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1.
Tomato (C3-plants) and maize (C4-plants) were grown in a nutrient solution to which triacontanol was added twice a week. After about 4 weeks the triacontanol treatment caused a significant increase in the dry weight of the tomato plants. Leaf area and dry weight measurements of tomato leaves at different stages of development showed that the largest increase in growth was obtained when triacontanol treatment was initiated before bud formation. In maize, no effect of the triacontanol treatment on dry wieght was observed. Photosynthesis was inhibited by 27% in young leaves from triacontanol-treated tomato plants and 39% in the controls, when the oxygen concentration was raised from 2% to 21%. In maize no change in photosynthesis could be observed, neither after altered oxygen concentration nor after triacontanol treatment. The difference in the response of C3- and C4-plants to triacontanol indicates that it regulates processes related to photosynthesis. 相似文献
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3.
Pyankov VI Voznesenskaya EV Kuz'min AN Ku MS Ganko E Franceschi VR Black CC Edwards GE 《Photosynthesis research》2000,63(1):69-84
Most species of the genus Salsola (Chenopodiaceae) that have been examined exhibit C4 photosynthesis in leaves. Four Salsola species from Central Asia were investigated in this study to determine the structural and functional relationships in photosynthesis of cotyledons compared to leaves, using anatomical (Kranz versus non-Kranz anatomy, chloroplast ultrastructure) and biochemical (activities of photosynthetic enzymes of the C3 and C4 pathways, 14C labeling of primary photosynthesis products and 13C/12C carbon isotope fractionation) criteria. The species included S. paulsenii from section Salsola, S. richteri from section Coccosalsola, S. laricina from section Caroxylon, and S. gemmascens from section Malpigipila. The results show that all four species have a C4 type of photosynthesis in leaves with a Salsoloid type Kranz anatomy, whereas both C3 and C4 types of photosynthesis were found in cotyledons. S. paulsenii and S. richteri have NADP- (NADP-ME) C4 type biochemistry with Salsoloid Kranz anatomy in both leaves and cotyledons. In S. laricina, both cotyledons and leaves have NAD-malic enzyme (NAD-ME) C4 type photosynthesis; however, while the leaves have Salsoloid type Kranz anatomy, cotyledons have Atriplicoid type Kranz anatomy. In S. gemmascens, cotyledons exhibit C3 type photosynthesis, while leaves perform NAD-ME type photosynthesis. Since the four species studied belong to different Salsola sections, this suggests that differences in photosynthetic types of leaves and cotyledons may be used as a basis or studies of the origin and evolution of C4 photosynthesis in the family Chenopodiaceae.This revised version was published online in October 2005 with corrections to the Cover Date. 相似文献
4.
Ammonium and nitrate as different forms of nitrogen nutrients impact differently on some physiological and biochemical processes in higher plants. Compared to nitrate, ammonium results in small root and small leaf area, which may contribute to a low carbon gain, and an inhibition on growth. On the other hand, due to (photo)energy saving, a higher CO (2) assimilation rate per leaf area was observed frequently in plants supplied with ammonium than in those supplied with nitrate. These results were dependent not only on higher Rubisco content and/or activity, but also on RuBP regeneration rate. The difference in morphology such as chloroplast volume and specific leaf weight might be the reason why the CO (2) concentration in the carboxylation site and hence the photorespiration rate differs in plants supplied with the two nitrogen forms. The effect of nitrogen form on water uptake and transportation in plants is dependent both on leaf area or shoot parameter, and on the root activity (i.e., root hydraulic conductivity, aquaporin activity). 相似文献
5.
Species in the Laxa and Grandia groups of the genus Panicum are adapted to low, wet areas of tropical and subtropical America. Panicum milioides is a species with C3 photosynthesis and low apparent photorespiration and has been classified as a C3/C4 intermediate. Other species in the Laxa group are C3 with normal photorespiration. Panicum prionitis is a C4 species in the Grandia group. Since P. milioides has some leaf characteristics intermediate to C3 and C4 species, its photosynthetic response to irradiance and temperature was compared to the closely related C3 species, P. laxum and P. boliviense and to P. prionitis. The response of apparent photosynthesis to irradiance and temperature was similar to that of P. laxum and P. boliviense, with saturation at a photosynthetic photo flux density of about 1 mmol m-2 s-1 at 30°C and temperature optimum near 30°C. In contrast, P. prionitis showed no light saturation up to 2 mmol m-2 s-1 and an optimum temperature near 40°C. P. milioides exhibited low CO2 loss into CO2-free air in the light and this loss was nearly insensitive to temperature. Loss of CO2 in the light in the C3 species, P. laxum and P. boliviense, was several-fold higher than in P. milioides and increased 2- to 5-fold with increases in temperature from 10 to 40°C. The level of dark respiration and its response to temperature were similar in all four Panicum species examined. It is concluded that the low apparent photorespiration in P. milioides does not influence its response of apparent photosynthesis to irradiance and temperature in comparison to closely related C3 Panicum species.Abbreviations AP
apparent photosynthesis
- I
CO2 compensation point
- gl
leaf conductance; gm, mesophyll conductance
- PPFD
photosynthetic photon flux density
- PR
apparent photorespiration rate
- RuBPC
sibulose bisphosphate carboxylase 相似文献
6.
Summary A procedure for the regeneration of fertile transgenic white mustard (Sinapis alba L.) is presented. The protocol is based on infection of stem explants of 7–9 day old plants with an Agrobacterium tumefaciens strain harboring a disarmed binary vector with chimeric genes encoding neomycin phosphotransferase and -glucuronidase. Shoots are regenerated from callus-forming explants within 3–4 weeks. Under selection, 10% of the explants with transgenic embryonic callus develop into fertile transgenic plants. Rooting shoots transferred to soil yield seeds within 14–16 weeks following transformation. Integration and expression of the T-DNA encoded marker genes was confirmed by histochemical glucuronidase assays and Southern-DNA hybridization using primary transformants and S1-progeny. The analysis showed stable integration and Mendelian inheritance of trans-genes in transformed Sinapis lines.Abbreviations BAP
6-benzylaminopurine
- CaMV
cauliflower mosaic virus
- GUS
-glucuronidase
- IBA
indole-3-butyric acid
- IM
infection medium
- NAA
1-naphthalene acetic acid
-
neo
gene encoding NPTII
- NPTII
neomycin phosphotransferase
- RIM
root-inducing medium
- SEM
shoot-elongation medium
- SIM
shoot-inducing medium
- t-nos
polyadenylation site of the nopaline synthase gene
-
uidA
gene encoding GUS
- WM
wash medium
- X-Gluc
5-bromo-4-chloro-3-indolyl -D-glucuronide 相似文献
7.
Summary Callus was initiated from in vitro-grown plants of Gladiolus cultivars ‘Jenny Lee’ and ‘Florida Flame.’ The age of callus used for regeneration of plants was either 9 mo. old or 8 yr
old from ‘Jenny Lee,’ and 4 mo. old from ‘Florida Flame.’ Regeneration medium consisted of Murashige and Skoog’s basal salts
medium supplemented with 2.0 mg/l (9.3 μM) kinetin. This medium was supplemented with various concentrations of either bialaphos (Meiji Seika, Tokyo, Japan) or phosphinothricin
(Hoechst-Roussell, Frankfurt, Germany). Bialaphos was more effective than phosphinothricin at stimulating plant regeneration.
Plants regenerated from 8-yr-old callus of ‘Jenny Lee’ only when the regeneration medium was supplemented with 0.10 mg/l bialaphos.
A bialaphos concentration of 0.01 mg/l stimulated regeneration from 9-mo.-old callus of cultivar ‘Jenny Lee’ and 4-mo.-old
callus of ‘Florida Flame.’ 相似文献
8.
