钙信使在植物适应非生物胁迫中的作用

Ca2+作为植物细胞中的第二信使,参与植物对多种非生物逆境信号的转导。在非生物逆境条件下,植物细胞质内的钙离子在时间、空间及浓度上会产生特异性变化,钙信号再通过其下游的钙结合蛋白进行感受和转导,进而在细胞内引起一系列的生物化学反应,以适应或抵制各种逆境胁迫。通过从植物在非生物逆境条件下钙信号的产生、传递、特点和作用方式,以及钙在各种非生物逆境响应中的作用等方面对钙信号转导进行综述。     

施加外源钙素对白魔芋生长的影响

钙素是植物生长发育不可缺少的元素之一。为探索外源钙灌施对白魔芋生长形态及叶绿素、丙二醛等生理指标的影响，以黔东南凯里学院种植的白魔芋作为试验材料，在白魔芋生长期，于根部灌施不同浓度的外源钙(19kg/hm²、38kg/hm²、76kg/hm²)，通过测定不同浓度下白魔芋株高、茎粗、叶面积等形态指标和叶绿素、MDA生理指标的含量变化，分析施加外源钙素对白魔芋生长的影响。结果表明，施加外源钙对白魔芋株高、茎粗、叶面积、叶绿素含量均有促进作用，而对丙二醛含量有一定抑制作用，且外源钙最适宜浓度为38kg/hm²。     

外源钙对干旱胁迫下复羽叶栾树幼苗水分及光合特性的影响

以1a生复羽叶栾树幼苗为试材,采用称重控水法模拟干旱,研究了外源钙处理对不同干旱胁迫条件下植物幼苗相对含水量、光合特性的影响.结果表明:经外源钙处理,有利于从整体上缓解干旱环境对幼苗的影响,保证植物在逆境中正常生长.对于相对含水量而言,胁迫越严重,下降的幅度越大;经外源钙处理,同一胁迫水平下幼苗相对含水量下降的幅度、速度均减小并且与无钙组同水平处理组均表现出显著性的差异,但并不能使相对含水量恢复到对照水平.植物一般采取低光合、低蒸腾、高水分利用效率的策略来适应干旱环境;通过外源钙处理,光合速率降低的速度及幅度减小,蒸腾作用进一步减小,同时减小了气孔导度的降低,并且提高了干旱条件下的水分利用效率.     

钙与果实采后生理生化变化

钙是植物细胞内功能调节的第二信使。钙处理在延缓果蔬采后衰老方面,具有保持果实硬度、降低果实呼吸,减少乙稀释放和防止生理病害等作用。将浸钙处理与热处理相结合用于苹果贮藏,其保鲜效果明显优于任何一种单一处理。因此,钙对果蔬采后所产生的生理效应,正受到更加广泛的关注。本文就近年来有关钙处理对果实采后生理生化变化的影响作一综述。1钙处理对果实钙水平和果实硬度的影响采前或采后处理均可增加果实的钙水平,而果实硬度与果实中的钙水平呈正相关。较高的钙水平不仅能增加果实硬度,而且能延缓果实的软化。钙处理还影响钙在…     

钙的生理作用及钙肥的施用方法

<正>近年来,由于土壤酸化、追求高产、化肥施用不合理,以及在酸性土壤上种植需钙较多的作物,碱性土中钠含量过高,中性土大量施用氮、磷、钾、镁肥及微量元素肥料后又未补钙,造成土壤钙的供应不足,导致化肥利用率低,土壤结构变差,植物抗逆性降低,生长受阻,产量品质下降。很多种植者未能认识到钙在土壤和植物生长中的重要性,将缺钙症误诊为有机肥施用不足、化肥施用量过多造成的。在此,笔者谈     

植物根系研究进展

根系是植物体的地下部分,是植物长期适应陆地条件而形成的一个重要器官,具有锚定植物、吸收输导土壤中的水分养分、合成和储藏营养物质等生理功能。根的发育过程比较复杂,而且因不同种类的植物和环境条件而异,形成了不同的根系类型、形态结构、生理功能及生长特性。现对植物根系的生理机制、根系活力、根系环境胁迫及根系的形态构型等进行了概述。     

果树的钙素营养

钙素是植物生长必需的矿质营养元素之一，许多果树的生理病害与钙素营养失调有关。钙素对于防止果实腐烂、保持果实硬度和减少乙稀释放量都是有效的阳离子。钙在植物中“既起着结构成分也起着某些酶的辅助因素的功能”。因此，钙不仅以膜结构和果胶酸钙的形式沉积于细胞壁，而且作为细胞内功能调节的第二信使，与钙调蛋白结合后调节了多种酶的活性和细胞功能。     

VA菌根真菌在马铃薯上的应用效果

菌根（Mycqrrhizae）是土壤中的一类真菌与宿主植物根系所建立的互惠共生体。菌根真菌能与大多数植物共生，促进植物对氮、磷、钾、锌、铁、铜、硫、钙等矿质元素的吸收，提高植物抗旱性，促进植物生长发育，提高植物对某些病害的防御能力。因此利用微生物自身的生长、繁殖、侵染而改善植物生长的根际环境，达到使植物增产、增效的目的，不失为一个好的发展方向。     

黑龙江大庆地区园林绿化中盐碱土壤改良方法探析

土壤作为植物生长的必要物质,对栽植的植物成活、生长影响更是不容忽视。土壤是植物生长环境中的必要物质条件,园林施工工程中,通过土壤改良为园林植物创造良好的生长环境,是提高施工质量的重要环节,也是提高园林植物成活率的关键工序。土壤严重碱化是盐碱地城市绿化最大的技术难点。通过对盐碱土壤的改良降低其对植物的危害,选择适合本地区生长的耐盐碱植物进行种植,可以有效解决盐碱地城市的园林绿化问题。     

植物逆境生物学中的蛋白质组学技术运用探析

逆境胁迫在植物生长发育中起重要作用,对植物生长质量产生直接影响。现阶段揭示植物的应答胁迫分子的机理已经成为人们探索研究的重要课题。而植物蛋白质组学研究能揭示不同胁迫状况下,植物蛋白质的具体表达情况,有助于帮助人们深入了解环境胁迫下的植物基因表达调控机制及植物响应胁迫机理,介绍了蛋白质组学研究技术,概述了植物逆境胁迫适应机制在研究中的具体应用,展望了低蛋白质组学在植物逆境生物学领域的发展状况。     

Effects of light intensity and quality on the obligate shade plant Aglaonema commutatum. I. Leaf size and leaf shape

The effect of different light intensities and light qualities were studied on Aglaonema commutatum plants grown in controlled environments. Three light intensities—2.7, 5.4 and 20.0 junolm-2s-1 provided by two light sources (fluorescent and blended-light lamps) were tested on two plant materials of different size. When plants completed their adaptation to low light intensities (2.7 and 5.4 umol m“2s_1) readaptation to high irradiances (20.0 (xmol m-2s_1) was studied. Ten to twelve months were required for a leaf initiated in each light treatment to become fully expanded. The adaptation of this species to low light was far slower than other sun- or shade-plants. Plants grown at 2.7 |xmol m-2s~‘ expanded smaller and thinner leaves, with lower length: width ratio. These responses were affected by the size of the primordia at the beginning of the light treatments. Light quality affected these too but the responses were weak and lacked a defined pattern. The readaptation to high light intensity of plants adapted to 2.7 or 5.4 (xmol m_2s_1 required 6-8 months, after that leaves showed the same sizes and shapes as controls in high irradiance.     

Molecular and cellular aspects of calcium action in plants

Calcium is known to be a second messenger in many developmental processes in animal systems, but it has only recently become evident that Ca is an important intracellular messenger in plants as well. The level of free Ca concentration in the cytoplasm is extremely low, and it is influenced by extracellular signals such as light, gravity, and hormones. Investigations from our laboratory indicated that Ca and its binding protein, calmodulin, play an important role in stimulus-response coupling by regulating enzyme activities, especially through protein phosphorylation. In vivo and in vitro protein phosphorylation studies have revealed Ca-dependent changes in various plant tissues. We have also been able to influence various physiological processes such as cell elongation, abscission, senescence, and tuberization by altering extracellular and intracellular Ca levels. Other examples of Ca-mediated processes in plants are as follows: a) cell division, b) geotropism, c) protoplasmic streaming, d) stomatal control, e) chloroplast movement, f) secretion, g) hormone-dependent changes, h) enzyme activation, and i) protein phosphorylation.     

植物逆境胁迫中活性氧和钙信号的关系

钙信号参与植物对逆境的应答反应已被广泛证实,但近年来许多研究发现,活性氧信号也参与了植物对逆境胁迫的应答反应。现介绍植物中活性氧和钙信号的产生机制、活性氧和钙信号对植物逆境胁迫的应答机制,探讨了植物逆境胁迫中活性氧与钙信号之间的相互关系。     

Elimination of toxicity from polyurethane foam plugs used for plant culture

Polyurethane foam plugs commonly are used as collars or supports to grow plants in solution culture. Despite their utility, these foam plugs can be quite toxic to plants, particularly to small seedlings. We have observed tissue injury in tests using plugs to support lettuce, red beet, and potato plants in solution culture. Typically, the injury is initiated on the hypocotyl or stem tissue in direct contact with the foam, and appears within 30 hr as a brownish discoloration on the tissue surface. This discoloration can be followed by complete collapse of affected tissue and eventual death of the seedling. When injury does not progress beyond surface browning, the seedling survives but growth is slowed. In this paper, we report on different treatments that can be used to remove the toxicity of these plugs so they can be used in plant research.     

Effect of propagation material on some quality attributes of strawberry fruit (Fragaria x ananassa, var. Selva)

In the Mediterranean region, cold-stored plants (summer planting system) are used as the main strawberry planting material (plant establishing period July–August). However, recently fresh plants (winter planting system) have also started being used for strawberry production (plant establishing period October–November). As the plantations originated from cold-stored or fresh plants differ in plant growth and yield, some differences in fruit quality have also been expected; therefore, the objective of the current study was to compare fruit quality of plants originated from different propagation material. Cold-stored plants were well developed before the beginning of the spring harvest, while fresh plants continued growth concomitantly with fruiting. The harvesting period of cold-stored plants lasted 4–6 weeks (second week of April–second half of May). Fresh plants produced fewer and larger fruits than cold-stored plants, but for a longer harvest period, which lasted throughout all summer. Differences in soluble solids and dry matter content between the fruits from cold-stored and fresh plants were observed in the first three sampling dates in both years of the experiment. In some sampling dates, significant differences in anthocyanin, titratable acidity and ascorbic acid content, were observed between fruits of plants originated from different propagation material.     

Effect of three Greek arbuscular mycorrhizal fungi in improving the growth,nutrient concentration,and production of essential oils of oregano and mint plants

Arbuscular mycorrhizal fungi have been widely used in agriculture to improve the cultivation of many crops. One of the aims of this study was the isolation and molecular identification of arbuscular mycorrhizal fungi isolated from mountain areas of Northern Greece (Ritini Pieria, Elatochori Pieria, Ambelakia Ossa). Only three isolates were obtained; two of Glomus etunicatum and one of G. lamellosum. The second objective of this study was to investigate the effect of these arbuscular mycorrhizal fungi on the concentration of macro- and micronutrients in tissues, the quantity and quality of essential oils and the growth of oregano and mint plants (two widely used aromatic plants in Greece). It was found that mycorrhizal oregano and mint plants had a higher content of essential oils and nutrient elements, and grew better than non-mycorrhizal plants. In addition, the composition of the essential oil in mycorrhizal plants differed from the oil of non-mycorrhizal plants. These results suggest that the use of mycorrhizal fungi may allow plant growth in low fertility soils, reduce fertilizer inputs and increase aromatic plant production of essential oils, They also indicate that it may be possible to use mycorrhizae to affect the quality of the essential oil produced.     

Control of water and nutrients using a porous tube: a method for growing plants in space

A plant nutrient delivery system that uses a microporous, hydrophilic tube was developed with potential application for crop production in the microgravity of space. The tube contains a nutrient solution and delivers it to the roots. Pumps attached to the tubing create a very small suction that holds the solution within the tube. This system was used to grow wheat (Triticum aestivum cv. Yecora Rojo) for 107 days in a controlled environment at suctions of 0.40, 1.48, or 2.58 kPa. The water absorbed through the pores of the tube by baby diaper sections decreased as suction increased. Correspondingly, final plant biomass, seed number, and spikelet number also tended to decrease as suction increased. The reduced yield at higher suction suggests that the plants experienced water stress, although all suctions were below those typical of soils at field capacity.     

Ethylene production as an indicator of stress conditions in hydroponically-grown strawberries

As a soilless system, hydroponics eliminates competing weeds and soil-born pests while conserving water and providing conditions that can be quickly altered to suit specific crops. However, stress-induced physiological conditions may arise within the system from factors such as mechanical injury, pests, or inconsistent nutrient flow rates that result in some plants receiving too much or too little water. Most abiotic stress conditions result in increased production of the plant hormone ethylene. High levels of ethylene inhibit growth, cause premature ripening, and induce the onset of senescence, potentially reducing the productivity of hydroponically-grown crops. In this study, we demonstrate that assessing ethylene levels from leaves of hydroponically-grown strawberry plants can be used as an early indicator of stress conditions. Our results demonstrate that there is no significant correlation between ethylene production and temperatures ranging from 15 to 37 °C or with light intensities ranging from 63 to 1500 μmol m⁻² s⁻¹. However, an increase in ethylene production tended to be positively correlated with sampling time; levels were higher during midday compared to early morning or later afternoon. The daily ethylene fluctuations under greenhouse conditions due to sampling time, light intensity, or temperature changes were not significantly high enough to indicate stress conditions. Overall, three system analyses showed altered ethylene production in plants farthest from the pump supplying the nutrient solution. This effect was interpreted to be caused by excess accumulation of nutrient solution around the plant roots, causing increased ethylene production in the leaves. Our results indicate that different watering patterns, manifested as pump pressure or drainage control, was the more difficult component to control in the design of these hydroponic systems. For example, in one system, an increase in ethylene production was measured for the position farthest from the pump, and resulted in those plants having a lower number of flowers and significantly reduced overall plant radii relative to the system average. In a separate experiment, plants from trays that had been flooded for 24 h showed a significant decrease in the plant radii and number of leaves and flowers 1 month after the flooding treatment. We conclude that system-wide ethylene measurements can be used to identify stressed plants within hydroponic systems. This type of analysis would be especially useful as an indicator of general stress conditions no matter the cause, identifying locations that may result in lower plant productivity.     

A regulation-oriented approach for allergenicity categorization of plants

Plant species have different degrees of allergenicity. Existing systems categorizing plants according their allergenicity were reviewed to find a method that could serve as the basis for the regulation of green areas. The categorization of plants by their allergenicity serves different purposes: informing allergic patients, warning consumers in horticultural stands, or evaluating urban green areas. The regulation of allergenic plants in trade and their use in urban greening is a new, emerging application of allergenic categorization. Our review showed that the existing systems cannot be used for this purpose, because they cannot fulfill the main requirements of regulation: the methods were often not described, and this affected reproducibility and there was a lack of evidence on allergenicity. To overcome these issues, a new, evidence-based categorization (CARE-S) was developed using genetically determined factors of plants: immunogenicity, morphology, and pollen production. 529 plant taxa were categorized, mostly those common in urban areas in the Pannonian Biogeographical Region. The new system can be applied in other biogeographic areas and on new plant varieties by an online calculator tool. An adaptation strategy of CARE-S in regulations is also proposed. Additional benefits of CARE-S: 1: promoting the development of low-allergenic cultivars, 2: identifying overlooked allergens, recommending their use in clinical tests, 3: calling attention to plant taxa which need more research in allergology or botany; 4: providing a legal tool to prevent the introduction and dispersal of (new) allergenic plants. As a further step the authors suggest developing another tool, epidemiological allergenicity, derivated from CARE-S, aiming to characterize the geographically-determined effects of plants on human populations.     

NaCl胁迫下石榴和桃植株Na^＋,K^＋含量与耐盐性的研究

石榴和桃是两种耐盐性不同的果树。前者在含盐（ＮａＣｌ，以下同）０．３％土壤上植株Ｎａ＋含量有少量增加，含盐量达０．４％时才大量增加；后者在含盐０．２％的土壤上Ｎａ＋含量增加不多，含盐０．３％土壤上急剧增加。盐处理明显增加植株Ｋ＋含量，Ｋ＋／Ｎａ＋增加。植株Ｋ＋／Ｎａ＋值，石榴平均约为桃的１．５倍，死亡植株Ｋ＋／Ｎａ＋值小于１。ＲＰＸＫＮａ、ＲＳＫＮａ及ＳＸＰＫＭＡ值表明，Ｎａ＋、Ｋ＋经过石榴根系时，Ｎａ＋被韧皮部细胞积累，Ｋ＋优先进入木质部，Ｎａ＋、Ｋ＋从根系向枝条运输时及从枝条木质部向韧皮部转运时，Ｎａ＋被木质部再吸收，Ｋ＋优先向地上部及枝条韧皮部积累。桃对Ｎａ＋、Ｋ＋的选择吸收运输能力较石榴弱。