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1.
Gametophores of mosses Mnium undulatum and Polytrichum commune were submerged in distilled water or in calcium chloride solution (0.9 mM Ca2+) to induce hypoxia. The net photosynthetic (PN) and dark respiration rate (RD) were measured in the air containing 300–400 μmol(CO2)·mol−1(air) and 0.21 mol(O2)·mol−1(air). PN of M. undulatum gametophores decreased to 58 % of the control after 1-h submersion in water, whereas to 80 % of the control in P. commune gametophores. A smaller decrease in PN was observed when the gametophores were immersed in CaCl2 solution. In hypoxia, RD in the tested mosses species was a little higher than in the control. 相似文献
2.
B. Mittra S. Sharma A. B. Das S. L. Henry T. K. Das P. Ghosh S. Ghosh P. Mohanty 《Biologia Plantarum》2008,52(2):343-346
A 51-kDa soluble protein was over-expressed in wheat (Triticum aestivum) seedlings by the treatment of seeds before germination with 50 μM CdCl2 for 48 h and subsequently washed off Cd2+. This protein designated as Cd stress associated protein (CSAP), was purified. Polyclonal antibody was raised against CSAP
for localizing the protein in root tissue of treated and control seedlings. It was observed that CSAP was located below the
plasma membrane and outer periphery of the tonoplast. This unique type of organized localization of CSAP is suggestive of
defensive role against metal phytotoxicity. N-terminal analysis of CSAP and expressed sequence tags (EST) database search
of wheat sequences suggests that this protein has not been reported earlier in higher plants. 相似文献
3.
X. Wei Y. S. Jiang S. Y. Jiang X. X. Qi Z. C. Xiong W. H. Ye Z. M. Wang 《Photosynthetica》2008,46(2):312-314
Saturation (SI) and compensation (CI) irradiances [μmol(photon) m−2 s−1] were 383.00±18.40 and 12.95±0.42 for wild C. nitidissima (in mid-July) and 691.00±47.39 and 21.91±1.28 for wild C. sinensis, respectively. C. nitidissima is a shade tolerant species, whereas C. sinensis has a wide ecological range of adaptability to irradiance. Both wild and cultivated C. nitidissima demonstrated low maximum net photosynthetic rate, maximum carboxylation rate, maximum electron transfer rate, and SI, which
indicated low photosynthesis ability of leaves that were unable to adapt to strong irradiance environment. Both C. nitidissima and C. sinensis demonstrated strong photosynthetic adaptabilty in new environments. Hence proper shading may raise photosynthetic efficiency
of cultivated C. nitidissima and promote its growth. 相似文献
4.
Rates of net photosynthesis (P
N) and transpiration (E), and leaf temperature (TL) of maintenance leaves of tea under plucking were affected by photosynthetic photon flux densities (PPFD) of 200–2 200 μmol
m−2 s−1. P
N gradually increased with the increase of PPFD from 200 to 1 200 μmol m−2 s−1 and thereafter sharply declined. Maximum P
N was 13.95 μmol m−2 s−1 at 1 200 μmol m−2 s−1 PPFD. There was no significant variation of P
N among PPFD at 1 400–1 800 μmol m−2 s−1. Significant drop of P
N occurred at 2 000 μmol m−2 s−1. PPFD at 2 200 μmol m−2 s−1 reduced photosynthesis to 6.92 μmol m−2 s−1. PPFD had a strong correlation with TL and E. Both TL and E linearly increased from 200 to 2 200 μmol m−2 s−1 PPFD. TL and E were highly correlated. The optimum TL for maximum P
N was 26.0 °C after which P
N declined significantly. E had a positive correlation with P
N. 相似文献
5.
A field experiment was conducted with two cassava cultivars and eight levels of nitrogen to examine the relationship between
extractable chlorophyll (Chl) content of cassava leaves and both the Chl meter value (SPAD) and leaf colour chart (LCC) score.
The SPAD, LCC, and Chl a+b content were influenced by leaf position, growth stage, cultivar (cv.), and N fertilization. The cvs. and N fertilization
had significant effect on SPAD, LCC, and Chl a+b content of youngest fully expanded leaf (leaf 1) blade in most cases. An F-test indicated that common equations pooled across
cvs., N fertilization, and growth stages could be used to describe the relationships between Chl a+b content and LCC and between SPAD and LCC, but not between SPAD and Chl a+b content. Relationships between tuber yield and SPAD, LCC, and Chl a+b content were significant (p<0.05) and positive at 30 and 60 d after planting. Thus LCC and SPAD can be used to estimate leaf Chl content which is an
indicator of leaf N status. 相似文献
6.
In order to study the responses of winter wheat cultivars released in different years to short-term high O3 exposure, an old cultivar (‘Nongda 311’, released in 1960s) and a modern one (‘Yannong 19’, released in 1990s) were treated
with an O3 exposure (145 ± 12 mm3 m−3, 4 h d−1 for 3 d) shortly after anthesis stage (> 50 % main stems blossomed). During the O3 exposure, light-saturated photosynthetic rate (P
N) and stomatal conductance (g
s) of both cultivars decreased considerably. Elevated O3 did not decrease dark-adapted maximum photochemical efficiency, but induced significant reduction in actual photochemical
efficiency and thereby considerably increase in non-photochemical quenching. P
N, g
s of the modern cultivar ‘Yannong 19’ decreased more than the older one ‘Nongda 311’, indicating the former exhibited higher
sensitivity to O3 than the latter. After O3 exposure, P
N, g
s and chlorophyll (Chl) content in flag leaf decreased more quickly than control, indicating induction of faster premature
leaf senescence. As a result, the short-term O3 exposure caused substantial yield loss, with larger reduction in ‘Yannong 19’ (−19.2 %) than in ‘Nongda 311’ (−8.4 %). Our
results indicated that high O3 exposure at grain filling stage would have greater negative impacts on the high yielding modern cultivar relative to the
old one with lower yield. 相似文献
7.
We investigated the carbon isotope ratios and the diurnal pattern of malate accumulation in leaves and aerial roots of eight
species of Phalaenopsis grown in greenhouses. The leaves of all the species showed carbon isotope ratios and the diurnal patterns of malate content
typical of CAM plants. However, the aerial roots exhibited a large variation in the diurnal pattern of malate content among
species and even among plants within the same species, although carbon isotope ratios were always CAM-like values. Some aerial
roots showed the typical diurnal pattern of CAM, but others maintained high or low malate contents during a day without fluctuation.
In order to characterize more strictly the nature of the malate variation in the aerial roots, we further investigated a possible
variation of the diurnal pattern of malate among different aerial roots within an individual for Phalaenopsis amabilis and P. cornu-cervi. The diurnal pattern of malate content was varied even among different aerial roots within the same plant. Thus the photosynthetic
carbon metabolism in aerial roots of orchids is fairly complex. 相似文献
8.
A method for determination of oxalate with oxalate oxidase (OxO, EC 1.2.3.4) prepared from wheat bran, is based on specific
oxidation of oxalate to produce H2O2. The H2O2 formed was colorimetrically determined using horseradish peroxidase-catalyzed oxidation of 4-aminoantipyrine and N,N-dimethylaniline
by H2O2. The new method was tested on rice, buckwheat, soybean and oxalis leaves, showing it is precise, sensitive, inexpensive,
highly reproducible and simple to perform. Good agreement could be obtained between this method and the HPLC. 相似文献
9.
Hydrated thalli of the lichen Lobaria pulmonaria were either preconditioned to dim irradiance (DI, 5 μmol m−2 s−1) or medium irradiance (MI, 200 μmol m−2 s−1) for 6 h. After this 6 h period, the thalli were allowed to desiccate under the two respective irradiances. Thereafter, these
dry lichens were exposed to high irradiance (HI, 1 000 μmol m−2 s−1) for 60 h. After this HI treatment, the maximal photochemical quantum yield (FV/FM) and the de-epoxidation state of xanthophyll cycle pigments (DEPS) were highest in thalli preconditioned to MI. Hence irradiance
in the last hydrated period before sampling is significant for the physiological state of lichens. A standardized irradiance
pre-treatment before start of experiments is recommended. 相似文献
10.
To examine the hypothesis that stomatal behavior of plants in dry soil is influenced by a slow recovery from daytime water
deficit, we studied the effect of repeated wetting of leaves during evening and night in Cryptomeria japonica seedlings grown in dry soil. After 7 and 10 days of leaf wetting treatment the midday leaf water potential decreased and
the transpiration rate increased, respectively. Therefore, we suggest that rapid recovery from daytime water deficit could
weaken the water conserving stomatal behavior that adapts to drought conditions in the roots. 相似文献
11.
Stress-induced degradation of D1 protein and its photoprotection by DCPIP in isolated thylakoid membranes of barley leaf 总被引:1,自引:0,他引:1
Effects of various stress treatments such as NaCl, hydrogen peroxide, hydroxyl free radical, and high irradiance (HI, 1 000
μmol m−2 s−1) on the photosystem (PS) 2 mediated electron transport rate and the degradation of D1 protein in the thylakoid membranes
of barley were studied. The applied stresses caused significant reduction in the PS 2-mediated electron transport and a degradation
of D1 protein that was highest during the HI-treatment. Presence of 2,6-dichlorophenol indophenol (DCPIP), which is an artificial
electron acceptor from water, significantly minimizes the HI-induced deleterious effect on the PS 2-mediated electron transport
rate, disarrangement of PS machinery, and degradation of the D1 protein. HI in the absence of an acceptor resulted in production
of reactive oxygen species due to electron transfer to oxygen. 相似文献
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15.
The chlorophyll fluorescence (F) temperature curves in a linear time-temperature heating/cooling regime were used to study
heat-induced irreversible F changes in primary green leaves of spring barley (Hordeum vulgare L. cv. Akcent). The leaf segments were heated in a stirred water bath at heating rates of 0.0083, 0.0166, 0.0333, and 0.0500
°C s−1 from room temperature up to maximal temperature T
m and then linearly cooled to 35 °C at the same rate. The F intensity was measured by a pulse-modulated technique. The results
support the existence of the two critical temperatures of irreversible F changes postulated earlier, at 45–48 and 53–55 °C.
The critical temperatures are slightly dependent on the heating rate. Two types of parameters were used to characterize the
irreversibility of the F changes: the coefficient of irreversibility μ defined as the ratio of F intensity at 35 °C at the
starting/ending parts of the cycle and the slopes of tangents of linear parts of the F temperature curve. The dependence of
μ on T
m revealed a maximum, which moved from 54 to 61 °C with the increasing heating/cooling rate v from 0.0083 to 0.0500 °C s−1, showing two basic phases of the irreversible changes. The Arrhenius and Eyring approaches were applied to calculate the
activation energies of the initial increase in μ. The values varied between 30 and 50 kJ mol−1 and decreased slightly with the increasing heating rate. 相似文献
16.
One of the least understood enzymatic steps in chlorophyll biosynthesis is the formation of isocyclic ring, which is catalyzed
by the Mg-protoporphyrin IX monomethyl ester (MgPME) cyclase that is involved in the conversion of MgPME to protochlorophyllide.
Several genes encoding part of this enzyme have been identified and functional analysis of them has been performed. The enzyme
plays important roles in higher plants and photosynthetic bacteria. The review focuses on the current knowledge of MgPME cyclase
coding genes, with emphasis on their organization, expression pattern, and functional analysis obtained from mutants. 相似文献
17.
We have investigated the effects of cadmium on the microtubular (MT) cytoskeleton in the root tip cells of Allium sativum L. using indirect immunofluorescence microscopy. Cd affected the mechanisms controlling the organization of MT cytoskeleton,
as well as tubulin assembly/disassembly processes. Cd induced the formation of abnormal MT arrays, consisting of discontinuous
wavy MTs or short MT fragments at the cell periphery. Cadmium caused irregular nuclear disorder in cells where the MT organization
and function was disturbed. Furthermore, with increased Cd concentration and duration of treatment the MTs depolymerized more
severely, the frequency of abnormal cell increased and the mitotic index decreased progressively. The above findings showed
that MT cytoskeleton is one of target sites of Cd toxicity in root tip cells. 相似文献
18.
A. I. Cordeiro J. F. Sanchez-Sevilla M. C. Alvarez-Tinaut M. C. Gomez-Jimenez 《Biologia Plantarum》2008,52(4):642-647
Eighty seven olive (Olea europaea ssp. sativa L.) cultivar accessions from Portugal were characterized by means of randomly amplified polymorphic DNA (RAPD) markers. Of
the 11 arbitrary 10-mer primers tested a total of 92 polymorphic bands were obtained, representing 87.6 % of the total amplification
products. Twenty nine different genotypes were clearly discriminated. Differences were not found among the amplification profiles
from different individuals of the same cultivar. All the genotypes could be identified by the combination of three primers:
OPR-1, OPK-14 and OPA-1, seven genotype-specific markers being detected. Genetic relationships were estimated by the unweighted
pair-group method with arithmetic averaging (UPGMA). The genetic analysis of the results showed a gradual distance between
the various cultivars, making it difficult to identify well-differentiated phylogenetic groups, although two clusters were
distinguishable with 35 % similarity, in addition to three independent branches with lower similarity: Galega, Tentilheira
and Redondal. The dendrogram reflect some relationships for most of the cultivars according to the use of the fruit and ecological
adaptation. 相似文献
19.
G.-Y. Kai L.-M. Dai X.-Y. Mei J.-G. Zheng W. Wang Y. Lu Z.-Y. Qian G.-Y. Zhou 《Biologia Plantarum》2008,52(3):557-560
An efficient in vitro plant regeneration system from leaves of Ophiorrhiza japonica Blume was established for the first time. Callus formation rate was more than 90.4 % from leaf segments on Murashige and
Skoog (MS) supplemented with either α-naphthaleneacetic acid (NAA) alone or in combination with 6-benzyladenine (BA). The
highest shoot regeneration (78.9 %) was achieved on MS medium containing 2.0 mg dm−3 BA and 0.2 mg dm−3 NAA, with an average of 9.4 shoots developed per leaf segment. Shoot regeneration was also improved when the leaf explants
were cultured in MS basal medium supplemented with 0.5 % (m/v) polyvinylpyrrolidone (PVP). The leaf explants from seedlings
with age of about 18–27 d showed the highest shoot regeneration. The regenerated shoots were rooted on half-strength basal
MS medium supplemented with 0.5 mg dm−3 indole-3-butyric acid (IBA), which averagely produced 24.8 roots per shoot. The plantlets were transferred to soil, where
100 % survived after 1 month of acclimatization. 相似文献
20.