The effect of light on the metabolism of ammonia was studied by subjecting detached maize leaves to 150 or 1350 mol m–2 s–1 PAR during incubation with the leaf base in 2 mM 15NH4Cl. After up to 60 min, leaves were extracted. Ammonia, glutamine, glycine, serine, alanine, and aspartate were separated by isothermal distillation and ion exchange chromatography. 15N enrichments were analyzed by emission spectroscopy. The uptake of ammonium chloride did not influence CO2 assimilation (8.3 and 17.4 mol m–1 s–1 at 150 and 1350 mol m–2 s–1 PAR, respectively). Leaves kept at high light intensity contained more serine and less alanine than leaves from low light treatments. Within 1 h of incubation the enrichment of ammonia extracted from leaves rose to approximately 20% 15N. In the high light regime the amino acids contained up to 15% 15N, whereas in low light 15N enrichments were small (up to 6%). The kinetics of 15N incorporation indicated that NH3 was firstly assimilated into glutamine and then into glutamate. After 15 min 15N was also found in glycine, serine and alanine. At high light intensity nearly half of the 15N was incorporated in glycine. On the other hand, at low light intensity alanine was the predominant 15N sink. It is concluded that light influences ammonia assimilation at the glutamine synthetase reaction. 相似文献
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Nitrogen fixation (measured as acetylene reduction) by whole nodulated alfalfa plants was stimulated when the plants were treated with isonicotinic acid hydracide (INH) and glyoxylate, both inhibitors of the glycolate pathway of carbohydrate metabolism, at concentrations of 300 and 100 mM, respectively. Reducing energetic loses caused by photorespiration results in an increase in the symbiotic nitrogen fixation.Abbreviation INH
isonicotinic acid hydracide 相似文献
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Belinda Martineau H. Jane Smith Caroline Dean Pamela Dunsmuir John Bedbrook Laurens J. Mets 《Plant molecular biology》1989,13(4):419-426
We report the successful transformation, via Agrobacterium tumefaciens infection, and regeneration of two species of the genus Flaveria: F. brownii and F. palmeri. We document the expression of a C3 plant gene, an abundantly expressed ribulose 1,5-bisphosphate carboxylase/oxygenase small subunit gene isolated from petunia, in these C4 plants. The organ-specific expression of this petunia gene in Flaveria brownii is qualitatively identical to its endogenous pattern of expression. 相似文献
13.
The carbon and nitrogen partitioning characteristics of wheat (Triticum aestivum L.) and maize (Zea mays L.) grown hydroponically at a constant pH on either 4 mM or 12 mM NO3
- or NH4
+ nutrition were investigated using either 14C or 15N techniques. Greater allocation of 14C to amino-N fractions occurred at the expense of allocation of 14C to carbohydrate fractions in NH4
+-compared to NO3
--fed plants. The [14C]carbohydrate:[14C]amino-N ratios were 1.5-fold and 2.0-fold greater in shoots and roots respectively of 12 mM NO3
--compared to 12 mM NH4
+-fed wheat. In both 4 mM and 12 mM N-fed maize the [14C]carbohydrate:[14C]amino-N ratios were approximately 1.7-fold and 2.0-fold greater in shoots and roots respectively of NO3
--compared to NH4
+-fed plants. Similar results were observed in roots of wheat and maize grown in split-root culture with one root-half in NO3
--and the other in NH4
+-containing nutrient media. Thus the allocation of carbon to the amino-N fractions occurred at the expense of carbohydrate fractions, particularly within the root. Allocation of 14N and 15N within separate sets of plants confirmed that NH4
--fed plants accumulated more amino-N compounds than NO3
--fed plants. Wheat roots supplied with 15NH4
+ for 8 h were found to accumulate 15NH4
+ (8.5 g 15N g-1 h-1) whereas in maize roots very little 15NH4
+ accumulated (1.5 g 15N g-1 h-1)It is proposed that the observed accumulation of 15NH4
+ in wheat roots in these experiments is the result of limited availability of carbon within the roots of the wheat plants for the detoxification of NH4
+, in contrast to the situation in maize. Higher photosynthetic capacity and lower shoot: root ratios of the C4 maize plants ensure greater carbon availability to the root than in the C3 wheat plants. These differences in carbon and nitrogen partitioning between NO3
--and NH4
+-fed wheat and maize could be responsible for different responses of wheat and maize root growth to NO3
- and NH4
+ nutrition. 相似文献
14.
The inhibitory effect of DL-phosphinothricin (glufosinate) on glutathione synthesis was studied in vivo and in vitro. The influence of phosphinothricin on γ-glutamylcysteine synthetase was compared with the already known effects of l -buthionine sulfoximine and l -methionine sulfoximine. The results showed that phosphinothricin and buthionine sulfoximine are inhibitors of γ-glutamylcysteine synthetase of plants. With both substances the enzyme was inhibited by 50 % at a concentration of 7 . 10?4M (pI50 = 3.15). Methionine sulfoximine reduced the enzyme activity by 50% at 5 . 10?2 M (pI50 = 1.30). It is discussed that the target enzyme of phosphinothricin is the glutamine synthetase whereas the γ-glutamylcysteine synthetase is only an accessory target. 相似文献
15.
(Benzamidooxy)acetic acid (common name benzadox) which has herbicidal properties was evaluated as a potential inhibitor of photosynthesis in C4 plants. Among enzymes of the C4 pathway, it was a relatively strong inhibitor of alanine aminotransferase in in vitro experiments at concentrations of 5mM. In benzadox treated leaves of Panicum miliaceum, a NAD-malic enzyme type C4 species, there was strong inhibition of both alanine and aspartate aminotransferase and of photosynthetic O2 evolution within one hour. Consistent with the inhibition of these enzymes of the C4 cycle, the pool sizes of metabolites of the cycle was altered: the aspartate level was increased two fold, while the levels of other metabolites such as pyruvate, alanine, oxalacetate and malate were decreased. Kinetic studies with partially purified alanine aminotransferase showed that benzadox is a competitive inhibitor with respect to alanine and a noncompetitive inhibitor with respect to 2-oxoglutarate. Comparisons between the structures and inhibitory actions of benzadox and (aminooxy)acetic acid, the latter a potent inhibitor of alanine and aspartate aminotransferases, suggest that in vivo, benzadox may exert its effect through metabolism to (aminooxy)acetic acid.Abbreviations benzadox
(benzamidooxy)acetic acid
- DTE
dithioerythritol
This research was supported in part by gift funds from Monsanto Agricultural Products Company. St. Louis, Missouri, and by NSF Grant PCM-8107953. 相似文献
16.
The metabolism of 14CO2 in the cool temperate saltmarsh grass Spartina townsendii was investigated in plants grown in their natural habitats at two temperatures. Both in the spring at 10°C and in the late summer at 25°C radioactivity was initially incorporated into the organic acids malate and aspartate and then transferred to 3-phosphoglycerate in the manner characteristic of the C4 pathway of photosynthesis. Metabolism was not disrupted at the lower temperature as in some C4 plants. Radioactivity was transferred more slowly from malate into alanine, glycine and serine at 10°C, but sugars were labelled equally at both temperatures. 相似文献
17.
Diffusive and metabolic limitations to photosynthesis under drought and salinity in C(3) plants 总被引:13,自引:0,他引:13
Drought and salinity are two widespread environmental conditions leading to low water availability for plants. Low water availability is considered the main environmental factor limiting photosynthesis and, consequently, plant growth and yield worldwide. There has been a long-standing controversy as to whether drought and salt stresses mainly limit photosynthesis through diffusive resistances or by metabolic impairment. Reviewing in vitro and in vivo measurements, it is concluded that salt and drought stress predominantly affect diffusion of CO(2) in the leaves through a decrease of stomatal and mesophyll conductances, but not the biochemical capacity to assimilate CO(2), at mild to rather severe stress levels. The general failure of metabolism observed at more severe stress suggests the occurrence of secondary oxidative stresses, particularly under high-light conditions. Estimates of photosynthetic limitations based on the photosynthetic response to intercellular CO(2) may lead to artefactual conclusions, even if patchy stomatal closure and the relative increase of cuticular conductance are taken into account, as decreasing mesophyll conductance can cause the CO(2) concentration in chloroplasts of stressed leaves to be considerably lower than the intercellular CO(2) concentration. Measurements based on the photosynthetic response to chloroplast CO(2) often confirm that the photosynthetic capacity is preserved but photosynthesis is limited by diffusive resistances in drought and salt-stressed leaves. 相似文献
18.
The effect of drought on the photosynthetic functioning of two C3 plants, Phaseolus vulgaris and Elatostema repens, has been examined. Leaf net CO2 uptake measured in normal air was negligible at a leaf water deficit of about 30% while the calculated leaf intercellular CO2 concentration (Ci) was unchanged. However, both the maximal photosynthetic capacity (CO2-dependent O2 evolution) and apparent quantum yield, measured in the presence of saturating CO2 levels (5 to 14%), only started to decrease within the range of 25 to 30% leaf water deficit. This shows that the drought-induced inhibition seen in normal air is not caused by an inhibition of the photosynthetic mechanism, and that in this case Ci values can be misleading. Both 77 K and room-temperature fluorescence measurements indicate that the functioning of the photosystem-II reaction centre is hardly modified by water shortage. Furthermore, an analysis of photochemical chlorophyll fluorescence quenching shows, in the absence of CO2, that O2 can be an efficient acceptor of photosynthetic energy, even in severly dehydrated plants which do not show net CO2 uptake in normal air. In these plants, O2 is probably reduced mainly via Mehler-type reactions. High-light treatment given at low O2 increases photoinhibition as measured by the decrease of apparent quantum yield in dehydrated P. vulgaris, whereas, interestingly, 1% O2 protects dehydrated E. repens against high-light damage. The two plants could have different protective mechanisms depending upon the O2 level or different photoinhibitory sites or mechanisms.Abbreviations and symbols Ca, Ci
ambient and calculated intercellular CO2 concentration
- Fm, Fo, Fv
maximum, initial and variable fluorescence emission
- LWD
leaf water deficit
- PPFD
photosynthetic photon flux density
- PSII
photosystem II
- qQ
photochemical quenching of chlorophyll fluorescence 相似文献
19.
The effects of root applications of gibberellic acid (GA3) on growth and photosynthesis of 12 species of plants including C3 monocots (Triticum aestivum L., wheat, Hordeum vulgare L., barley and Avena sativa L., oat), C3 dicots (Vigna radiata L., mung bean, Cucurbita moschata L., squash and Capsicum annuum L., pepper), C4 monocots (Zea mays L., corn, Sorghum vulgare L., sorghum and Panicum ramosum L., millet) and C4 dicots (Amaranthus retroflexus L., pigweed, Kochia scoparis L., kochia and Gomphrena celosoides L., gomphrena) were evaluated. Relative growth rates (RGR) of barley, oat, squash, pepper, corn, sorghum, millet, pigweed and kochia were increased above the control by 12.7%, 9.9%, 11.3%, 10.7%, 19.2% 10.1%, 11.5%, 16.4% and 32.7% respectively, four days following optimum GA3 treatments. There was no effect of GA3 on RGR in wheat, mung bean, and gomphrena. Gibberellic acid decreased the chlorophyll content expressed on an area basis by 20.0%, 13.9%, 20.9%, 17.1%, 11.9% and 28.0% in barley, squash, pepper, sorghum, pigweed and kochia, respectively, while that of oat, wheat, mung bean, corn, millet and gomphrena remained unchanged. When photosynthetic rates were expressed per mg of chlorophyll, it showed that GA3 could stimulate photosynthesis in barley, squash, pepper, sorghum, millet, pigweed and kochia by 20.4%, 20.6%, 16.5%, 17.4%, 10.4%, 24.2%, and 29.4%; while there was no effect in oat, wheat, mung bean, corn and gomphrena. An increase in leaf blade area and/or length of sheath were observed in GA3 treated plants of oat, barley, mung bean, squash, pepper, corn, sorghum, millet and kochia. The transpiration rate remained unchanged following GA3 treatment in all 12 species.This work was supported in part by the Fair Funds administered by the Pennsylvania Department of Agriculture. Contribution No. 39, Department of Horticulture, The Pennsylvania State University. Authorized for publications as paper no. 6886 in the journal series of the Pennsylvania Agricultual Experiment Station.Research assistant and assistant professor respectively. 相似文献
20.
Background and Aims: The grass Alloteropsis semialata is the only plant species withboth C3 and C4 subspecies. It therefore offers excellent potentialas a model system for investigating the genetics, physiologyand ecological significance of the C4 photosynthetic pathway.Here, a molecular phylogeny of the genus Alloteropsis is constructedto: (a) confirm the close relationship between the C3 and C4subspecies of A. semialata; and (b) infer evolutionary relationshipsbetween species within the Alloteropsis genus. Methods: The chloroplast gene ndhF was sequenced from 12 individuals,representing both subspecies of A. semialata and all four ofthe other species in the genus. ndhF sequences were added tothose previously sequenced from the Panicoideae, and used toconstruct a phylogenetic tree. Key Results: The phylogeny confirms that the two subspecies of A. semialataare among the most recently diverging lineages of C3 and C4taxa currently recognized within the Panicoideae. Furthermore,the position of the C3 subspecies of A. semialata within theAlloteropsis genus is consistent with the hypothesis that itsphysiology represents a reversion from C4 photosynthesis. Thedata point to a similar evolutionary event in the Panicum stenodes–P.caricoides–P. mertensii clade. The Alloteropsis genusis monophyletic and occurs in a clade with remarkable diversityof photosynthetic biochemistry and leaf anatomy. Conclusions: These results confirm the utility of A. semialata as a modelsystem for investigating C3 and C4 physiology, and provide moleculardata that are consistent with reversions from C4 to C3 photosynthesisin two separate clades. It is suggested that further phylogeneticand functional investigations of the Alloteropsis genus andclosely related taxa are likely to shed new light on the mechanismsand intermediate stages underlying photosynthetic pathway evolution. 相似文献