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1.
《中国科学:生命科学英文版》2010,(6)
In order to reveal the drought resistance and adaptation of the C4 desert plant Haloxylon ammodendron under artificially controlled soil moisture regimes,representative plants were selected to measure canopy photosynthesis using canopy photosynthetic measurement system.The results showed that appropriate soil moisture significantly enhances the canopy and leaf photosynthetic capacity,and extremely high soil moisture is not conducive to the photosynthesis of H.ammodendron. 相似文献
2.
Acacia ampliceps Maslin and Eucalyptus camaldulensis Dehnh. were grown for one year in lysimeters at three soil moisture regimes: 100 % (well-watered), 75 % (medium-watered) and 50 % (low-watered) of total plant available water. Biomass yield of both species increased with increase in soil moisture. Water-use efficiency (WUE) of E. camaldulensis decreased and that of A. ampliceps increased markedly with decrease in available soil moisture. A. ampliceps showed 4 – 5 times more biomass yield than E. camaldulensis grown at similar soil moisture. A. ampliceps showed almost 5, 9 and 12 times higher WUE than E. camaldulensis under low-, medium- and well-watered treatments, respectively. Significant negative correlation of 13C with WUE (r = –0.99) was observed in A. ampliceps. In contrast, 13C of E. camaldulensis showed a significant positive correlation with WUE (r = 0.82). 相似文献
3.
Diurnal variations in net photosynthetic rate (P
N), transpiration rate (E), stomatal conductance (g
s), internal CO2 concentration (C
i), and water use efficiency (WUE) were studied on individual leaves of coffee plants to determine the effect of climatic factors
on photosynthetic capacity. P
N and E showed bimodal behaviour with the maximum values of P
N at mid-morning. At noon, under saturating photosynthetically active radiation (PAR) and high leaf temperature (T
l), P
N declined. In the afternoon (14:00), P
N slightly recovered in association with a decrease in Tl and in leaf-to-air vapour pressure deficit (VPD). Reductions in E during the morning were associated with decreases in g
s. Higher WUE in the morning was related to higher P
N and lower E. The reverse occurred in the afternoon. Goudriaan's simulation model, adapted for coffee canopy photosynthesis, was tested
at the level of whole plant (P
pl). Three methods were used: (a) Whole plant net photosynthesis (P
pl) under semi-controlled conditions in a chamber. (b) P
pl estimation following Goudriaan's method (Gaussian integration) of instantaneous P
N in single leaves at three canopy depths and at three different hours assuming a photosynthesis unimodal behaviour. (c) P
pl using Goudriaan's method but at five different hours according to the bimodal behaviour reported above. Results of P
pl estimates using Goudriaan's model adapted for coffee canopy confirm the observed P
pl bimodal behaviour with high fitness degree of the measured whole plant photosynthesis. The high fitness found among observed
and simulated data indicates that the modified model may be used as a subroutine for the general simulation model of coffee
crop growth. 相似文献
4.
Mehdi Ladjal Nathalie Deloche Roland Huc Michel Ducrey 《Trees - Structure and Function》2007,21(2):201-213
Three- and four-year-old potted, greenhouse-grown cedar seedlings were subjected to two different watering regimes: half received
full water supply and the other half was submitted to moderate drought (50% of the full water supply). Height growth was the
greatest for C. atlantica and the most-limited for C. brevifolia in the well-watered set. However, in the dry set, height growth was less affected by drought conditions for C. brevifolia than for C. atlantica. Cedrus libani gave intermediate results for both watering regimes. Moderate drought provoked a decrease in osmotic potential at full leaf
turgor and a long-lasting osmotic adjustment. When irrigation was withheld completely to induce severe soil drying, gas exchange
decreased and then stopped at predawn water potentials of −3.0 MPa for C. brevifolia, between −2.6 and −2.8 MPa for C. libani, and at −2.4 MPa for C. atlantica, irrespective of watering regime. For all species, the dry set showed lower net photosynthesis (A) and stomatal conductance (g
s) than the plants in the well-watered set. A and g
s responded to variations in atmospheric water-vapour pressure deficit (VPD). As VPD increased, A and g
s decreased, and this trend was proportionate to initial values at low VPD, but remained independent of previous watering treatments,
plant water status or species. To conclude, C. brevifolia appears to be a species with limited growth potential but strong soil drought tolerance whereas C. atlantica has strong growth potential when an adequate water supply is available but is more sensitive to soil drought. C. libani shows an intermediate behaviour for growth and drought tolerance. 相似文献
5.
Summary A method has been developed for the induction of adventitious shoots from leaf tissue of Echinacea pallida with subsequent whole-plant regeneration. Proliferating callus and shoot cultures were derived from leaf tissue explants
placed on Murashige and Skoog medium supplemented with 6-benzylaminopurine and naphthaleneacetic acid combinations. The optimum
shoot regeneration frequency (63%) and number of shoots per explant (2.3 shoots per explant) was achieved using media supplemented
with 26.6 μM 6-benzylaminopurine and 0.11 μM naphthaleneacetic acid. Rooting of regenerated shoot explants was successful on Murashige and Skoog medium, both with and
without the addition of indole-3-butyric acid. All plantlets survived acclimatization, producing phenotypically normal plants
in the greenhouse. This study demonstrates that leaf tissue of E. pallida is competent for adventitious shoot regeneration and establishes a useful method for the micropropagation of this important
medicinal plant. 相似文献
6.
The objective of this study was to assess genotypic variation in soybean chlorophyll (Chl) content and composition, and to
test if these data could be used as a rapid screening method to predict genotypic variation in leaf tissue N content. Chl
contents and composition were examined among 833 soybean (Glycine max L. Merr.) accessions and related to SPAD meter readings and leaf N content. In the initial year of the study (2002), the
relationship between leaf Chl and leaf N contents (r
2 = 0.043) was not sufficiently close for Chl to be useful as a predictive tool for leaf N content. Therefore, leaf N content
was not determined in 2004 but samples were again collected for determination of Chl content and composition. In 2002, the
soybean accessions separated into two distinct groups according to leaf Chl a/b ratios, with the majority of a mean ratio of 3.79. However, approximately 7 % (60) of the genotypes could be readily assigned
to a group with a mean Chl a/b ratio of 2.67. Chl a/b analyses in 2004 confirmed the results obtained in 2002 and of 202 genotypes, all but 6 fell into the same group as in 2002. 相似文献
7.
Two repeated DNA sequences isolated from a partial genomic DNA library of Helianthus annuus, p HaS13 and p HaS211, were shown to represent portions of the int gene of a Ty3 /gypsy retroelement and of the RNase-Hgene of a Ty1 /copia retroelement, respectively. Southern blotting patterns obtained by hybridizing the two probes to BglII- or DraI-digested genomic DNA from different Helianthus species showed p HaS13 and p HaS211 were parts of dispersed repeats at least 8 and 7 kb in length, respectively, that were conserved in all species studied. Comparable hybridization patterns were obtained in all species with p HaS13. By contrast, the patterns obtained by hybridizing p HaS211 clearly differentiated annual species from perennials. The frequencies of p HaS13- and p HaS211-related sequences in different species were 4.3x10(4)-1.3x10(5) copies and 9.9x10(2)-8.1x10(3) copies per picogram of DNA, respectively. The frequency of p HaS13-related sequences varied widely within annual species, while no significant difference was observed among perennial species. Conversely, the frequency variation of p HaS211-related sequences was as large within annual species as within perennials. Sequences of both families were found to be dispersed along the length of all chromosomes in all species studied. However, Ty3 /gypsy-like sequences were localized preferentially at the centromeric regions, whereas Ty1/ copia-like sequences were less represented or absent around the centromeres and plentiful at the chromosome ends. These findings suggest that the two sequence families played a role in Helianthusgenome evolution and species divergence, evolved independently in the same genomic backgrounds and in annual or perennial species, and acquired different possible functions in the host genomes. 相似文献
8.
To determine what factors limit the growth of wild Fritillaria cirrhosa and Fritillaria delavayi in field conditions, we investigated diurnal changes of the net photosynthetic rate (P
N) and the correlation between P
N and various environmental factors. Parameters of chlorophyll (Chl) fluorescence were evaluated to test whether ecological
fragility caused the extinction of wild F. cirrhosa and F. delavayi. Our study reveals for the first time that F. cirrhosa and F. delavayi did not encounter significant stress under field conditions. A small reduction in maximum photochemical efficiency was observed
under high irradiance. The maximum P
N of F. cirrhosa was 30 % higher than F. delavayi (p<0.05), and a similar difference was observed for apparent quantum yield (27.3 %, p<0.01). F. delavayi was better adapted to a wide range of irradiances and high environmental temperature. Correlation between P
N and environmental factors (without considering the effects of interactions among environmental factors on P
N) using leaves of F. cirrhosa revealed that the three primary influencing factors were air pressure (p<0.01), relative humidity (p<0.01), and soil temperature (p<0.05). In F. delavayi, the influencing factors were relative humidity (p<0.01), soil temperature (p<0.05), CO2 concentration (p<0.05), and air pressure (p<0.05). Path analysis (considering effects among environmental factors on P
N) showed that air temperature (negative correlation), photosynthetic photon flux density (PPFD) and relative humidity were
the three primary limiting factors influencing the growth of F. cirrhosa. For this species, relative humidity reacted indirectly with air pressure, which was reported singularly in other species.
Limiting growth factors for F. delavayi were PPFD, air pressure (negative correlation), soil temperature (negative correlation) and air temperature (negative correlation). 相似文献
9.
This study describes two phenotypes of Arabidopsis thaliana (ecotype Columbia) developed in vitro under salt stress (75 mM NaCl). The phenotypes 01 and 02 appeared visibly distinguishable by rosette morphology and competence
to produce flowers. Phenotype 01, sensible to salt stress, accumulated high quantities of Na+, showed a slight reduction in dry mass, and high protein and chlorophyll contents. Moreover, its anatomy exhibited some xeromorphic
traits. Phenotype 02, clearly salt tolerant, showed a morphology similar to control plants, displaying typical phyllotactic
rosette and flowering stalk production. Accumulation of Na+, protein and chlorophyll contents were close to control plants. Reversion experiments on NaCl free MS medium, showed a partially
recovered phenotype 01. A threshold salt stress concentration that permits the simultaneous development of two phenotypes,
was found. 相似文献
10.
The responses to precipitation of Haloxylon ammodendron (C.A. Mey.) Bunge (Chenopodiaceae), a small xerophilous tree growing on contrasting textured soils, were evaluated under
no, natural, and double precipitation treatments during the entire growing season of 2006. The contrasting textured soils
are sandy and heavy textured, and both are the original habitat of H. ammodendron at the south edge of Gubantonggute Desert, Central Asia. Photosynthesis, leaf water potential, transpiration, water use efficiency
and leaf biomass production were monitored throughout the growing season. Root distribution of H. ammodendron was evaluated at the end of the experiment. Overall, this small tree did not show significant response to a large summer
precipitation pulse or precipitation treatments, in terms of photosynthetic carbon assimilation on either soil. The leaf water
potential, transpiration, and water use efficiency appeared to be highly sensitive to a large precipitation pulse and precipitation
treatments in sandy soil; and leaf biomass production was also much higher for plants in sandy than that of heavy-textured
soil. In sandy soil, defoliation occurred when pre-dawn leaf water potential dropped below −3.0 MPa, while in heavy-textured
soil, defoliation occurred when pre-dawn leaf water potential dropped below −3.75 MPa. For similar above-ground parts, the
small trees at the sandy site developed much deeper root systems and had nearly double the surface area of feeder roots compared
to those at the heavy-textured site. Partially owning to the deeper and larger root system, H. ammodendron growing at coarse-textured site was in better water conditions than those at heavy-textured site under the same climatic
conditions. 相似文献
11.
Noel H. Holmgren 《Brittonia》2018,70(1):115-139
A revision of Penstemon sect. Saccanthera subsect. Serrulati includes a new species (P. salmonensis), a new variety (P. triphyllus var. infernalis), and the elevation of a subspecies to species (P. curtiflorus), bringing the total number of species to eight, which are keyed and described, complete with nomenclature and type citations. 相似文献
12.
A genetic transformation system has been developed for callus cells of Crataegus
aronia using Agrobacterium
tumefaciens. Callus culture was established from internodal stem segments incubated on Murashige and Skoog (MS) medium supplemented with
5 mg l−1 Indole-3-butyric acid (IBA) and 0.5 mg l−1 6-benzyladenine (BA). In order to optimize the callus culture system with respect to callus growth and coloration, different
types and concentrations of plant growth regulators were tested. Results indicated that the best average fresh weight of red
colored callus was obtained on MS medium supplemented with 2 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.5 mg l−1 kinetin (Kin) (callus maintenance medium). Callus cells were co-cultivated with Agrobacterium harboring the binary plasmid pCAMBIA1302 carrying the mgfp5 and hygromycin phosphotransferase (hptII) genes conferring green fluorescent protein (GFP) activity and hygromycin resistance, respectively. Putative transgenic calli
were obtained 4 weeks after incubation of the co-cultivated explants onto maintenance medium supplemented with 50 mg l−1 hygromycin. Molecular analysis confirmed the integration of the transgenes in transformed callus. To our knowledge, this
is the first time to report an Agrobacterium-mediated transformation system in Crataegus
aronia. 相似文献
13.
Mazurkiewicz-Zapałowicz Kinga Wróbel Jacek Janowicz Krystyna 《Acta Physiologiae Plantarum》2004,26(2):157-164
The influence of saprotrophic soil fungi: Aspergillus versicolor, Penicillium frequentans, Penicillium verrucosum var. cyclopium, and Trichocladium asperum on development, wholesomeness, gas exchange and yield of potato cv. Mila was studied in pot experiments during 1998–2000.
The presence of each of the mentioned fungi species in soil accelerated potato germination and stimulated growth of overground
plant parts in comparison with control plants. Additionally, the presence of the tested saprotrophes in soil prologed the
potato growing period by inhibiting chloroses of necroses. The tested saprotrophic fungi also modified plant physiological
processes, such as transpiration and assimilation. The contact of plant root system with soil saprotrophes diminished significantly
assimilation and transpiration intensity of overground parts in comparison with the control plants, in all the years of the
experiment. However, this response did not reduce the yield of tubers. 相似文献
14.
Studying Pneumocystis has proven to be a challenge from the perspective of propagating a significant amount of the pathogen in a facile manner.
The study of several fungal pathogens has been aided by the use of invertebrate model hosts. Our efforts to infect the invertebrate
larvae Galleria
mellonella with Pneumocystis proved futile since P. murina neither caused disease nor was able to proliferate within G. mellonella. It did, however, show that the pathogen could be rapidly cleared from the host. 相似文献
15.
The maT clade of transposons is a group of transposable elements intermediate in sequence and predicted protein structure to mariner and Tc transposons, with a distribution thus far limited to a few invertebrate species. We present evidence, based on searches of publicly available databases, that the nematode Caenorhabditis briggsae has several maT-like transposons, which we have designated as CbmaT elements, dispersed throughout its genome. We also describe two additional transposon sequences that probably share their evolutionary history with the CbmaT transposons. One resembles a fold back variant of a CbmaT element, with long (380-bp) inverted terminal repeats (ITRs) that show a high degree (71%) of identity to CbmaT1. The other, which shares only the 26-bp ITR sequences with one of the CbmaT variants, is present in eight nearly identical copies, but does not have a transposase gene and may therefore be cross mobilised by a CbmaT transposase. Using PCR-based mobility assays, we show that CbmaT1 transposons are capable of excising from the C. briggsae genome. CbmaT1 excised approximately 500 times less frequently than Tcb1 in the reference strain AF16, but both CbmaT1 and Tcb1 excised at extremely high frequencies in the HK105 strain. The HK105 strain also exhibited a high frequency of spontaneous induction of unc-22 mutants, suggesting that it may be a mutator strain of C. briggsae. 相似文献
16.
Alexandre Alonso Alves Lúcio Mauro da Silva Guimarães Agnaldo Rodrigues de Melo Chaves Fábio Murilo DaMatta Acelino Couto Alfenas 《Acta Physiologiae Plantarum》2011,33(5):1831-1839
One of the most important diseases of eucalyptus plantations is caused by the rust fungus Puccinia psidii. While the genetic basis of rust resistance has been addressed recently, little is known about the physiological aspects
of Eucalyptus–P. psidii interaction. In order to fill this gap, we undertook a study investigating the effects of P. psidii infection on photosynthetic processes of two E. urophylla clones with contrasting resistance to the pathogen. Our results show that gas exchange and chlorophyll a fluorescence parameters were virtually unaffected in the resistant clone. In the susceptible clone, photosynthetic rates
were chiefly constrained by biochemical limitations to carbon fixation. Photosynthesis was impaired only in symptomatic tissues
since the reductions in photosynthetic rates were proportional to the diseased leaf area. Rust infection provoked chronic
photoinhibition to photosynthesis in the susceptible clone. Overall, differences in the ability for light capture, use and
dissipation may play a significant role in explaining the clonal differences in Eucalyptus in response to P. psidii infection. To our knowledge, this is the first report of the effect of rust infection on gas exchange and chlorophyll a fluorescence parameters in Eucalyptus. 相似文献
17.
K. P. Martin A. Shahanaz Beegum C.-L. Zhang A. Slater P. V. Madhusoodanan 《Biologia Plantarum》2007,51(4):769-772
In vitro propagation of an anticancerous drug synthesizing plant, Ophiorrhiza prostrata D. Don, was established through indirect somatic embryogenesis. Friable embryogenic calluses were initiated from O. prostrata leaf and internode explants on Murashige and Skoog (MS) media supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D) either
alone or in combination with N6-benzyladenine (BA) or kinetin (KIN). Somatic embryos were developed after subculture of the friable calluses onto half strength
MS media containing 0.45 or 2.26 μM 2,4-D alone or in combination with BA or KIN. Medium supplemented with 2.26 μM 2,4-D and
2.22 μM BA was optimal, supporting the production of a mean of 5.8 globular embryos. Subculture of globular embryo-bearing
calluses on half strength MS medium without growth regulators produced the highest embryo frequency, and the majority of them
developing to early torpedo stage. Somatic embryos underwent maturation and converted to plantlets at high frequency (90 %)
on half strength MS medium supplemented with 0.44 μM BA. Somatic embryo-derived plantlets with well-developed roots were established
in field conditions with a 90 % survival rate. 相似文献
18.
Summary Camptothecin, produced by Camptotheca acuminata, is a pharmaceutically important compound. Transgenic technology has potential uses for the enhancement of camptothecin production;
however, an efficient plant regeneration protocol for C. acuminata is not currently available. Factors that affected successful seedling germination were evaluated. The regeneration potential
of various parts of seedlings was tested. Camptothecin production in regenerated plants was compared to its production in
calluses and the original seedlings. Dark incubation and seed coat removal led to a higher germination rate and a higher survival
rate after germination. The best shoot induction medium was found to be Gamborg's B5 medium+8.9 μM benzyladenine. Among the calluses induced from various parts of seedlings, leaf petiole calluses, leaf dise calluses, and
cotyledon calluses regenerated shoots, but internode calluses did not. Furthermore, leaf petiole calluses and leaf dise calluses
regenerated normal shoots, while cotyledon calluses regenerated hyperhydric shoots. Moreover, leaf petiole calluses had a
higher shoot regeneration rate, 50% versus 9%, and a higher shoot number, 6.2±0.5 versus 2.0±0.3, than did leaf dise calluses
on the best shoot induction medium. It took 4–6 wk to regenerate shoots after transfer into shoot induction media. Camptothecin
concentration in the regenerated plants was significantly higher than that in the calluses and similar to that in the original
seedlings. In conclusion, leaf petioles provide efficient plant regeneration of C. acuminata. 相似文献
19.
This paper describes multiple shoot regeneration from leaf and nodal segments of a medicinally important herb Centella asiatica L. on Murashige and Skoog’s (MS) medium supplemented with a range of growth regulators. The highest number of multiple shoots
was observed on MS augmented with 3.0 mg dm−3 N6-benzylaminopurine (BAP) and 0.05 mg dm−3 α-naphthaleneacetic acid (NAA). Leaf explant showed maximum percentage of cultures regenerating shoots (81.6 %), with the
highest shoot number (8.3 shoots per explant) and the shoot length (2.1 cm) whereas, nodal explant showed less number of shoots
with callus formation at the base cut end. Successive shoot cultures were established by repeatedly sub-culturing the original
explant on a fresh medium. Rooting of in vitro raised shoots was best induced on half strength MS supplemented with 0.5 mg dm−3 indole-3-butyric acid (IBA) with highest percentage of shoot regenerating roots (76.8 %) with 3–4 roots per shoot. Plantlets
were acclimated in Vermi-compost and eventually established in soil. Contents of chlorophyll, total sugars, reducing sugars and proteins were estimated in
leaf tissue from both in vivo and in vitro raised plants. Chlorophyll content was higher in in vivo plants, whereas other three components were higher in in vitro plants. 相似文献
20.
Plantlets of coconut were cultured in vitro under three different ambient conditions including a standard culture room, a culture room inside a glasshouse with natural light but controlled temperature, and a standard glasshouse with natural light and natural fluctuations of temperature. Plantlets from the 3 treatments were compared in terms of growth, plant survival as well as net photosynthesis and efficiency of PSII (Fv/Fm ratio) both at the end of the in vitro stage and at 3 stages of ex vitro acclimatization. At the end of the in vitro stage, plantlets cultured in vitro under glasshouse conditions showed the best performance showing the highest photosynthesis rate, dry weight and number of leaves. Plantlets from the standard culture room showed the lowest photosynthesis and growth rate. After 6 months of ex vitro acclimatization, plantlets originally grown in vitro under glasshouse conditions maintained better field survival and growth rates in terms of fresh weight, dry weight and leaf number than plantlets originally grown in vitro in the standard culture room. Although more studies are required to define the reason for this effect, it is clear that the conditions of standard culture rooms are not the best for in vitro cultivation of coconut and perhaps other tropical species. 相似文献