摘要:

AbstractThe light saturation curves for photosynthesis inLycopersicon esculentumhave been studied for a yellow‐green mutation and for hormone treated plants. Comparisons have been made between saturation point and the size of the photosynthetic unit in these plants. These data suggest a function in the regulation of photosynthetic rate

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1974.tb03682.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractWater uptake of root systems ofPhaseolus vulgariswas measured in a Scholander pressure cylinder at a constant pressure. Water uptake rises gradually till a steady state is reached after 15 to 60 minutes. This time course can be described as a transport process with the property of a self‐induction. The latter was not affected by temperature. It is concluded that the property of self‐induction is located in the cytoplasm or at the interface between cytoplasm and plasmalemma of the endodermal cells. It is suggested that cytoplasmic streaming controls the time course of water transp

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1974.tb03683.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractThe extent of redistribution in apple was described by calculating the fruit/leaf ratio of the cation content. It was found that the redistribution diminishes in the sequence K>Mg>Ca ∼ Mn. These results are more or less in agreement with those found elsewhere.Investigations were made to see whether it was possible to account for the differences in redistribution by the phloem by means of the solubility of these cations in the sieve tube sap. As model plantsYucca flaccidaandRicinus communiswere used, plants from which it was possible to obtain phloem sap in a rather pure state. It was found that the addition of potassium and magnesium as a chloride in the usual investigated range of concentrations did not give precipitation. With calcium and manganese, however, a precipitate soon occurred. Manganese was demonstrated to be less soluble than calcium. For Ricinus the maximum amount of calcium and manganese the sieve tube sap could contain before precipitation set in was higher than for Yucca sap.The results confirm the possibility that the redistribution of the different cations in the plant can be relatedinter aliato their solubility in the sieve tube sap.It was also found that the calcium in the phloem sap is present in ionic condition. Thus the normal laws of solubility should be applicabl

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1974.tb03684.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract1In a mendelian (sr3) and an uniparental (sr35) streptomycin resistant mutant ofChlamydomonas reinhardithe influence of streptomycin on protein synthesis on the chloroplast and cytoplasmic ribosomes was investigatedin vitro. Hetero‐, mixo‐ and phototrophic agar cultures and heterotrophic liquid cultures were used.2Protein synthesis on the cytoplasmic ribosomes, measured by the activity of glyceraldehyde‐3‐phosphate: NADP dehydrogenase (EC 1.2.1.9), was not inhibited, but rather stimulated by streptomycin.3Protein synthesis on the chloroplast ribosomes of sr3, measured by the activity of ribulose‐1,5‐diphosphate carboxylase (EC 4.1.1.39), was greatly inhibited by streptomycin, especially in hetero‐ and mixotrophic cultures. In sr35the chloroplast ribosomes were resistant to streptomycin.4Heterotrophically grown cultures of sr3and of a streptomycin‐sensitive strain are yellow in the presence of streptomycin and form no or only reduced thylakoids on solid media. But 70‐S organelle‐ribosomes are present in a normal amount.5The relationship between chloroplast protein synthesis and thylakoid for

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1974.tb03685.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractVarying light intensity and temperature treatments were applied to whole plants, or to the leaves, or to the flower buds of ‘Baccara’ roses. The effect of these treatments on flower dimensions and pigmentation of the petals was examined.Cooling only the leaves had no effect; cooling only the buds enhanced both bud weight and pigmentation, but the effect was less marked than when the whole plant was cooled. Reducing plant temperature by misting with desalinated water enhanced both pigmentation and flower size.Darkening of only the leaves, or their removal, resulted in an inhibition of the pigmentation and also in a decrease in bud weight. Darkening of only the flower bud did not affect either pigmentation or bud weight, but caused bud elongation. It is suggested that light intensity and temperature affect flower growth and pigmentation via their effects on the availability of sugars in the flower

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1974.tb03686.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractGrowth and pigmentation of ‘Baccara’ rose buds were followed. Petal elongation mainly occurred during a short period of time after the flowering shoot had stopped elongating. Approximately 90% of the flower pigments were synthesized during a short period lasting from the time the bud was 75% to the time it was 100% of its diameter at opening time. Petal growth continued after this period so that the pigments in the petal were “diluted”. Heat stress applied to whole plants or to flower buds only, or a short duration of low light intensities caused “blueing” of the petals when these conditions prevailed during the period of maximum pigmentation. Stress conditions prior to this period or following it, had no effect. We suggest that stress conditions such as high temperature or low light intensities reduce the availability of sugars. When this occurs at the time of maximum pigment production, a fall in the level of pigment occurs, which results in the “blueing

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1974.tb03687.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractRoots produce cytokinins, which could be generated from the catabolism of transfer RNA. To prove such a hypothesis, the half‐life of sRNA from primary roots of corn was measured. The shortest half‐life was estimated to be 3 days. Depending on growth, cells at the root tips are “moving” out of the growing region and become differentiated cells. Therefore the highest label at the root tip during the pulse incubation is moving backwards during the chase incubation. Prolonged chase increases the half‐life of sRNA successively, possibly due to decreasing metabolic activities of the originally labe

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1974.tb03688.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractIndoleacetic acid, tryptophan and indole promote growth of pith tissues of tumorousNicotiana glauca×N. langsdorffiiamphidiploïd hybrid, but only indoleacetic acid gives the potentiality of continuous development to the tumorous tissues after some days of contact on a medium without growth substances. In combination with 6‐benzylaminopurine, tryptophan and especially indole are promoting substances like auxin for the non‐tumorous pith tissues of tobacco, and allow a considerable organoge

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1974.tb03689.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractA technique is described whereby active preparations of glutamic dehydrogenase (GDH) and glutamic‐oxaloacetic transaminase (GOT) can be obtained from all apple tree tissues using a hand‐operated coffee mill. The amount of insoluble polyvinylpyrrolidone required and the composition of the extractant have been investigated together with the degree of replication obtained and the stability of the resultant extracts.After extraction of all tissues the proportion of both GDH and GOT found in the supernatant was far greater than that in the mitochondria. Addition of calcium and some other metal ions to the assays resulted in some increase in GDH but had no effect on GOT activity. With crude extracts the effect of added calcium was small but after ultrafiltration or acid precipitation it was greatly increased.The co‐factors NADH, NADPH and NAD were all active with GDH in extracts of apple leaves, stem bark and roots. No activity was found with NADP. In the presence of added calcium ions the ratios of activity NADH:NADPH and NADH:NAD were approximately 10:1 and 20:1 respectively.The seasonal variations in specific activity of GDH and GOT in apple leaves, stem bark and wood, and old and young roots were determined separately. The highest GDH activities were found in the leaves in October and in the stem bark in May, while in other tissues activities were generally higher in winter than in summer. The seasonal patterns for GOT activity were very similar to those for GDH except that in the leaves the level changed little through the year.The results are discussed in relation to published work on these enzymes in other plants and to their possible role in the apple

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1974.tb03690.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractThe specific activity of isocitrate lyase rapidly increased in the megagametophytic tissue of cold‐stratified seeds of ponderosa pine (Pinus ponderosaLaws) prior to and after germination. When the embryo was removed at germination, isocitrate lyase activity continued to develop. However, in the total absence of the embryo, only a small increase in the specific activity of the enzyme was observed. The development of the enzyme was inhibited by cycloheximide, actinomycin D and abscisic acid.The embryo produced an unidentified factor which enhanced the development of isocitrate lyase activity in the megagametophytic tissue. This embryo factor could not be replaced by the hormones indoleacetic acid (IAA), gibberellic acid (GA3) or benzylaminopurine (BA). Indoleacetic acid had little effect upon enzyme development. Gibberellic acid and benzylaminopurine inhibited isocitrate lyase development in the megagametophytic tissue of the see

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1974.tb03691.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY