摘要:

ABSTRACTThis review attempts to give a concise overview of the widespread occurrence and the significance, structure and function of pheromones in the chemical communication between individuals of the same species during sexual reproduction in algae and plants. Also included is information on the Oomyctes and the chytridiomyceteAllomyces.The terminology in respect of pheromone function and pheromone‐induced reactions is discusse

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1993.tb00513.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACTSprings emitting carbon dioxide are frequent in Central Italy and provide a way of testing the response of plants to CO2enrichment under natural conditions. Results of a CO2enrichment experiment on soybean at a CO2spring (Solfatara) are presented. The experimental site is characterized by significant anomalies in atmospheric CO2concentration produced by a large number of vents emitting almost pure CO2(93%) plus small amounts of hydrogen sulphide, methane, nitrogen and oxygen. Within the gas vent area, plants were grown at three sub‐areas whose mean CO2concentrations during daytime were 350,652 and 2370 μmol mol‐1, respectively. Weekly harvests were made to measure biomass growth, leaf area and ontogenetic development. Biomass growth rate and seed yield were enhanced by elevated CO2. In particular, onto‐morphogenetic development was affected by elevated CO2with high levels of CO2increasing the total number of main stem leaf nodes and the area of the main stem trifoliolate leaves. Biochemical analysis of plant tissue suggested that there was no effect of the small amounts of H2S on the response to CO2enrichment. Non‐protein sulphydryl compounds did not accumulate in leaf tissues and the overall capacity of leaf extracts to oxidize exogenously added NADH was not decreased. The limitations and advantages of experimenting with crop plants at elevated CO2in the open and in the proximity of carbon dioxide springs are d

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1993.tb00514.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACTGomphrena macrocephalaSt.‐Hil. (Amaranthaceae) is a perennial herb that grows spontaneously in thecerradoand is characterized by well‐defined phenological phases throughout the year. Soluble carbohydrates are the main reserve compounds of the tuberous root and constitute approximately 50% of the dry weight. These sugars were partially characterized as fructans forming a single homologous series, different from inulin, the most common fructan of dicotyledons. The mean molecular weight of polysaccharides was high and reached 37 kDa in the dormant phase. Fructan spherocrystals were detected in the tuberous root after treatment with ethanol, being associated with the parenchyma of secondary xylem. The content, composition and mean molecular weight of fructans were related to phenology. In late dormancy, there was a marked increase in monosaccharides, particularly fructose, and a concomitant decline of polysaccharides, probably as a result of fructan breakdown. During sprouting and in the vegetative phase, the contents of oligosaccharides and low molecular weight polysaccharides increased. A gradual rise in the molecular weight of polysaccharides occurred during the reproductive phase and at early dormancy, concurrently with decreasing levels of oligosaccharides. The capacity ofG. macrocephalato accumulate readily accessible sugars, such as fructans, instead of starch, in response to environmental changes, may be of considerable advantage, since thecerradois often subjected to seasonal drought and burni

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1993.tb00515.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACTPhotomorphogenic mutants of tomato were used to probe the possible involvement of phytochrome A in photosynthetic acclimation to shade. Plants of wild‐typeLycopersicon esculentum, the near isogenic mutantsaurea(au, deficient in phytochrome A, and also possibly other phytochromes) andhigh pigment(hp, exhibiting exaggerated photomorphogenic responses), and theau/hpdouble mutant were grown in a greenhouse under either unfiltered daylight, or daylight attenuated by neutral density filters or green filters that simulated the spectral effects of vegetation shade. Growth and photosynthetic parameters were measured over a growing period of 15 d. Typical effects of simulated vegetation shade on extension growth were observed only in the wild‐type andhpstrains; the presence of theaulesion resulted in reduced capacity to respond to vegetation shade by increased extension. Photosynthetic light saturation curves obtained using infrared gas analysis at 15 d indicated that neither theaunor thehpmutations caused serious reductions in maximum net photosynthetic rate in plants acclimated to full daylight, although theau/hpdouble mutant showed a significantly reduced maximum rate. In the wild‐type andhpstrains grown under both neutral and simulated vegetation shade, the photosynthetic light saturation curves were similar. Plants with theaulesion showed a significantly lower capacity to acclimate to vegetation shade, as seen by their reduced maximum rate of net photosynthesis. However,in situmeasurements of photosynthetic rate in the greenhouse were indistinguishable between the four strains. Thylakoid stoichiometry measurements revealed a very large increase in PSII/PSI ratio under simulated vegetation shade as compared with either unfiltered daylight or neutral density shade. These increases were not diminished in the phytochrome‐deficientaustrains, and were even larger in thehpstrains. The results indicate that theaulesion has little effect on the capacity of tomato to exhibit photoadaptation to simulated vegetational shade when measured at the thylakoid level. On the other hand, net leaf photosynthesis under vegetation shade can be significantly affected by the phytochrome deficiency caused by theaumutation, implying a possible role for one or more of the phytochromes in photoadaptation at the lea

