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1.
Short-term discrimination in assimilation of stable isotopes of carbon was measured for leaves of the C 3 species Phaseolus vulgaris L. cv. Hawkesbury Wonder and Flaveria pringlei Gandoger, the C 4 species Amaranthus edulis Speg., and the C 3–C 4 intermediate species Panicum milioides Nees ex. Trin, Flaveria floridana Johnson, and Flaveria anomala B.L. Robinson. Discriminations in the C 3 and C 4 species were similar to those expected from theoretical considerations. When ambient CO 2 pressure was 330 bar the mean discriminations in the C 3 species and Panicum milioides were similar, whereas the mean discriminations in F. floridana and F. anomala were less than discrimination in C 3 species and Panicum milioides. When ambient CO 2 pressure was 100 bar the mean discriminations in Panicum milioides and F. anomala were greater, and that in F. floridana was less, than that in Phaseolus vulgaris. We conclude that the pattern of discrimination in Panicum milioides is consistent with the presence of a glycine shuttle; in F. floridana and F. anomala, discrimination is consistent with the presence of a C 4 pathway coupled with the operation of a glycine shuttle.Abbreviations and symbols PEP
phosphoenolpyruvate
- Rubisco
ribulose, 1,5-bisphosphate carboxylase-oxygenase (EC 4.1.1.39)
-
p
a
ambient CO 2 pressure
-
p
i
intercellular CO 2 pressure
-
carbon-isotope discrimination
-
carbonisotope composition relative to PeeDee Belemnite 相似文献
2.
介绍了有关C3、C4和C3-C4中间型植物进化的形态学、生理学、分子生物学、遗传学等方面的证据;推断地球上首先出现C3植物,然后是C3-C4中间类型植物,最后出现C4植物. 相似文献
3.
The in-situ inter- and intracellular localization patterns of phosphoenolpyruvate (PEP) and ribulose 1,5-bisphosphate (RuBP) carboxylases in green leaves of several Panicum species were investigated using an indirect immunofluorescence technique. Four species were examined and compared: P. miliaceum (C 4), P. bisulcatum (C 3), and P. decipiens and P. milioides (C 3–C 4 intermediates which have Kranz-like leaf anatomy and reduced photorespiration). In the C 4
Panicum, PEP carboxylase was located in the cytosol of the mesophyll cells and RuBP carboxylase was restricted to the bundle-sheath chloroplasts. In contrast, in the C 3
Panicum species, PEP carboxylase was found throughout the leaf chlorenchyma, in both the cytosol and chloroplasts, and RuBP carboxylase was located in the chloroplasts. For the C 3–C 4 intermediate plants, the patterns depended on the species examined. For P. decipiens, the in-situ localization of both carboxylases was similar to that described for P. bisulcatum and other C 3 plants. However, in P. milioides, PEP carboxylase was found exclusively in the cytosol of the mesophyll cells, as in P. miliaceum and other C 4 species, whereas RuBP carboxylase was distributed in both the mesophyll and bundle-sheath chloroplasts.Abbreviations PEP
phosphoenolpyruvate
- RuBP
ribulose 1,5-bisphosphate 相似文献
5.
The Chenopodiaceae is one of the families including C4 species among eudicots. In this family, the genus Chenopodium is considered to include only C3 species. However, we report here a transition from C3 photosynthesis to proto-Kranz to C3–C4 intermediate type in Chenopodium. We investigated leaf anatomical and photosynthetic traits of 15 species, of which 8 species showed non-Kranz anatomy and a CO2 compensation point (Γ) typical of C3 plants. However, 5 species showed proto-Kranz anatomy and a C3-like Γ, whereas C. strictum showed leaf anatomy and a Γ typical of C3–C4 intermediates. Chenopodium album accessions examined included both proto-Kranz and C3–C4 intermediate types, depending on locality. Glycine decarboxylase, a key photorespiratory enzyme that is involved in the decarboxylation of glycine, was located predominantly in the mesophyll (M) cells of C3 species, in both M and bundle-sheath (BS) cells in proto-Kranz species, and exclusively in BS cells in C3–C4 intermediate species. The M/BS tissue area ratio, number of chloroplasts and mitochondria per BS cell, distribution of these organelles to the centripetal region of BS cells, the degree of inner positioning (vacuolar side of chloroplasts) of mitochondria in M cells, and the size of BS mitochondria also changed with the change in glycine decarboxylase localization. All Chenopodium species examined were C3-like regarding activities and amounts of C3 and C4 photosynthetic enzymes and δ13C values, suggesting that these species perform photosynthesis without contribution of the C4 cycle. This study demonstrates that Chenopodium is not a C3 genus and is valuable for studying evolution of C3–C4 intermediates. 相似文献
6.
