摘要:

AbstractRespiratory Activity in Stem, Branches and Leaves of Evergreen Trees in Tropical Rain Forest and of Deciduous Trees in Temperate Climate.— Reduced to the same temperature, the respiratory activity of different parts of tropical rain forest trees and of corresponding parts of temperate deciduous trees is approximately the same. In particular, the leaf‐blades of Danish deciduous trees and of tropical rain forest trees from the lowland of Côte d'Ivoire (57° north. lat.) have nearly the same respiratory activity at 20°C: the blades of the extreme shade leaves about 0.1 mg CO2, those of the extreme sun leaves about 0.8 mg CO2per 50 cm2(one side only) per hour at 20°C. This is in accordance with the fact that the blades of shade leaves, respectively Sim leaves, of the tropical rain forest trees are built in the same way as the blades of deciduous trees in our temperate climate. The respiratory activity shows that they have the same “concentration” of living cells, the same “concentration” of active plasma.The respiratory activity of trunk and branches depends mainly on three factors: diameter of the stem‐section or branch‐section, nutritional condition, and temperature. The respiratory activity of trunk and branches of hardwoods in temperate climate is also dependent on the season. The estimations on stems and branches from the temperature trees were made In July–August. There was in most cases a remarkable agreement in respiratory activity between temperate and tropical hardwoods: Branches with a diameter of about 0.5–2 cm have a respiration of about 70–100 mg CO2per kg fresh weight per hour at 20°C. Trunk sections with a diameter over 20 cm have a respiratory activity of about 3–5 mg CO2, per kg fresh weight per hour at 20°C. In the older parts of a stem most of the cells are dead. The agreement in respiratory activity probably means that the “concentration” of living cells in the older parts of the stem of tropical an

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07844.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe effect of cytokinins and gibberellic acid on the inhibition of growth and α‐amylase synthesis by germination inhibitors was investigated in intact and embryoless seed halves. The cytokinins, kinetin and benzyladenine, effectively reversed the inhibition of coleoptile growth and α‐amylase synthesis by abscisic acid and courmarin in barley seed. An antagonism between cytokinins, kinetin and benzyladenine, effectively reversed the inhibition of coleoptile growth and α‐amylase synthesis by abscisic acid and coumarins in barley seed. An antagonism between cytokinins and germination inhibitors was also shown in root growth. Abscisic acid inhibited coleoptile growth to a greater extent than the root growth while the opposite held true in the case of coumarin.The apparent increase in coleoptile growth and α‐amylase synthesis by gibberellic acid plus abscisic acid (or coumarins) over abscisic acid (or coumarin) appears to be a result of the overall stimulation of growth and metabolism by exogenous gibberellic acid and probably does not involve an interaction of gibberellic acid with the inhibitors. Gibberellic acid reversed root inhibition to some extent.Abscisic acid inhibition of gibberellic acid induced α‐amylase synthesis in the embryoless endosperm was not reversed by excess gibberellic acid or kinetin Cytokinin reversal of inhibition of growth and enzyme synthesis probably depends on some factor(s) in the embryo. Cytokinin reversal of inhibitor action leading to enzymen synthesis and growth may be at the level of genome or at the site pr

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07845.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractSugar maple (Acer saccharumMarsh.) seedlings were grown in a nursery for three years in 13, 25, 45 and 100 per cent of full daylight. During the third year of growth, the rates of their apparent photosynthesis and respiration were measured periodically with an infra‐red gas analyzer at various light intensities and normal CO2concentration. In addition, the rates of apparent photosynthesis of a single attached leaf of the same seedlings were measured at saturating light intensity, hut varying CO2concentrations.An increase in the light intensity in which seedlings were grown had no effect on their height or mean leaf area, hut resulted in thicker leaves, an increase in the total leaf area per seedling due to an increase in the number of leaves, an increase in the dry weight especially of roots and a decrease in the chlorophyll content of leaves.Throughout the growing season seedlings grown in full daylight, as compared with those grown in lower light intensities, had the lowest rates of apparent photosynthesis measured at standard conditions (21,600 lux light intensity and 300 ul/l of CO2), when this was expressed per unit leaf area, hut the highest rates on a per seedling basis. Thus dry matter production attained at the end of the growing season correlated positively with the photosynthetic rate per seedling, but not per unit leaf area. The rates of apparent photosynthesis of seedlings grown at lower light intensities were more responsive to changes in light intensity or CO2concentration than those of seedlings grown in full daylight intensit

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07846.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractA chemically defined medium is desirable for nutritional studies and is frequently necessary for biochemical investigations. Several defined media are available for use with tissue and cell cultures from dicotyledonous plants. A fully defined medium has now been developed for cell suspension cultures from sugarcane. Prior to this, the only medium successfully used for cell cultures of monocotyledonous plants was a modification of Straus' synthetic medium (used to grow cell suspensions of corn).Cell suspension cultures from sugarcane stalk parenchyma, originally established in complex media containing coconut milk or yeast extract, can be grown in this synthetic medium, which consists of inorganic salts, vitamins, sucrose, 2.4‐dicliloropheuoxyacetic acid, and a mixture of 13 amino acids. The most important of the amino acids are arginine aspartic acid, and glutamic acid. This simplified medium wilt aid in the investigation of the unusual and important role of arginine in sugar‐cane growth and metabol

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07847.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe chemotactic response of the mitospores and meiospores ofAllomyces macrogynusand A.abusculato casein hydrolysate was shown to he caused by the combined action of leucine and lysine in the hydrolysate. The testing was done by counting the zoospores that attached to a membrane through which substances diffused downward. The action of leucine and lysine was shown to be synergistic and to be specific for the L, forms. The optimum concentration above the membrane was 5 × 10‐2Mfor each amino acid. An effect was detectable down to approximately 10‐55M. The addition of L‐proline to the mixture increased the response. Proline in combination with leucine caused good attachment, although less than that by leucine and lysine, of the zoospores ofA. arbusculabut not of those ofA. macr

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07848.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe changes in the activity of enzymes hydrolyzing starch were studied. Enzymes were extracted from the leaves ofStellaria media. Enzyme activity seemsto beconcentrated in the chloroplasts. Beta‐amylase has been identified as the main enzyme hydrolyzing starch in these leaves.WhenStellaria mediaplants are left in continuous illumination after a normal light‐dark‐rhythm), beta‐amylase activity remains essentially unchanged for some time. Alter an Illumination of 24–27 hours the activity suddenly increases. This phenomenon occurs at about the same time as the rapid disintegration of starch previously accumulated in the chloroplasts. In the light of present‐day knowledge the increase in the activity cannot b

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07849.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Abstractδ‐Aminolevulinic acid supplied to dark grown isolated leaves or wheat causes an accumulation of protochlorophyllide which is only partly transformed to chlorophyllide α in continuous light At the same time a considerable photodestruction of both pigments takes place. By a suitable combinations of short lights flashes and dark periods it is possible, however, to obtain at least double the amount of the protochlorophyllide transformed without photodestruction. The transformation isshown to be dependent on the dark interval between the light flashes. Possible connections with the formation of the protein part of the protochlorophyllide holochrome are discus

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07850.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractActivities of barley peptide hydrolases A (acidic peptidase) and H (neutral peptidase) were examined in the growing embryo and in the embryoless tissues of Himalaya barley incubated for 70 hours. Tissues examined were roots, shoots, embryo residue (scutellum + seutellar node + coleorhiza) and the embryoless portion of the kernel. Activity of the hydrolase A increased mainly in the embryo residue during 0 to 30 hours but little thereafter. Activity of hydrolase B increased mainly in the embryo residue but did so linearly over the 70 hour period. A small linear increase occurrence in the embryoless portion during this lime.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07851.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe incorporation of uniformly labelled [14C] cytidine into the nucleic acids was studied in root tips ofVicia faba.Cytidine was found to be incorporated into RNA and DNA and the specific activities of the individual mononucleotides were deter‐ mined. The pyrimidine nucleotides were degrade and the ratio between the specific activity of the pentose and the specific activity of the base was determined for each nucleotide.CMP of RNA and deoxy CMP of DNA bad almost the same pentose: base ratios as The cytidine added to the incubation medium. It was concluded that the administered cytidine or a derivative of it was reduced to the corresponding deoxycytidine compound without breakage of the bond between pentose and base.[14C)‐cytidine was transformed to UMP of RNA with some loss of radioactivity from the pentose and had almost the same pentose: base ratio as deoxy TMP of DNA. This indicates that the formation of thymidine phosphates involved The reduction of a uridine compound.Furthermore the incorporation of14C‐labelled thymidine, deoxyadenosine and deoxyguanosine into DNA was studied. Deoxyguanosine was found to be incorporated only to a slight extent. This finding has been discussed in relation to previous re

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07852.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractAgar‐grown cultures of tobacco pith tissue (Wisconsin 38) were incubated in the dark or in the light for 36 days. With 1 μM indole‐3‐acetic acid (IAA) in the medium, considerable differentiation, including organogenesis occurred in the light, but not in the dark. Such photoenhancement of differentiation did not occur when 2.4‐dichlorophenoxy acetic acid (2,4‐D) or naphthalene acetic acid (NAA) was substituted for IAA. Blue light of greater than 12 days duration was responsible for the photoenhancem

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07853.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY