摘要:

Structural and cytochemical comparisons were made between three peroxisome types in soybean [Glycine max(L.) Merr. cv. Centennial]. Leaf peroxisomes were densely granular organelles with an amorphous nucleoid and were generally located in close proximity to the chloroplasts. Catalase (EC 1.11.1.6) and glycolate oxidase (EC 1.1.3.1) were localized in these peroxisomes although glycolate oxidase was absent from the nucleoid region. Glyoxysomes, present in the etiolated cotyledons, were coarsely granular organelles that were generally in close proximity to lipid bodies. Malate synthase (EC 4.1.3.2), catalase, and glycolate oxidase were present throughout the matrix. Although peroxisomes were found in both infected and uninfected nodule tissue, uninfected interstitial cell peroxisomes were the most developed. These organelles contained a core surrounded by a less electron‐opaque periphery that frequently was in close association with (but distinct from) a network of smooth endoplasmic reticulum. Of the enzymes studied, only catalase and urate oxidase (EC 1.7.3.3) were detected in the nodule peroxisomes. Neither enzyme was detected in the peripheral area of the peroxisome. These data indicate that peroxisomes in the three tissue types have organelle associations, internal structures, enzyme constitutions and packaging that reflect their metabolic difference

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb01205.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Several brassinosteroid (BR) analogues, cholesterol and aldosterone were evaluated for their effectiveness alone and in combination with indole‐3‐acetic acid (IAA) in stimulating ethylene production by etiolated mung bean (Vigna radiataL. Rwilcz cv. Berken) hypocotyl segments. Changing the conformation of the two hydroxyl groups on C‐22 and C‐23 positions from α to β did not greatly reduce the efficiency of these compounds to stimulate ethylene production alone or in combination with IAA. There was little difference in activity observed when the conformation of the methyl group in the C‐24 position was changed from α to β. However, when hydroxyls were deleted from the side chain in the C‐22 and C‐23 positions, the compound was rendered inactive alone or in combination with IAA. The compound was also inactivated by removing the 7‐oxa function on the B‐ring and by substituting an ethyl group for the methyl group in the C‐24 position. Both aldosterone and cholesterol were ineffective in promoting ethylene production. This study shows that very stringent structural features are required for a steroid to have BR‐like activity and to act synergistically with auxin in the promot

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb01206.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

A theory is developed on the assumption that growth of plants is determined by the current amount of nitrogen in the plants. The nitrogen‐growth relation is formalized in the nitrogen productivity concept (amount of biomass produced per amount of nitrogen in the biomass and per unit of time), which is essentially a constant for a given species under fixed environmental conditions. A number of results follow for increases in whole plant biomass: (A) The relative growth rate is a linear function of the internal nitrogen concentration. (B) The maximal relative growth rate uniquely determines the scaling of the time axis. (C) Exponential growth is consistent only with stable internal nitrogen concentration. Dose‐response curves expressed in reduced variables (the ratio between a variable and the same variable for a plant growing under optimal conditions) are universal, so that all species and all environmental conditions yield the same curve. This is confirmed by experimental data. The shape (linear, exponential, etc.) of the nitrogen uptake curve is the only parameter differentiating these universal curves. The Mitscherlich curve or variations of it can be fitted very closely to the derived dose‐response curves, except under exponential growth. A conclusion drawn from the analysis is that the results of nutrition experiments cannot be properly interpreted unless the variation with time of the amount of nitrogen in the plant is known. The theory can be extended to more complex situations, for example, time‐varying environmental con

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb01207.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

The intracellular distribution of serine hydroxymethyltransferase (EC 2.1.2.1) was studied in young wheat (Triticum aestivumL. cv. Starke II) leaves by fractionation of protoplasts and further purification of peroxisomes and chloroplasts. Essentially all of the activity in wheat leaves was located in the mitochondria. Within the mitochondria the enzyme was mainly in the matrix as shown by centrifugation of sonicated wheat mitochondria. In the C4plants,Zea mays(L. cv. Earliking),Panicum miliaceumandPanicum maximum(cv. Australia) belonging to different C4types, serine hydroxymethyltransferase was almost exclusively found in bundle sheath cells. The location of this enzyme in leaves is consistent with its role relative to glycine decarboxylation during photorespiration.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb01208.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

The optical properties of seed and fruit coats were examined from several varieties of light‐sensitive achenes.Taraxacum vulgareL. andLactuca sativaL. cv. Grand Rapids achenes with dark fruit coats andL. sativacvs Huvudsallat and Issallat with white fruit coats were examined. Transmission spectra varied among the different achenes: white fruit coats ofLactucaacted as neutral density filters between 450 and 780 nm, whereasTaraxacumtransmitted 2–36% in this region. The ribbed fruit coat structure greatly affected transmission so that at different locations in the same coat, transmission varied between 20 to 80% at 660 and 730 nm. Fruit coats of Grand Rapids lettuce andTaraxacumtransmitted more far‐red than red light with T660/T730ratios of 0.8 and 0.4, respectively. The relationship between the optical properties of fruit coats and light‐stimulated germination is di

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb01209.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Adventitious buds on embryos ofPicea abies(L.) Karst. developed after a pulse treatment with 250 μMbenzyladenine (BA) of pH 5.5 for 2 h. Light and temperature regimes were not critical during the initial stages. Adventitious buds developed faster after a pulse treatment and the variation among different experiments was lower compared to when the embryos were cultured on media supplemented with BA. Various stages of the differentiation of adventitious buds were identified: stage 1 ‐ appearance of meristematic centres (approximately the first two weeks); stage 2 ‐ development of adventitious bud primordia (approximately the third week); stage 3 ‐ adventitious bud development (from approximately the 4th to the 8th week). This system may be used for further studies on bud different

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb01210.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Pricking one cotyledon of decapitated plantlets ofBidens pilosus L.induces, i) the induction of a wave of electric depolarization progressing towards the bud at the axil of this cotyledon, and ii) the inhibition of the growth of this bud. The electrophysiologic and morphogenetic responses are dependent on the number of pricks and on the location of these pricks on the cotyledon midribs. When a prick is delivered on the hypocotyl prior to those on the cotyledons, then it prevents the effect of the latter pricks. When it is delivered after those on the cotyledons, it does not change the effects of cotyledon pricking. Our experiments suggest that there is a causal relationship between the electrophysiological and morphogenetic responses.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb01211.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Indole‐3‐butyric acid (IBA, 10−4M), spermine (7 × 10−5M) and vitamin D2(6.3 × 10−5M), all of which enhance rooting in mung bean cuttings (Phaseolus aureusRoxb. cv. Berkin), influence RNA metabolism. Total and poly (A)+‐RNA synthesis within the hypocotyl is inhibited by each of these chemicals within 24 h. These changes precede induced cell division and are therefore associated with the so‐called inductive period of regeneration during which some cells in the hypocotyl undergo dedifferentiation. However, following subsequent transfer of cuttings to borate, which is an essential prerequisite for development of root primordia in these cuttings, RNA synthesis is enhanced by pretreatments with IBA, spermine or vitamin D2. Furthermore, IBA inhibits synthesis and turnover of protein withi

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb01212.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

In the present report the suggestion (Paech, K. 1950. Biochemie und Physiologie der sekundären Pflanzenstoffe. ‐ Springer, Berlin, pp. 201–203) was tested that the photosynthetic apparatus requires light protection during the early phase of its development and that this is the reason (in a teleonomic sense) for the transient formation of large amounts of juvenile anthocyanin in outer tissue layers of seedlings and young leaves of deciduous trees and shrubs. Seedlings of two species (Sinapis albaL. andSesamum indicumL.) which differ in their potential to produce anthocyanin were compared under identical light conditions. The results obtained are compatible with the idea that juvenile anthocyanins are involved in photoprotection. However, the experimental results also indicate that full photostability of the plastid is attained ‐ irrespective of the presence or absence of anthocyanin ‐ once a certain amount of chlorophyll has been accumulated. Thus, photosensitivity of a seedling under natural light conditions is restricted to an early phase of development prior to intense

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb01213.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Mitotic activity and nuclear DNA synthesis in tomato (Lycopersicon esculentumMill., cv. King plus) flowers targeted for abortion under unfavorable light conditions are completely stopped 6 days after macroscopic appearance of the inflorescence. Ovular cells are arrested at the G1(80%) and G2(20%) stages of the cell cycle. Exogenous applications of a mixture of N6‐benzyladenine (BA) and gibberellins A4+7(GA) directly on the inflorescence may prevent its failure. Nuclear DNA synthesis and mitoses resume in ovules of the flower 16 to 20 h after the BA+GA treatment. When applied alone, BA and GA are able to mimic the effect of the mixture upon the progression of ovular cells through their cycle. Sporogenesis processes are also set in motion by the exogenous plant growth regulators. The mechanism of action of cytokinins and gibberellins in the control of floral development is discusse

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb01214.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY