和5℃条件下1～3年,适度超干处理能延长种子的贮藏寿命;种子的贮藏寿命与种子含水量和贮藏温度密切相关。种子贮藏的最适含水量随温度的改变而发生相应的变化,35℃时MC为3.4％;室温时为3.4％～4.5％;15℃时为4.5%～5.1％。MC≤2.2％不利于延长种子寿命。在室温自然条件下贮藏1～3年,适度超干种子（MC3.4％）内MDA和H2O2含量、O－*2产生速率和LOX活性明显地低于未超干种子（MC7.1％）和高度超干种子（MC1.2％）,而抗氧化酶AsA-POD、CAT和SOD的活性显著地高于未超干种子（MC7.1％）和高度超干种子（MC1.2％）。据此认为对脂质过氧化的抑制作用是适度超干种子耐贮藏的生理原因之一。     

超干贮藏对芥兰种子生活力和活力的影响

1年的监测结果显示：芥兰种子开放贮藏时的生活力和活力下降最快,超干种子(含水量为4．91％、3．25％和2．84％)具有良好的耐藏性,其种子发芽率和简化活力指数增大,抗老化能力、超氧物歧化酶和过氧化氢酶的活性增强,膜进性降低,以2．84％含水量的芥兰种子贮藏效果为最好。     

The Effect of Film Permeability on the Storage Life and Microbiology of Vacuum-packed meat

Joints of beef were stored in packaging films with oxygen permeabilities ranging from 0–920 ml/m²24 h/atm at 25 °C and 100% r.h. The storage life of the 'vacuum-packaged' meat, as assessed by discolouration and the development of putrefactive odours, was inversely related to film permeability; the best results were obtained with meat which received 'zero oxygen' treatment. The growth rates and final counts of Pseudomonas spp. increased with increasing film permeability; the storage life of the meat corresponded with the time taken for the counts of the organism to reach ca. 10⁶/cm² for putrefactive odours to be produced. Although their growth rate was unaffected, the final counts of Brochothrix thermosphacta also increased with increasing film permeability. These results are discussed in terms of the influence of film permeability on the inhibitory effects of Lactobacillus spp., whose numbers were unaffected by the permeability of the film used, and the substrates in the meat available to the bacteria.     

Some Properties of Proteolytic Enzymes and Storage Proteins in Recalcitrant and Orthodox Seeds of Araucaria

Araucaria bidwillii Hook. and Araucaria cunninghamii Don D. are two species of conifers whose seeds belong to different physiological categories: A. bidwillii seeds are recalcitrant, while A. cunninghamii seeds are orthodox. The extraction of enzymes and storage proteins was carried out from A. bidwillii and A. cunninghamii megagametophytes. The endopeptidase activities of both species were assayed with azocasein and with haemoglobin; the exopeptidase activities were detected by various N-carbobenzyloxy-dipeptides and L-leucine p-nitroanilide. The use of appropriate proteinase inhibitors, i.e. pepstatin A, ethylenediaminetetraacetic acid and trans-epoxysuccinyl-L-leucylamido-(4-guanidino)butane, showed the presence of aspartic and metallo proteinases and the absence of the cysteine ones both in A. bidwillii and in A. cunninghamii ungerminated seeds. Since the results do not show differences between the types of enzymes in the ungerminated araucarian seeds and those present in some ungerminated angiosperm seeds (barley, wheat, maize, rice, buckwheat), we conclude that their physiological role is similar. The electrophoretical analyses of soluble and insoluble storage proteins of A. cunninghamii showed patterns similar to those found in other gymnosperms, while the storage protein patterns of A. bidwillii seeds were rather atypical.     

The Influence of Polyacetylenes on the Susceptibility of Carrots to Storage Diseases

The amounts of the polyacetylenes falcarindiol (heptadeca-1, 9(Z)-dien-4,6-diyn- 3,8-diol) and falcarinol (heptadeca-1,9(Z)-dien-4,6-diyn-3-ol) were determined in the roots of a number of commercial carrot cultivars in order to study their influence on resistance to storage rots caused by three different fungi. The content of the diol was much higher in periderm/pericyclic parenchyma than in phloem parenchyma and the outer tissues were less susceptible to Mycocentrospora acerina than the inner tissues. A strong and significant negative relationship was found between falcarindiol contents in the periderm/pericyclic parenchyma and susceptibility to Mycocentrospora acerina for 14 of the 16 cultivars tested. The relationship was less noticable for Sclerotinia sclerotiorum and not significant for Rhizoctonia carotae.     

The Effect of Storage in Various Gaseous Atmospheres on the Microflora of Lamb Chops Held at—1°C

The effect of different gaseous atmospheres on the development of the bacterial flora on lamb chops stored at –1°C was examined. The atmospheres were air, nitrogen, hydrogen, and mixtures of air + carbon dioxide, oxygen + nitrogen, oxygen + carbon dioxide, nitrogen + carbon dioxide and hydrogen + carbon dioxide (gas ratio = 80:20, v/v). Storage life of chops ranged from two weeks in air to eight weeks in oxygen-free atmospheres. At the end of storage life Microbacterium thermosphactum was present as a major constituent of the bacterial flora in all atmospheres. In oxygen + carbon dioxide it was the predominant organism. In all other oxygen containing atmospheres, Pseudomonas spp. made up a large proportion of the flora. Strains of Enterobacteriaceae occurred in low-oxygen and oxygen-free atmospheres, and Lactobacillus spp. occurred in oxygen-free atmospheres.     

伯乐树种子不同条件贮藏下前后生理比较

对3个不同地区（浙江省遂昌县、福建省浦城县和浙江江山市）的伯乐树种子形态指标进行了测定。并分别设置3种贮藏方式（A为室内湿沙环境下贮藏;B为低温（4℃）湿沙下贮藏;C为低温（4℃）封口袋中贮藏）,对贮藏前后种子的发芽率、发芽势、含水量等生理指标进行了比较研究。结果表明,浦城县地区较另外二个地区的种子狭长而扁平,且质量较小。经130d的贮藏后,3个地区的种子内淀粉含量显著下降（P〈0．05）,含水量、蛋白酶活性、淀粉酶活性、蛋白含量和可溶性糖含量则均显著升高（P〈0．05）,从而使休眠得以解除。贮藏后的发芽率和发芽势显著提高（P〈0．05）,以湿沙低温下的发芽率和发芽势为最高。     

水稻种子贮藏谷蛋白的微细异质性

利用灵敏的等聚焦与SDS－PAGE合的双向电泳分析方法,从水稻（Oryza sativa L.)种子贮藏谷蛋白中至少可以分离为13条酸性和19条碱性多 肽,依据谷蛋白多肽的表现量推测,水稻谷蛋白主要由约6个主效基因控制,肽图谱与N－端氨基酸序列分析可清晰将谷蛋白酸性多肽分为两组,此两组恰好与谷蛋白GluA和GluB两个cDNA克隆组相吻合。