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1993.tb00516.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACTEnvironmental influences on carbon isotope fractionation in tree rings require further elucidation in order to use this parameter as a biological marker of climatic variations. δ13C values in tree‐ring cellulose of beech (Fagus sylvaticaL.) were analysed for the period from 1950 to 1990. A bioclimatic model of water balance was used to give the actual evapotranspiration as well as the soil water content on a daily basis. δ13C shows a significant decrease from –24·5‰ to –25‰ over this period. Internal CO2concentration changes from 200 to 220 ppm in relation with the rise of atmospheric CO2. Beside a slight non‐significant inter‐individual variation, a large year‐to‐year variation exists. The relative extractable soil water of July, combined with the value of δ13C for the previous year, predicts as much as 70% of this variance. Air temperature or precipitation accounted for less variation. δ13C is strongly correlated with basal area increment, but appeared a more reliable indicator of water sta

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1993.tb00517.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACTA rhizotron was used to study fine‐root demography in mature vines of kiwifruit (Actinidia deliciosa). The vines were grown in a deep, well drained, silt loam and received normal orchard management. Roots were measured from 10 to 160cm depth at biweekly intervals for 2 years. After an initial phase of rapid colonisation of the repacked soil behind the rhizotron windows, the total length of visible roots per vine remained quite steady. This apparent stability of the total belied fast and sustained localized turnover of the fine roots at all soil depths. Fifty‐one per cent of the roots survived ≤28d, 69% died at an age ≤56d and only 8% survived>252d. For each year, the cumulative length of roots grown was equivalent to about 2·75 times the maximum net length of roots visible. These may be the largest annual rates of root turnover yet reported. This has important ramifications for the carbon balance, mineral nutrition and water relations of t

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1993.tb00518.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACTThestl1andstl2mutations confer low and high levels of NaCl tolerance to gametophytes of the fernCeratopteris richardii, respectively. As an initial characterization of these mutations, the levels of various organic solutes, tissue ion content and water relations were examined in the wild‐type and mutant strains in the absence and presence of 60 mol m‐3NaCl stress (a level which results in a 20, 15 and 0% reduction in gametophyte growth in the wild‐type,stl1mutant andstl2mutant, respectively). All strains exhibited major changes in organic and inorganic solute levels and water relations in response to 60 mol m‐3NaCl stress. Differences in organic solute levels and water relations between the wild‐type and mutant strains in the absence and in response to 60 mol m‐3NaCl stress were minimal. Analysis of tissue ion content showed thatstl1was associated with a slight reduction in Na+accumulation during 60 mol m‐3NaCl stress.stl2was associated with (1) higher constitutive levels of K+and (2) continued selective accumulation of K+and reduced accumulation of Na+during 60 mol m‐3NaCl stress. A K+/Na+ratio close to 1 was observed in the wild‐type during 60 mol m‐3NaCl stress, while higher ratios were detected instl1andstl2(1·7 and 4·0, respectively). The findings of this study suggest that the tolerance imparted bystl1andstl2is associated with altered ion accumulation during NaCl stress, rather than an enhanced ability to accumulate organic solutes to be used for osmotic adjust

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1993.tb00519.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACTColloidal gold‐labelled antibody was used to localize indole‐3‐acetic acid in caps of primary roots ofZ. mayscv. Kys. Gold particles accumulated on the nucleus, vacuoles, mitochondria, and some dictyosomes and dictyosome‐derived vesicles. This is the first localization of indole‐3‐acetic acid in dictyosomes and dictyosome‐derived vesicles and indicates that dictyosomes and vesicles constitute a pathway for indole‐3‐acetic acid movement in and secretion from root cap cells. Our findings provide cytochemical evidence to support the hypothesis that indole‐3‐acetic acid plays an important role

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1993.tb00520.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACTThe effects of long‐term water stress on water and terpene contents of the foliage ofCupressus sempervirenswere studied. A great deal of water was lost over 2 months before a remarkable stabilization. A strong decrease of all the classes of terpenes accompanied this dehydration. Mono‐ and sesquiterpene hydrocarbons and free terpenols were almost entirely metabolized, whereas esters and terpene glycosides rose slightly and remained at a constant level when the water content had stabilized. Although a significant part of the mono‐ and sesquiterpene hydrocarbons was emitted in the early stage of stress application, the major part was used by the plant in response to the drought condi

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1993.tb00521.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACTIn at least18plant families, leaves or flowers can maintain a specific orientation with respect to diurnal movements of the sun. Previous work on heliotropic leaves has demonstrated that blue light (400–500nm) provides the cue for their tracking response. Floral heliotropism occurs in several families of arctic and alpine plants, but the spectral sensitivity of the response has not been studied previously. Moreover, no studies on the spectral sensitivity of any heliotropism have been conducted on wild plants growing in their natural habitat. Working under field conditions, we used coloured acrylic filters to determine whether heliotropism by flowers of the snow buttercup (Ranunculus adoneus) is responsive to broad‐band blue or red light. Flowers were able to orient towards the sun under boxes made entirely of blue‐transmitting filters and in red‐transmitting boxes having a single blue side that faced the sun. In these treatments, solar tracking ability was not significantly different from that observed in adjacent control flowers. In contrast, the precision of solar orientation was significantly reduced in red‐transmitting boxes and red boxes with a single blue side oriented away from the sun. In the early morning, flowers covered by red‐transmitting boxes failed to orient in the direction of sunrise, suggesting that this floral response, unlike that seen in some heliotropic leaves, lacks a residual‘memory’ for previous

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1993.tb00522.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY