Investigations on Growth and Metabolism of Plant Cells: I. New Techniques for the Investigation of Metabolism, Nutrition and Growth in Undifferentiated Cells

This paper describes a technique for comparisons of the metabolismof rapidly growing and non-growing tissues. The requisite conditionsfor such studies are discussed. Active tissue growth is obtainedby using aseptic conditions and a complete nutrient medium withcoco-nut milk added. Rapid diffusion and gas exchange is obtainedby using special tubes in which the tissue and medium are rotatedin the presence of a large volume of air. Modifications aredescribed which enable various types of metabolic treatmentto be used, including the use of tracer carbon. The tissue principallydescribed is carrot phloem, but various other possibilitiesincluding the use of micro-organisms are envisaged.     

Investigations on Growth and Metabolism of Plant Cells: IV. Evidence on the Role of the Coconut-Milk Factor in Development

By the carrot-assay method it has been shown that the wateryendosperm of coconut contains the growth-promoting coconut-milkfactor at all stages of development. Some activity is shownby the parts of the immature embryo but not by the solid endosperm. Sources of analogous activity are in the endosperm of Zea maysin the milk stage, the gelatinous content of immature fruitsof Fuglans regia, and the young gametophyte of Ginkgo biloba.The data for other cases examined suggest that the materialdevelops best in nutritive tissues associated with delayed embryodevelopment.     

Investigations on the Growth and Metabolism of Plant Cells: V. Tumorous Growth in Relation to Growth Factors of the Type found in Coconut

1. It has been shown that aqueous extracts of plant tumours,induced by Agro-bacterium tumefaciens (Smith and Townsend) onBryophyllum and Kalanchoe, will act in place of coconut milkusing the tissue-culture procedures previously described inthis series of papers. 2. In a large number of experiments it has been shown that tumoursof this kind yield extracts which have a growth-promoting effectsimilar to that of coconut milk. This effect may be enhancedby, though it is distinguishable from the effects of, addedcasein- hydrolysate in the basal medium. The activity of thetumour extracts was consistently greater than the activity ofextracts of stems and leaves of the same plants and of normal,non-tumorous plants. 3. Partial fractionation of the tumour extracts has shown thatactivity was concentrated in the alcohol extracts, and to alesser extent in the water extracts. Activity was completelylacking in the ether extracts. 4. The effect of coconut milk, which is replaceable wholly orin part by tumour extracts, is primarily an effect on cell divisionin the carrot tissue. 5. The bearing of these results on tumorization in plants isdiscussed.     

Investigations on the Growth and Metabolism of Plant Cells: II. Variables affecting the Growth of Tissue Explants and the Development of a Quantitative Method using Carrot Root

This paper describes the technique of growing small discs ofcarrot phloem in pure culture and with the precautions necessaryto standardize the rate of growth at the highest practicablelevel. It deals with the procedure necessary to remove replicatesamples of the material, with variability along the radial andlongitudinal axes of the carrot, and with the regulation ofthe culture conditions. Evidence is adduced of the existence of a ‘staling’factor in crowed cultures.     

Temperature and the Growth of Plant Cells

In cell elongation, the juvenile cell vacuolates, takes up water, and expands by irreversible extension of the growth-limiting primary walls. This process was elaborated analytically by Lockhart in the mid-1960s. His growth equation does not, however, include the influence of the environmental temperature at which cell growth takes place. In this article we consider a phenomenological model including temperature in the equation of growth. Also, by introducing the possible influence of growth regulators treated here as external perturbations, linear and nonlinear solutions are found. A comparison of experimental and theoretical results permits qualitative and quantitative conclusions concerning change in the magnitude of the cell wall yielding coefficient Φ as a function of both time and temperature (with or without external perturbations), which has acquired reasonable values throughout.     

Investigations on the Glycerol Metabolism of Lactobacilli

S ummary . The glycerol metabolism of homofermentative and heterofermentative strains of Lactobacillus obtained either from Culture Collections or isolated from sausages has been investigated.
The results show that the homofermentative lactobacilli ( Thermobacterium and Streptobacterium ) produce mannose phosphate which is then metabolized to lactic acid and other byproducts.     

Thermal Inactivation of Plant Growth: Effects on Cotyledon Metabolism

Temperature exposures which normally decrease growth of Pisum sativum seedlings by 50 % were found to be lethal in plants whose cotyledons were removed. Utilization of the two major reserves, starch and protein, decreased at high temperatures. However, the two enzymes responsible for their hydrolysis were thermostable. It appears that the influence of high temperatures on seedling growth is not due to direct effects of temperature on cotyledon metabolism, but rather indirectly through the axis.     

Differential Effect of Ribosome-Inactivating Proteins on Plant Ribosome Activity and Plant Cells Growth

The effect of ribosome-inactivating proteins (RIPs), eithersingle-chain or toxins, was studied on plant ribosomes. RIPsdid not affect ribosomes from their own plants, while inhibitingto a variable extent protein synthesis by heterologous plantribosomes. Ricin stimulated and PAP—S inhibited the growthof carrot cells in culture. Key words: Plant ribosomes, Ribosome-inactivating proteins, Protein synthesis, Ribosome specificity, Plant cell cultures     

Further Investigations of Liposoluble Fluorescent Compounds in Senescing Plant Cells

The accumulation of liposoluble fluorescent compounds with excitationand emission fluorescent maxima in the bands of 350–370nm and 410–440 nm respectively has been observed in thedegrading (the late stationary phase) blue-green algae Anabaenavariabilis K?tz and Anabaena cylindrica Lemm. cells, in thedark-senescing cotyledons from Phaseolus vulgaris L., and inmore than 1-year-old leaves of evergreen plants (Ligustrum japonicumThunb. and Osmanthus fortunei Carr.)- Spectral and chromatographicproperties of the compounds are rather similar to those previouslydescribed in the cells of other senescing plant species. Therole of lipid peroxidation in the formation of fluorescent pigmentsand in the ageing of plant cells is discussed. Key words: Fluorescent pigment, Anabaena sp, Senescence     

Protein Kinase Activity of in vitro Cultured Plant Cells in Relation to Growth and Starch Metabolism

Taking tetcyclacis, a norbornenodiazentine derivative, as an example, the influence of a growth retardant on the shoot growth of sunflower, soybean, and maize seedlings grown and treated in hydroculture was investigated. In detail, the reduction in the length of various shoot sections {epicotyl, 1st internode, leaf blade) caused by the retardant was studied. At low concentrations of the retardant (\lt10^-6 M) the shortening effects are substantially attributable to an influence on cell elongation, whereas cell division is inhibited as the concentration increases (τ10^-6 M). A comparison of the effects of tetcyclacis in cell suspension cultures of appropriate plant species showed that also in this system concentrations τ 10^-6 M inhibited cell division growth, i. e. there is comparability of plant/ cell culture regarding the retardant effect on cell division. In contrast to the intact plants, however, cell elongation appears to be of only subordinate importance for the growth of cell cultures, as it has been shown using parsley cell suspension cultures.It is discussed to what extent influencing the gibberellin or sterol biosynthesis by means of tetcyclacis provides an explanation for the concentration-dependent effect on the cell division and cell elongation processes.     

Effect of High Temperature on Plant Growth and Carbohydrate Metabolism in Potato

This study was undertaken to determine the role of sucrose-metabolizing enzymes in altered carbohydrate partitioning caused by heat stress. Potato (Solanum tuberosum L.) genotypes characterized as susceptible and tolerant to heat stress were grown at 19/17[deg]C, and a subset was transferred to 31/29[deg]C. Data were obtained for plant growth and photosynthesis. Enzyme activity was determined for sucrose-6-phosphate synthase (SPS) in mature leaves and for sucrose synthase, ADP-glucose pyrophosphorylase, and UDP-glucose pyrophosphorylase in developing tubers of plants. High temperatures reduced growth of tubers more than of shoots. Photosynthetic rates were unaffected or increased slightly at the higher temperature. Heat stress increased accumulation of foliar sucrose and decreased starch accumulation in mature leaves but did not affect glucose. SPS activity increased significantly in mature leaves of plants subjected to high temperature. Changes in SPS activity were probably not due to altered enzyme kinetics. The activity of sucrose synthase and ADP-glucose pyrophosphorylase was reduced in tubers, albeit less quickly than leaf SPS activity. There was no interaction of temperature and genotype with regard to the enzymes examined; therefore, observed differences do not account for differences between genotypes in heat susceptibility.     

半边结灌注培养中杂交瘤细胞的生长和代谢

考察了半连续灌注培养中ＷｕＴ３杂交瘤细胞在不同灌注速率下细胞生长的动态变化,培养其中主要基质的消耗和代谢物的生成。当灌注速率Ｄ从１．０／升高到２．０／ｄ升高到２．０／ｄ时,乳酸得率系数Ｙｌａｃ／ｇｌｕ降低１８％,氨得率系数Ｙａｍｍ／ｇｌｎ降低４０％,丙氨酸得率系数Ｙａｌａ／ｇｌｎ升高５８％,甘氨酸得率系数Ｙｇｌｙ／ｇｌｎ基本恒定。说明在灌注速率升高的条件下,细胞会调整代谢机制,丙酮酸和过量的谷氨酸     

Studies of the Growth in Culture of Plant Cells

Mitochondria have been isolated from sycamore cells (Acer pseudoplatanusL.) grown in suspension culture, and resemble those of otherplant tissues. Malate, succinate, and NADH are oxidized withrespiratory control. The respiration is partially inhibitedby antimycin A and KCN, but not by amytal and rotenone. Octylguanidine,oligomycin, and uncouplers all affect the coupled respiration. The proportion of the respiration resistant to KCN was foundto change during the life of the culture, being greatest duringthe lag phase and least during the linear phase. The relationshipof these changes in the electron transport pathways to the changingdemand of the culture for phosphorylated and other intermediatesis discussed.     

Regulation of Callose Metabolism in Higher Plant Cells in vitro

Temporary accumulation of callose in suspension-cultured wheat (Triticum timopheevii Zhuk.) cells at the exponential growth phase was correlated with the mitotic index due to the formation of the cell plates in dividing cells. Callose disappeared in expanding cells owing to enhanced activities of endo- and exoglucanases. The exogluconase activity was reduced when the cells were treated with cycloheximide, an inhibitor of protein synthesis. A similar pattern was observed when elicitors experimentally enhanced callose synthesis. Apparently, in such cases, callose behaves as a temporary component repairing the cell wall. We presume that plant cells comprise a universal mechanism for regulating callose synthesis.     

Nitrogen Metabolism, Respiration, and Growth of Cultured Plant Tissue

Critical examination of the amino-acid composition of proteinsin fast-growing and slow-growing tissues reveals only very 8maUdifferences, indicating that some factor other than the amino-acidcomplement is responsible for, or reflects, the great increasein the mass of protein in the fast-growing tissues. Increases in fresh weight and total protein are exactly parallel,indicating that water uptake is an active process associatedwith growth. Respiration, on the other hand, increases far morein the fast-growing over the slow-growing tissues than doestotal protein. A given amount of protein in the fast-growingtissue will support a much greater respiration rate than thesame amount in slow-growing tissue. The incorporation of radioactivity into amino-acids of the proteinin4icates that there are two distinct types: those in whichincorporation is increased in fast-growing tissue much morethan the total protein, and to the same ezte as respiration(notably glutarnic acid, aspartic acid, and threonine); andthose in which the increased incorporation is much nafler, slightlyless than total protein (notably proline and hydroxyproline).It is concluded that there are two n protein fractions: the‘active’ moiety, which is undergoing rapid breakdownd resynthesis, giving rise to much of the CO through oxidationof its residues; a the ‘inactive’ moiety, whichonce synthesized is not reutilized or broken down. It is theformer, or ‘active‘ protein whose synthesis is greatlyincreased in the fast. growing tissues, and it is the pace,rather than the kind, of reactions which differ entiates betweenthe fast- and slow-growing tissues. The entire experimental data are discussed with reference toa number of cur rent theories and investigations. A number ofexperimental observations are noted which admit of interpretationalong the lines here developed.     

Influence of Tomato Plant Mycorrhization on Nitrogen Metabolism,Growth and Fructification on P-Limited Soil

Journal of Plant Growth Regulation - The application of mycorrhizal fungi in agricultural soils as bio-fertilizers is going to be established as an agronomic practice for enhancing crop nutrients...