ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1992.tb01306.x

年代:1992

数据来源: WILEY

摘要:

SUMMARYThe common opinion that cellulose microfibril deposition in cell walls of meristematic cells is random will have to be revised. In tunica, corpus and rib meristem cells ofPetunia hybridaandVinca majormicrofibrils are deposited in parallel arrays. The cell walls of corpus cells consist of lamellae. Each lamella has a different microfibril orientation. As a consequence, the random distribution of cortical microtubules found in corpus cells (Sakaguchiet al.1988) bear no direct relation to the parallel deposition of cellulose microfibrils in the walls of these cells.

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1992.tb01307.x

年代:1992

数据来源: WILEY

摘要:

SUMMARYThe development and (ultra‐)structure of mucilage cells in the shoot apex and leaf inHibiscus schizopetalus(Mast.) Hook.f. is described. In the shoot apex, mucilage cells mostly develop simultaneously in pairs. The mucilage was initially deposited as a layer between the plasma membrane and the cell wall. After prolonged mucilage deposition, the remaining cytoplasm was located in the centre of the cell, where it degenerated. At maturity, several mucilage cells arranged in one line, showed local breakdown of their common cell walls, and thus formed a canal or cavity which was surrounded by a sheath of smaller neighbouring cells. In the mesophyll, mucilage cells were present underneath the veins. The development was similar to that of mucilage cells in the shoot apex. Finally, several mucilage cells were aligned parallel to the vein and, after local cell‐wall breakdown, fused with each other forming a kind of canal. Mucilage cells in the adaxial epidermis deposited mucilage against the inner, peripheral cell‐wall. Upon prolonged mucilage deposition, the cytoplasm remained at the outer peripheral wall of the cells. In none of the mucilage cells ofHibiscus schizopetaluswas a suberized layer detected in the cell wall. The differences between mucilage cells of the Malvaceae and those of the Lauraceae and Annonaceae are disc

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1992.tb01308.x

年代:1992

数据来源: WILEY

摘要:

SUMMARYSynthesis of chloroplast proteins associated with induced leaf senescence in barley (Hordeum vulgareL., var. Hassan) was studied. Leaf segments were incubated for 18–27 h in the dark, floating on distilled water (senescence induction) or on kinetin (senescence retardation). Radioactivity was readily incorporated into plastid protein (followed after different incubation times of leaf segments with [14C] labelled amino acids) and increased during the first 3 h of incubation. Radioactive plastid polypeptides were analysed by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate and fluorography. Several polypeptides (48, 38, 28, 23 and 20 kDa), were synthesized very actively when leaf segments were incubated in the dark, but synthesis was low or absent in greening leaves or when senescence was retarded by kinetin. The results confirm that synthesis of some senescence‐specific chloroplast polypeptides is impaired by kinetin treatm

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1992.tb01309.x

年代:1992

数据来源: WILEY

摘要:

SUMMARYThe effect of drought stress on the growth of nine accessions of lentil, ILL 5845, ILL 6451, ILL 6788, ILL 6793, ILL 6796, ILL 6439, ILL 6778, Local Masoor and Masoor 18–10 was assessed in a pot experiment, using control and drought cycles.Accessions ILL 6439 and ILL 6451 produced significantly greater biomass, had highest osmotic adjustment, a high wax content, a high leaf resistance, a high relative water‐content and high leaf elasticity (Δψw/ΔR = gradient of water potential/gradient of relative water content) compared with the other accessions.From this study, it is established that the drought tolerance of the lentil accessions examined here is highly related to their capacity for osmotic adjustment. Thus osmotic adjustment could be a selection criterion for breeding for drought resistance in lentil. The detection of variation in the response to drought stress in a very small sample of lentil accessions examined here suggests that the advancement of drought tolerance through selection and breeding methods is po

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1992.tb01310.x

年代:1992

数据来源: WILEY

摘要:

SUMMARYUnivariate and multivariate analyses of 28 morphological traits were carried out on seven tetraploid and 16 diploid accessions ofLathyrus pratensisL. grown under uniform conditions. More than 80% of the plants from diploid populations but less than 50% from the tetraploids flowered the first growing season. Cluster analysis (Wards' method) and principal component analysis did not provide clear differences between these cytotypes. Discriminant function analysis based on ploidy level identified those characters which can provide a reasonably good separation. The results confirmed thatL. pratensiscan still be regarded as a semi‐cryptic species with two cytological races in which tetraploids have arisen through autopolyploid

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1992.tb01311.x

年代:1992

数据来源: WILEY

摘要:

SUMMARYHistorical biogeographic analyses of abstract examples obtained by the parsimonious technique Component Compatability (CC) are interpreted. Subjects such as Brooks' Parsimony Analysis (BPA), vicariance, dispersal, extinction, primitive absence, non‐reaction to speciation events, coding techniques, missing areas, interdependence between contemporary species and ancestral species, hybrid areas, outgroup areas, and peripheral areas are treated. Distributions are explained in principle as vicariance events; homoplasies givead‐hocexplanations such as dispersal, extinction, etc. Methods still need to be improved as several problems in the interpretation of areagrams are due to their inadequac

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1992.tb01312.x

年代:1992

数据来源: WILEY

摘要:

SUMMARYParameters such as crown architecture and biomass were combined with data on gas exchange, nutrient concentrations and biochemical changes to investigate the influence of air pollution in two Douglas fir stands (Garderen and Kootwijk). Most branch parts were found in the middle level on third‐order branches: in Garderen there were twice as many as in Kootwijk and therefore there were twice as many needles. Current‐year needles in the middle canopy accounted for 40% of the total number of needles. Under certain environmental conditions ozone was found to reduce photosynthetic production by 7–25%. The most significant changes in nutrients were found in the concentrations of K and Ca in the current year's ne

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1992.tb01313.x

年代:1992

数据来源: WILEY

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1992.tb01314.x

年代:1992

数据来源: WILEY

摘要:

Evolutionary Biology of the Marine Algae of the North AtlanticD.J. Garbary and G.R. South (eds). Springer‐Verlag, Berlin. 1990. x + 429 pp. Illustrated, hardback, DM198.00. ISBN 3–540–51

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1992.tb01317.x

年代:1992

数据来源: WILEY