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1.
C. Alström-Rapaport M. Lascoux U. Gullberg 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(3-4):493-497
Various ecological factors (e.g. herbivory, difference between males and females in colonising ability) have been invoked
to explain female-biased sex ratios in populations of willow species. It was implicitly assumed that genetic factors would
lead to a balanced sex ratio in the absence of ecological disturbances. In an experiment carried out in a homogeneous environment
and in the absence of herbivores the progeny sex ratio of 13 crosses of basket willow (Salix viminalis L.) was observed to range from extreme female bias to extreme male bias. The observed sex ratio cannot be explained by the
presence of sex chromosomes without assuming that additional loci are also involved in the sex determination. Alternatively,
the sex ratios in this study can be explained by a sex determination mechanism governed by multiple independent loci.
Received: 1 February 1996 / Accepted: 14 June 1996 相似文献
2.
Characterisation of the differential interference effects of two boreal dwarf shrub species 总被引:4,自引:0,他引:4
Our purpose was to characterize the relative competitive and phytotoxic potential of two closely related dwarf-shrub species, Empetrum nigrum and E. hermaphroditum, which form clones in a mosaic pattern in post-fire successions of the boreal forest of northern Sweden. We determined morphological
and growth parameters of both species, performed bioassays and chemical analysis, and established field experiments to explore
possible differing interference effects on trees by the two species. Both Empetrum species had very similar morphological and growth characteristics. E. hermaphroditum exerted considerably greater negative effects than E. nigrum against Pinus sylvestris and Populus tremula seed and seedlings. These negative effects were related to the different substitution of a bibenzyl in the two species. The
effect on seed germination of the two bibenzyls isolated from E. nigrum and E. hermaphroditum was compared with that of other simple phenolics; the latter were found to be inactive, indicating a specific phytotoxic
component in the bibenzyls. P. sylvestris seeds planted into clones of both species in the field revealed that E. hermaphroditum had much stronger inhibitory effects than did E. nigrum and the addition of activated carbon partially reversed these effects. Seed germination, biomass and survival of P. sylvestris after four seasons were significantly lower in E. hermaphroditum- than in E. nigrum-dominated plots. We conclude that while both Empetrum species are superficially very similar morphologically, they have vastly different effects on tree seed germination, seedling
establishment and growth. These effects appear to be due, at least in part, to the different chemical profile of the two species.
Received: 2 April 1999 / Accepted: 2 November 1999 相似文献
3.
Stephen H. Bullock 《International journal of biometeorology》1997,41(1):13-16
Seasonal drought may limit primary productivity in most of the tropics, but the determinants of tree growth are not well
known. A 10-year study of the deciduous trees Cochlospermum vitifolium (Willd.) Spreng. (Cochlospermaceae) and Cnidoscolus spinosus Lundell (Euphorbiaceae) in southwestern México showed radial growth to be highly correlated (both r>0.85) only with precipitation during an interval of <2 months in the mid-wet season. Growth was not affected by total annual
precipitation or by an early starting or late ending of the wet season, or by heavy rainfall in the dry season. Annual mean
girth increments ranged from 0.03 to 3.31 cm and −0.1 to 2.01 cm, respectively. The best model for growth (r
2>0.85) was a linear combination of mid-summer precipitation (positive coefficient) and total precipitation over the previous
2 years (negative coefficient). Comparison with other species showed heterogeneous responses of wood production to climate
variation, and suggests that the range of functional types of dry forest trees is still unknown.
Received: 9 September 1996 / Accepted: 4 March 1997 相似文献
4.
Dew and its effect on two heliophile understorey species of a tropical dry deciduous forest in Mexico 总被引:1,自引:0,他引:1
Víctor L. Barradas M. Guadalupe Glez-Medellín 《International journal of biometeorology》1999,43(1):1-7
A series of horizontal and vertical measurements of dew deposition and dew duration were carried out in a tropical dry deciduous
forest in western Mexico (19° 30′ N, 105° 03′ W). The effect of dew on transpiration in heliophile species was also investigated.
The amount of dew was very variable with no temporal or spatial pattern. The amount of dew measured at two horizontal transects
(maximum and minimum) (at heights of 0.20 m and 1.30 m above ground level) was from 0.014 to 0.203 mm and from 0.013 to 0.061 mm
in the middle and at the end of the dry season, respectively. Dew deposition at different vertical levels (0.50–12.5 m height)
ranged from 0.04 to 0.36 mm. The duration of dew formation ranged between 60 and 129 min after sunrise above the canopy (a
height of 11 m), and between 259 and 290 min after sunrise at a height of 2 m. Daily transpiration rates were 883 and 632 g
m–2 d–1 in Coccoloba liebmannii and 538 and 864 g m–2 d–1 in Jacquinia pungens in January and April, respectively. Transpiration was restricted from sunrise to early afternoon in April, as a result of
the pronounced midday closure of stomata in both species. The reduction of transpiration by dew ranged from 13.2 to 50.1 g
m–2 d–1 and from 4.5 to 77.7 g m–2 d–1 for C. liebmannii and J. pungens, respectively. Dew can play an important role in enhancing the survival of heliophile species in the dry season by reducing
transpiration rates during the morning.
Received: 30 April 1998 / Accepted: 14 December 1998 相似文献
5.
D. Spano Carla Cesaraccio Pierpaolo Duce Richard L. Snyder 《International journal of biometeorology》1999,42(3):124-133
The objectives of this paper are to: (1) present 10 years of phenological data for nine natural species growing in a Mediterranean-type
climate, (2) present threshold temperatures that were derived for the computation of cumulative degree-days (CDD), and (3)
evaluate the sensitivity of the nine natural species to weather variability. The study was conducted at the Phenological Research
Garden of Oristano, Sardinia, Italy, during the period 1986–96. The observations were made on five typical Mediterranean species
and four species that are typical of higher latitudes. The mean annual pattern of phenological events and the CDD from 1 January
are given for each development stage. Temperature thresholds were evaluated by comparing the standard deviation about the
mean number of days in the development period for each species. A good relationship between timing of phenophase occurrence
and temperature was observed for the Mediterranean species, which were little affected by variations in rainfall. Phenological
development of the non-native species was affected by springtime rainfall.
Accepted: 28 October 1998 相似文献
6.
Many plant species exhibit inflorescence morphologies intermediate between pollination syndromes and may therefore employ
generalist pollination strategies. We studied how wind and insect pollination are related to inflorescence morphology in the
floodplain species Salix alba, S. elaeagnos, S. daphnoides and S. triandra. Insect exclusion experiments showed that all four species were primarily pollinated by insects, but were capable of some
seed set when wind was the only pollen vector. Such a generalist pollination system may provide reproductive assurance in
these pioneer species. High wind pollination success was associated with slender and divided stigmatic lobes and low ovule
number per catkin, which may enhance filtering capacity for airborne pollen. In contrast, species that relied more on insect
pollination had robust stigmata and many ovules per catkin, which may reduce the number of insect visits necessary for pollination.
Received April 18, 2002; accepted July 23, 2002 Published online: November 28, 2002
Addresses of authors: S. Karrenberg (e-mail: karrenberg@bio.indiana.edu), Department of Biology, Indiana University, Jordan
Hall, 1001 East Third Street, Bloomington, IN 47405, USA. P. J. Edwards, Geobotanical Institute, ETH, Zürichbergstrasse 38,
CH-8044 Zürich, Switzerland. J. Kollmann, Department of Ecology, Royal Veterinary and Agricultural University, Rolighedsvej
21, DK-1958 Frederiksberg, Denmark. 相似文献
7.
Tor Myking 《Trees - Structure and Function》1997,12(2):107-112
Effects of fluctuating and constant temperatures on budburst time, and respiration in winter buds were studied in Betula pubescens Ehrh. Dormant seedlings were chilled at 0°C for 4 months and then allowed to sprout in long days (LD, 24 h) at constant temperatures
of 6, 9, 12, 15, 18 and 21°C, and at diurnally fluctuating temperatures (12/12 h, LD 24 h) with means of 9, 12, 15 and 18°C.
No difference in thermal time requirements for budburst was found between plants receiving constant and fluctuating temperatures.
The base temperature for thermal time accumulation was estimated to 1°C. Respiration in post-dormant (dormancy fully released)
excised winter buds from an adult tree increased exponentially with temperature and was 20 times as high at 30°C than at 0°C.
However, respiration in buds without scales was 30% higher at 0°C, and it was 2.7 times higher at 24°C than in intact buds.
Thus, the tight bud scales probably constrain respiration and growth and are likely to delay budburst in spring. Arrhenius
plots of the respiration data were biphasic with breaks at 13–15°C. However, this phase transition is unlikely to be associated
with chilling sensitivity since the present species is hardy and adapted to a boreal climate.
Received: 10 January 1997 / Accepted: 23 June 1997 相似文献
8.
The research was designed to characterize the phenological behaviour of different apple varieties and to compare different
bioclimatic indexes in order to evaluate their adaptability in describing the phenological phases of fruit species. A field
study on the requirement for chilling units (winter chilling requirement) and the accumulation of growing degree hours of
15 native apple cultivars was carried out in a fruit-growing area in North West Italy (Cuneo Province, Piedmont). From 1991
to 1993, climatic data were collected at meteorological stations installed in an experimental orchard (Verzuolo, Cuneo). Four
methods were compared to determine the winter chilling requirement: Hutchins, Weinberger-Eggert, Utah and North Carolina.
The Utah method was applied to determine the time when the chilling units accumulated become effective in meeting the rest
requirements. A comparison of the different methods indicated that the Weinberger-Eggert method is the best: as it showed
the lowest statistical variability during the 3 years of observations. The growing degree hour requirement (GDH) was estimated
by the North Carolina method with two different base temperatures: 4.4°C and 6.1°C. More difficulties were met when the date
of rest completion and the beginning of GDH accumulation was determined. The best base temperature for the estimation of GDH
is 4.4°C. Phenological and climatic characterizations are two basic tools for giving farmers and agricultural advisors important
information about which varieties to choose and which are the best and the most correct cultivation practices to follow.
Received: 25 October 2000 / Revised: 6 August 2001 / Accepted: 6 August 2001 相似文献
9.
Mapping of quantitative trait loci controlling adaptive traits in coastal Douglas-fir. I. Timing of vegetative bud flush 总被引:1,自引:0,他引:1
K. D. Jermstad D. L. Bassoni K. S. Jech N. C. Wheeler D. B. Neale 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,102(8):1142-1151
Thirty three unique quantitative trait loci (QTLs) affecting the timing of spring bud flush have been identified in an intraspecific
mapping population of coastal Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco var. menziesii]. Both terminal and lateral bud flush were measured over a 4-year period on clonal replicates at two test sites, allowing
for the repeated estimation of QTLs. QTLs were detected on 12 linkage groups and, in general, each explained a small proportion
of the total phenotypic variance and were additive in effect. Several QTLs influence the timing of bud flush over multiple
years, supporting earlier evidence that the timing of bud flush through developmental stages is under moderate to strong genetic
control by the same suite of genes through developmental stages. However, only a few QTLs controlling the timing of bud flush
were detected at both test sites, suggesting that geographic location plays a major role in the phenology of spring growth.
A small number of QTLs with year and site interactions were also estimated.
Received: 20 July 2000 / Accepted: 19 October 2000 相似文献
10.
The mechanical properties of young stems of Aristolochia macrophylla Lam. and Aristolochia brasiliensis Mart. et Zucc. were studied during elongation growth and primary differentiation. Data for the modulus of elasticity, for
the viscoelastic behaviour caused by longitudinal tension and for the shear modulus resulting from torsion around a longitudinal
axis were related to the underlying structural changes by quantitative analysis of stem anatomy, tissue distribution, ultrastructure,
and cell wall biochemistry. The orientation of cellulose microfibrils was determined by light microscopy and small-angle X-ray
diffraction, and the lignin content was determined by thioglycolic acid derivatization and spectroscopic quantification. It
was demonstrated that the increase in stability during early development is due to the complementary effects of increase in
cell wall material, lignification, and cellulose microfibril alignment. A detailed micromechanical model, considering internal
prestresses, is proposed to explain the characteristic biphasic stress-strain behaviour as well as the strain-hardening observed.
Received: 22 March 1999 / Accepted 9 September 1999 相似文献
11.
Axillary bud banks of two semiarid perennial grasses: occurrence, longevity, and contribution to population persistence 总被引:4,自引:0,他引:4
The occurrence, longevity, and contribution of axillary bud banks to population maintenance were investigated in a late-seral
perennial grass, Bouteloua curtipendula, and a mid-seral perennial grass, Hilaria belangeri, in a semiarid oak-juniper savanna. Axillary buds of both species were evaluated over a 2-year period in communities with
contrasting histories of grazing by domestic herbivores. A double staining procedure utilizing triphenyl tetrazolium chloride
and Evan's blue indicated that both viable and dormant axillary buds remained attached to the base of reproductive parental
tillers for 18–24 months which exceeded parental tiller longevity by approximately 12 months. Bud longevity of the late-seral
species, B. curtipendula, exceeded bud longevity of the mid-seral species, H. belangeri, by approximately 6 months. Younger buds located on the distal portion of the tiller base were 3.2 and 1.4 times more likely
to grow out than older proximal buds of B. curtipendula and H. belangeri, respectively. The percentage of older proximal buds, which included comparable portions of viable and dormant buds, that
grew out to produce tillers following mortality of parental tillers was 6.0% for B. curtipendula and 8.4% for H. belangeri. In spite of the occurrence of relative large axillary bud banks for both species, the magnitude of proximal bud growth did
not appear sufficient to maintain viable tiller populations. We found no evidence to support the hypothesis of compensatory
bud growth on an individual tiller basis for either species. Grazing history of the communities from which the buds were collected
did not substantially affect the number, status, longevity, or outgrowth of axillary buds on an individual tiller basis for
either species. However, long-term grazing by domestic herbivores influenced axillary bud availability by modifying population
structure of these two species. Bud number per square meter for B. curtipendula was 25% lower in the long-term grazed compared to the long-term ungrazed community based on a reduction in both tiller number
per plant and plant number per square meter. In contrast, bud number per square meter for H. belangeri was 190% greater in the long-term grazed than in the long-term ungrazed community based on a large increase in plant density
per square meter. Minimal contributions of axillary bud banks to annual maintenance of tiller populations in this mid- and
late-seral species underscores the ecological importance of consistent tiller recruitment from recently developed axillary
buds. Consistent tiller recruitment in grasslands and savannas characterized by intensive grazing and periodic drought implies
that (1) bud differentiation and maturation must be remarkably tolerant of adverse environmental conditions and/or (2) tiller
recruitment may resume from buds that mature following the cessation of severe drought and/or grazing, rather than from mature
buds that survive these disturbances. These scenarios warrant additional research emphasis given the critical importance of
this demographic process to tiller replacement in species populations and the maintenance of relative species abundance in
grasslands and savannas.
Received: 12 August 1996 / Accepted: 30 December 1996 相似文献
12.
Stomatal versus biochemical limitations to dynamic photosynthetic performance in four tropical rainforest shrub species 总被引:6,自引:0,他引:6
Photosynthetic performance under dynamic light regimes was assessed in four different species of tropical shrubs from the
family Rubiaceae via field gas exchange measurements conducted on Barro Colorado Island, Panamá. Rates of photosynthetic induction
and induction loss were assessed throughout the day in both the wet and dry seasons in order to determine the relative roles
of stomata and biochemistry in limiting photosynthetic performance under transient light conditions. A high degree of coordination
was observed between stomatal conductance and biochemical capacity for CO2 assimilation during induction. Rates of biochemical and overall photosynthetic induction sharply decreased when initial stomatal
conductance fell below a narrow range of critical values. Time of day or season did not affect rates of biochemical deactivation
upon shading, but did influence stomatal closure, which often exerted a significant influence over induction loss in the darkness.
In measurements of total assimilation due to a 60-s light pulse, both biochemical activity and stomatal conductance were linearly
related to total CO2 uptake. Only during the mornings of the wet season was stomatal conductance consistently high enough to be non-limiting to
dynamic photosynthetic performance. At all other times, stomatal behavior exercised significant influence over induction times,
photosynthetic induction loss, and total CO2 uptake from 60-s light pulses.
Received: 17 March 1999 / Accepted: 26 October 1999 相似文献
13.
Dactylella leptospora and Dactylaria candida, and Arthrobotrys dactyloides (Hyphomycetes), capture nematodes by nonconstricting- and constricting-ring traps, respectively. In the formation of the
constricting-ring trap of the latter fungus, the basal portion of a curved hyphal branch put forth a bud to fuse with its
advancing tip to make a ring. However, in nonconstricting-ring formation in the former two fungi, the portion behind the tip
of the curved branch did not develop such a bud before fusion with the tip.
Received: May 31, 2002 / Accepted: July 5, 2002
Correspondence to:M. Saikawa 相似文献
14.
A cDNA fragment encoding a Lupinus albus. L. class-III chitinase, IF3, was isolated, using a cDNA probe from Cucumis sativus L., by in-situ plaque hybridization from a cDNA library constructed in the Uni-ZAP XR vector, with mRNAs isolated from mature
lupin leaves. The cDNA had a coding sequence of 293 amino acids including a 27-residue N-terminal signal peptide. A class-III
chitinase gene was detected by Southern analysis in the L. albus genome. Western blotting experiments showed that the IF3 protein was constitutively present during seed development and in
all the studied vegetative lupin organs (i.e., roots, hypocotyls and leaves) at two growth stages (7- and 20-d-old plants).
Accumulation of both the IF3 mRNA and IF3 protein was triggered by salicylic acid treatment as well as by abiotic (UV-C light
and wounding) and biotic stress conditions (Colletotrichum gloeosporioides infection). In necrotic leaves, IF3 chitinase mRNA was present at a higher level than that of another mRNA encoding a pathogenesis-related
(PR) protein from L. albus (a PR-10) and that of the rRNAs. We suggest that one role of the IF3 chitinase could be in the defense of the plant against
fungal infection, though our results do not exclude other functions for this protein.
Received: 15 March 1999 / Accepted: 12 July 1999 相似文献
15.
F. A. Aravanopoulos 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,100(8):1203-1208
The relations between heterozygosity derived from a total of 12 variable isoenzyme loci and total above-ground leafless biomass
production were examined in four full-sib families of Salix exigua, a willow species important in breeding efforts for short-rotation intensive-culture plantations. Relations were investigated
by comparing the performance of heterozygotes with that of corresponding homozygotes in locus by locus comparisons, by investigating
multiple regression models with individual loci as independent variables, and by employing the adaptive distance model. All
these analytical approaches resulted in the manifestation of the absence of any relations between isoenzyme loci and biomass
production. Possible reasons that may account for these results are discussed.
Received: 8 October 1999 / Accepted: 4 November 1999 相似文献
16.
17.
Applications of the growth promotive gibberellins (GAs) GA4 and 2,2-dimethyl GA4, and of C-16,17 endo-dihydro GA5, which is known to promote flowering while inhibiting stem growth in the long-day grass Lolium temulentum, were made to micropropagated plants of Metrosideros collina cv. Tahiti, a highly ornamental cultivar with an intermittent flowering pattern. Gibberellin A4 and 2,2-dimethyl GA4 stimulated vegetative growth both in elongating shoots, and internodes of shoots developing from buds that were quiescent at the time of GA application. Abscission of the apices of expanding shoots, a feature of mature Metrosideros plants, was inhibited by these GAs, the rejuvenation of micropropagated plantlets being enhanced. However, C-16,17 endo-dihydro GA5 differed from GA4 and 2,2-dimethyl GA4 by having no promotive effects on vegetative growth, and no inhibition of apical abscission. Notwithstanding this contrasting effect on vegetative growth, high doses of GA4 or C-16,17 endo-dihydro GA5 similarly reduced flowering on shoots to which either GA was applied. Reduced flowering in response to applied GAs is common in many woody angiosperms, and in this instance was probably the combined result of abortion of developing floral structures in quiescent buds, and a preferential inhibition of bud break for floral buds relative to vegetative buds, particularly by GA4. Finally, both C-16,17 endo-dihydro GA5 and GA4 strongly inhibited bud break in this woody angiosperm, although GA4 could initially stimulate bud break when applied to vegetative buds close to the expansion stage. The above findings, in toto, highlight the sensitivity of Metrosideros to both classes of GA in a variety of growth and development processes. 相似文献
18.
Temperature-dependent internode elongation in vegetative plants of Arabidopsis thaliana lacking phytochrome B and cryptochrome 1 总被引:1,自引:0,他引:1
Vegetative plants of Arabidopsis thaliana (L.) Heynh. form a compact rosette of leaves in which internode growth is virtually arrested. Rapid extension of the internodes
occurs after flower buds are present in the reproductive apex. Under natural radiation, continuous light from fluorescent
lamps, or short photoperiods of light from fluorescent lamps, plants of the phyB cry1 double mutant (lacking both phytochrome B and cryptochrome 1) did not form normal rosettes because all the internodes showed
some degree of elongation. Internode elongation was weak in the phyB single mutant and absent in the cry1 mutant, indicating redundancy between phytochrome B and cryptochrome 1. The absence of phytochrome A caused no effects. The
failure to form normal rosettes was conditional because internode elongation was arrested at low temperatures in all the mutant
combinations. In contrast, the temperature dependence of phytochrome B and cryptochrome 1 effects on hypocotyl growth was
weak. The elongation of the internodes in phyB cry1 was not accompanied by early flowering as showed by the lack of effects on the final number of leaves. Apex dissection indicated
that in phyB cry1 double mutants internode elongation anticipated the transition from the vegetative to the reproductive stage. Thus, stem
growth in Arabidopsis thaliana is not fully dependent on the program of reproductive development.
Received: 2 June 1999 / Accepted: 13 August 1999 相似文献
19.
Robert N. Magai W. L. Decker Armon J. Keaster 《International journal of biometeorology》1997,40(3):128-134
The European corn borer is one of the most damaging insect pests to maize in the United States. Different methods exist for
the estimation of time of damage to corn by first generation European corn borer. The most commonly used method is the linear
thermal constant concept of phenology which by convention calculates cumulative thermal units from January 1 or another arbitrary
date. Linear and nonlinear models based on the thermal units concept developed were to predict and simulate postdiapause development
of the European corn borer and subsequent infestation of the maize crop using early spring temperatures (May 1–15) in central
Missouri. The developmental rates of European corn borer were obtained from growth chamber investigations that simulated those
temperatures, the operational temperatures being selected from a compilation of archival meteorological data from 1948 to
1989. The linear and polynomial regression models were developed to predict phenological stages of the European corn borer
using thermal units as developmental rates. The models were compared against each other to determine the better predictor
of estimation values: each explained 94 and 98% of the variation in developmental stages, respectively. In addition, the models
were tested against independent field data and both models gave good predictions of developmental stages, indicating that
either model would be a good predictor.
Received: 9 September 1994 / Revised: 28 December 1995 / Accepted: 8 August 1996 相似文献