Misconceptions About the Relation Between Plant Growth and Respiration

Abstract: The relation between plant growth rate and respiration rate is readily derived from the overall chemical reaction for aerobic metabolism. The derived relation can be used to show that separation of respiration into growth (g) and maintenance (m) components is not a useful concept. g and m cannot be unambiguously measured or defined in terms of biochemical processes. Moreover, because growth yield calculations from biochemical pathway analysis, from biomass molecular composition, from biomass heat of combustion, and from biomass elemental composition have not included all of the energy costs for biosynthesis, they are not accurate measures of the carbon cost for plant growth. Improper definitions of growth-respiration relations are impeding the use of physiological properties for prediction of plant growth as a function of environmental variables.     

An Experimental Study of Cell and Nuclear Growth and Their Relation to Cell Diversification within a Plant Tissue

Roots of Zea mays were grown for four days in a solution of colchicine that inhibits cell division. During this period the amount of cell growth and nuclear DNA replication was measured in different regions of the root cap. The rates at which cell volume and nuclear DNA content double are similar in the first cell-tier of the cap (the meristematic stem-cell) but in more distal cells the rate of cell growth outstrips the rate of nuclear DNA increase. It is suggested that the degree of coordination between cell and nuclear growth regulates meristematic activity and can influence the onset of cell differentiation.
The pattern of endopolyploidy changes in the different regions of the colchicine-treated root cap. It is suggested that the degree of endopolyploidy normally characteristic of cells at particular locations within this tissue is not a response to a positional signal alone; it is more likely to be due to some rate-limiting control of DNA synthesis.     

The Relation Between Growth of Gastrodia elata Protocorms and Fungi

Armillaria mellea penetrated protocorms from seed germination and vegetative multiplication corms of Gastrodia elata with rhizomorph. At beginning, they formed a hypha passing road and a hypha flow in the inner cells of cortex, and then, they both penetrated inside of large cells and penetrated outside of cortical cells. Gastrodia elata seeds depended on digesting Mycenct osmundicola etc gain nutrition to germinate at the stage of sexual reproduction, but its corms of vegetative multiplication must be penetrated by Armillaria mellea obtaining nutrition for normal growth at the stage of vegetative propagation.     

RBSDV在玉米叶脉细胞内的侵染状态与灰飞虱传毒活力的关系

根据水稻黑条矮缩病毒(RBSDV)侵染玉米(Zea mays L.)的症状发展过程先后取叶脉做超薄切片,在透射电镜下观察病毒在细胞内的侵染状态,并在取样前用灰飞虱无毒若虫进行饲毒和传毒试验.结果显示RBSDV侵入玉米叶细胞后先出现在细胞壁附近,个别粒子似与胞间连丝相连;细胞质内产生病毒基质,病毒粒子先增殖并分布其周边,后向病毒基质内扩展;当病毒粒子布满病毒基质后在细胞质中出现直径约90nm的管状结构,病毒成串排列在该管状结构中;随后管状结构逐渐消失,最终形成晶格状聚集排列.用灰飞虱无毒若虫在细胞内病毒基质出现和病毒增殖期饲毒的,到成虫时分别有2.93%和7.83%个体传毒率;在细胞内病毒成串分布于管状结构和晶格状聚集排列期饲毒的,到成虫时均不能传毒.     

RBSDV在玉米叶脉细胞内的侵染状态与灰飞虱传毒活力的关系

根据水稻黑条矮缩病毒(RBSDV)侵染玉米(Zea mays L.)的症状发展过程先后取叶脉做超薄切片,在透射电镜下观察病毒在细胞内的侵染状态,并存取样前用灰飞虱无毒若虫进行饲毒和传毒试验。结果显示RBSDV侵入玉米叶细胞后先出现在细咆壁附近,个别粒子似与胞间连丝相连;细胞质内产生病毒基质,病毒粒子先增殖并分布其周边,后向病毒基质内扩展;当病毒粒子布满病毒基质后在细胞质中出现直径约90nm的管状结构,病毒成串排列在该管状结构中;随后管状结构逐渐消失,最终形成晶格状聚集排列。用灰飞虱无毒若虫在细胞内病毒基质出现和病毒增殖期饲毒的,到成虫时分别有2．93％和7．83％个体传毒率;在细胞内病毒成串分布于管状结构和品格状聚集排列期饲毒的,到成虫时均不能传毒。     

应加强对单细胞生物分批培养生长曲线中减速期的认识和教学

根据单细胞生物分批培养过程中比生长速率(μ)的变化,其生长曲线分为延滞期、加速期、对数期、减速期、稳定期和衰亡期6个时期.与其他生长时期相比,在减速期生物的生长、基质的利用、产物的合成和基因表达谱等方面有显著的不同,并对发酵生产有着重要作用.然而,长期以来,对减速期的认识和教学相当薄弱,亟需加强对减速期的认识和教学.     

On the Relation Between the Effects of Auxin on Growth, pH and Potassium Transport

The relation between the effects of auxin on growth, pH and potassium transport in hypocotyl segments of Helianthus annuus was studied. In a solution containing 20 mM Na₂SO₄ auxin-induced growth was accompanied by an auxin-induced pH drop in the medium. (NH₄)₂SO₄, at the same concentration, brought about an almost complete abolishment of the effect of auxin on the pH. The magnitude of auxin-induced growth was, however, only slightly reduced. This result does not confirm the hypothesis according to which the action of auxin on growth is a result of its effect on the pH. In a solution containing 2 mM sodium phosphate buffer an inhibitory action of IAA on the release of potassium from the tissue was observed. Addition of 20 mM Na₂SO₄ to the medium brought about a complete abolishment of this effect. The magnitude of auxin induced pH drop was, however, similar in the two treatments. It was concluded that, although under suitable experimental conditions, a close relationship may exist between the effects of auxin on pH on K⁺ transport, the coupling between the two phenomena is not obligatory.     

培养基成分对东北红豆杉细胞生长和紫杉醇产量的影响

在东北红豆杉(taxuscuspidate)细胞培养物的基本培养基中加入30mg@L-12.4-D,可以提高细胞培养物的生长量,其相对最高生长量可以达到85.999mgFW/gFW@d;培养基中加入活性炭粉末lg@L-1,可以克服植物细胞生长过程中的褐化问题;适当种类及含量的生长调节剂的加入:6-BA0.5mg@L-1+KT2mg@L-1,可以使植物细胞合成和积累相对较多的紫杉醇(Taxol)。 Abstract:The growth quantity of Taxus Cuspidate's cell culture materials can be increased and the highest quantity will amount to 85.999 mgFW/g·FW·d·if We put 2,4-D (30rog·L-1 )into the basic cuhure medium of it; The difficulty of foxiness during the plants growing process can be overcome if we add acive carbon powder(lgL-1)into the culture medium; The plant cell can synthetize and gather more Taxol comparatively with the addition kf proper and amount of growth regulators:6-BA(0.5mg·L-1) + KT2.     

培养基成分对东北红豆杉细胞生长和紫杉醇产量的影响

在东北红豆杉（taxus cuspidate)细胞培养物的基本培养基中加入30mg.L^-12.4-D,可以提高细胞培养物的生长量,其相对最高生长量可以达到85．999mgFW/gFW.d;培养基中加入活性炭粉末1g.L^-1,可以克服植物细胞生长过程中的褐化问题;适当种类及含量的生长调节剂的加入：6－BA0．5mg.L^-1＋KTmg.L^-1,可以使植物细胞合成和积累相对较多的紫杉醇（Taxol).     

Relation between Ion Accumulation of Salt-Sensitive and Isolated Stable Salt-Tolerant Cell Lines of Citrus aurantium

Four selected NaCl-tolerant cell lines of Sour orange (Citrus aurantium) were compared with the nonselected cell line in their growth and internal ion content of Na⁺, K⁺, and Cl⁻ when exposed to increasing NaCl concentrations. No difference was found among the various NaCl-tolerant cell lines in Na⁺ and Cl⁻ uptake, and all these cell lines took up similar or even larger amounts of Na⁺ and Cl⁻ than the NaCl-sensitive cell line. Exposure of cells of NaCl-sensitive and NaCl-tolerant lines to equal external concentrations of NaCl, resulted in a greater loss of K⁺ from the NaCl-sensitive cell line. This observation leads to the conclusion that growth and ability to retain high levels of internal K⁺ are correlated. Exposure of the NaCl-tolerant cell lines to salts other than NaCl resulted in even greater tolerance to Na₂SO₄, but rather poor tolerance to K⁺ introduced as either K₂SO₄ or KCl; the latter has a stronger inhibitory effect. The NaCl-sensitive cell line proved to be more sensitive to replacement of Na⁺ by K⁺. Analyses of internal Na⁺, K⁺, and Cl⁻ concentrations failed to identify any particular internal ion concentration which could serve as a reliable marker for salt tolerance.     

Optimum Membrane Structures for Growth of Coliform and Fecal Coliform Organisms

The purpose of this study was to determine the optimum membrane filter structure and characteristics for recovery of coliform organisms. Additionally, other factors such as sterilization method and membrane composition were examined. Fecal coliform growth tests with varied samples indicated that the most critical factor in recovery was surface pore morphology and not other factors previously suspected. Fecal coliform counts showed a dramatic increase, with increasing surface opening sizes. Membrane structures with surface openings large enough to surround the entrapped bacteria are required for optimum growth of fecal coliform organisms. Maximum fecal coliform recoveries are obtained using membranes composed of mixed esters of cellulose exhibiting a surface opening diameter of 2.4 μm and a retention pore size of 0.7 μm.     

中度嗜盐或耐盐放线菌生长对阴离子选择性研究*

长期以来Cl^-被作为主要阴离子来分离和培养中度嗜盐放线菌,但是盐湖中还含有NO3^-、SO4^2-、CO3^2-和HCO3^-等阴离子。培养基中只加入含有Cl^-的盐,不能完全模拟出自然界的环境,因此对中度嗜盐或耐盐放线菌的研究会有一定的限制。实验通过研究部分中度嗜盐或耐盐放线菌菌株生长对阴离子的选择影响,结果发现中度嗜盐或耐盐放线菌对部分阴离子如NO3^-和SO4^2-没有太大的选择性,Cl^-可以被NO3^-和SO4^2-所代替;但有些阴离子如CO3^2-和HCO3^-仅对拟诺卡氏菌属(Nocardiopsis)影响较小,对盐碱环境中的其他属的放线菌,如普氏菌属(Prauserella)、链单孢菌属(Streptomonospora)、糖单孢菌属(Saccharomonospora)等影响较大。     

The Size of Cells and Organisms in Relation to the Evolution of Embryophytes

Abstract: The earliest O₂-_-evolvers were marine cyanobacteria (3.5 billion years ago) with marine eukaryotic phototrophs from 2.0 billion years ago. These organisms were, and are, poikilo-hydric, i.e., cannot remain hydrated when exposed to a desiccating atmosphere (as can occur for intertidal benthic algae and cy anobacteria at low tide). The smallest marine primarily poikilo-hydric O₂-_-evolvers are close to the lower size limit imposed by non-scaleable components such as minimum genome size and constant membrane thickness, with cyanobacterial unicells 0.65 μn in diameter and eukaryotic unicells 0.95 μm in diameter. The largest (multicellular) marine primarily aquatic poikilohydric O₂-_-evolvers are brown algae at least 60 m long and over 100 kg fresh mass; there are no obvious constraints on the max imum size of such organisms. In freshwaters the size range for primarily poikilohydric O₂-_-evolving organisms is smaller, due to the absence of very large organisms. An even smaller size range characterizes terrestrial algae and cyanobacteria which have occurred for about 1 billion years. Desiccation-tolerant cyanobacterium and algae (intertidal, freshwater, terrestrial) are at the lower end of the size ranges. Embryophytic terrestrial O₂-_-evolvers arose some 450 million years ago and were than all poikilohydric and (probably) desiccation-tolerant. Embryophytic defining structural features re quire organisms of at least 100 μm equivalent spherical diameter for both gametophyte and sporophyte phases. Primarily poi kilohydric embryophytes are not more than 1 m tall as a result of a mechanistically mysterious size limit for desiccation-tolerant organisms. Homoiohydric embryophytes evolved some 420 mil lion years ago in the sporophyte phase (later to become the dominant terrestrial vegetation) and possibly in the gameto phyte phase (although no such homoiohydric gametophytes are known today). The homoiohydric features of gas spaces, stomata, cuticle, endohydric water conducting system and water and nutrient uptake structures require an organism at least 5 mm high; this has implications for the minimum size of mega-spores and seeds. The tallest homoiohydric plants are (or were within historic times) 130 m high, with height constrained by re source costs of the synthesis and maintenance of the mechanical and water conduction systems, andbr of xylem water trans port. Secondarily poikilohydric embryophytes in aquatic, or very damp terrestrial, habitats are derived from homoiohydric plants; they retain most homoiohydric features but are not functionally homoiohydric. The smaller secondarily poikilohydric plants are less than one tenth of the size of the smallest functionally homoiohydric plants.     

Association Between Serum Magnesium and the Prevalence of Kidney Stones: a Cross-sectional Study

Biological Trace Element Research - Kidney stones, a painful and costly disease, have become a public health problem worldwide. The aim of this study was to evaluate the association between serum...     

Ion Transport in Suaeda maritima: Its Relation to Growth and Implications for the Pathway of Radial Transport of Ions across the Root

The ion relations of the halophytc Suaeda maritima are described.When plants grew in 340 mol m^–3 sodium chloride (—1•76MPa) leaf solute potentials decreased, and were sustained around—2•5 MPa Inorganic ion concentration (mostly of sodiumchloride) accounted for this. Comparable shoot ion concentrationsof potassium, nitrate and sulphate occurred when plants grewon different salinity types characterized by these ions. Netsodium transport and shoot sodium concentration increased dramaticallywith increases in external sodium chloride concentration upto 85 mol m^–3; thereafter, further increases in externalsodium chloride concentration had relatively little effect uponeither shoot sodium concentration or upon net transport of sodiumto the shoot. The net transport of sodium plus potassium onlydoubled when the external concentration of sodium plus potassiumincreased from 24 to 687 mol m^–3 Shoot ion concentrationswere remarkably constant with time, external concentration andsalinity type. The membrane flux rates and symplasmic ion concentrations neededto sustain the observed net transport of sodium (of some 10mmol g^–1 dry wt. of roots d^–1) are calculated fromanatomical and stereological data for the root system of thisspecies. The minimum net sodium chloride flux to load the symplasmwould be 260 nmol m^–2s^–1 if the whole cortical andepidermal plasmalemmal surface area were used uniformly, butthe flux rate required would be 3000 nmol m^–2s^–1if uptake took place only at the root surface. A flux rate ofat least 1000 nmol m^–2s^–1 is needed between symplasmand xylem. The symplasmic concentration of NaCl would be atleast 80 mol m^–3. It is argued (1), that both symplasmicand xylem loading are likely to be passive processes mediatedby ion channels rather than active carriers, (2), that net iontransport at 340 mol m^–3 sodium chloride is close to themaximum which is physiologically sustainable and (3), that growthof this halophyte is limited by NaCl supply from the root. Key words: Suaeda maritima, halophyte, salinity, roots, radial ion transport     

蛋白质折叠速度与其拓扑结构关系的研究

以6种不同的方式来定义蛋白质内存在的接触,进而运用分子动力学模拟等不同方法,对10个小蛋白进行分析,研究了不同的接触定义及不同的拓扑参数计算方法下,蛋白质的折叠速度与其拓扑参数的关系.结果表明,用含主链重原子的方式定义接触,所计算的拓扑参数与蛋白质折叠速度的相关性较好;用含侧链原子的方式定义接触,得到的拓扑参数与β型蛋白质的折叠速度的相关性较好.对不同的蛋白质,其拓扑结构与相应折叠速度间的相关程度不同。     

Dust Ion Acoustic Solitary Structures at the Acoustic Speed in the Presence of Nonthermal Electrons and Isothermal Positrons

Plasma Physics Reports - The Sagdeev pseudo-potential technique and the analytic theory developed by Das et al. [J. Plasma Phys.78, 565 (2012)] have been used to investigate the dust ion acoustic...