The assimilation of 14CO 2 into the C 4 acids malate and aspartate by leaves of C 3, C 4 and C 3–C 4 intermediate Flaveria species was investigated near the CO 2 compensation concentration * in order to determine the potential role of phosphoenolpyruvate (PEP) carboxylase (EC 4.1.1.31) in reducing photorespiration in the intermediates. Relative to air concentrations of CO 2, the proportion of CO 2 fixed by PEP carboxylase at * increased in all six C 3–C 4 intermediate species examined. However, F. floridana J.R. Johnston and F. ramosissima Klatt were shown to be markedly less responsive to reduced external CO 2, with only about a 1.6-fold enhancement of CO 2 assimilation by PEP carboxylase, as compared to a 3.0- to 3.7-fold increase for the other C 3–C 4 species examined, namely, F. linearis Lag., F. anomala B.L. Robinson, F. chloraefolia A. Gray and F. pubescens Rydb. The C 3 species F. pringlei Gandoger and F. cronquistii A.M. Powell exhibited a 1.5- and 2.9-fold increase in labeled malate and aspartate, respectively, at *. Assimilation of CO 2 by PEP carboxylase in the C 4 species F. trinervia (Spreng.) C. Mohr, F. australasica Hook., and the C 4-like species F. brownii A.M. Powell was relatively insensitive to subatmospheric levels of CO 2. The interspecific variation among the intermediate Flaverias may signify that F. floridana and F. ramosissima possess a more C 4-like compartmentation of PEP carboxylase and ribulose-1,5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39) between the mesophyll and bundle-sheath cells. Chasing recently labeled malate and aspartate with 12CO 2 for 5 min at * resulted in an apparent turnover of 25% and 30% of the radiocarbon in these C 4 acids for F. ramosissima and F. floridana, respectively. No substantial turnover was detected for F. linearis, F. anomala, F. chloraefolia or F. pubescens. With the exception of F. floridana and F. ramosissima, it is unlikely that enhanced CO 2 fixation by PEP carboxylase at the CO 2 compensation concentration is a major mechanism for reducing photorespiration in the intermediate Flaveria species. Moreover, these findings support previous related 14CO 2-labeling studies at air-levels of CO 2 which indicated that F. floridana and F. ramosissima were more C 4-like intermediate species. This is further substantiated by the demonstration that F. floridana PEP carboxylase, like the enzyme in C 4 plants, undergoes a substantial activation (2.2-fold) upon illuminating dark-adapted green leaves. In contrast, light activation was not observed for the enzyme in F. linearis or F. chloraefolia.Abbreviations and symbols PEP
phosphoenolpyruvate
- Rubisco
ribulose-1,5-bisphosphate carboxylase/oxygenase
-
CO 2 compensation concentration
- *
a subatmospheric level of CO 2 approximating
Published as Paper No. 8832, Journal Series, Nebraska Agricultural Research Division 相似文献
7.
Summary
C'3 phenotype and gene frequencies observed in two Italian samples are reported. The allele frequencies resemble those reported for other Caucasian populations. Five different rare variants are described. 相似文献
8.
Phosphoenolpyruvate carboxylase (PEPCase; EC 4.1.1.31) from Flaveria trinervia Mohr (C 4), F. floridana Johnston (C 3–C 4), and F. cronquistii Powell (C 3) leaves were compared by electrotransfer blotting/enzyme-linked immunoassay (Western-blot analysis), mobility of the native enzyme in polyacrylamide gels and in isoelectric focusing (IEF) gels, peptide mapping, and in-vitro translation of RNA isolated from each plant. The PEPCases from the C 3 and C 3–C 4 plants were very similar to each other in terms of electrophoretic mobilities on gels and isoenzyme patterns on IEF gels, and identical in peptide mapping. Quantitative differences were noted, however, in that the C 3–C 4 intermediate plant contained more PEPCase overall and that the relative activity of individual isoenzymes shifted between the C 3 and C 3–C 4 intermediate PEPCases. The PEPCase from the C 4 plant had a different isoenzyme pattern, a different peptide map, and was far more abundant than the other two enzymes. Western blot analysis demonstrated the cross-reactivity of PEPCases from all three Flaveria species with antibody raised against maize PEPCase. The results provide evidence, at the molecular level, that supports the view of C 3–C 4 intermediate species as C 3-like plants with some C 4-like photosynthetic characteristics, but there are differences from the C 3 plant in the quantity and properties of the PEPCase from the C 3–C 4 intermediate plant.Abbreviations IEF
isoelectric focusing
- kDa
kilodalton
- PEPCase
phosphoenolpyruvate carboxylase
- Rubisco
Ribulose-1,5-bisphosphate carboxylase/oxygenase 相似文献
9.
综述了C3植物中C4途径的发现及研究现状;阐述了C3植物中C4途径的几种作用机理;根据C3植物中C4途径的存在,探讨了改造C3植物的遗传特性;并展望了这一领域的研究前景。 相似文献
10.
综述了C3植物中C4途径的发现及研究现状:阐述了C3植物中C4途径的几种作用机理;根据C3植物中C4途径的存在,探讨了改造C3植物的遗传特性;并展望了这一领域的研究前景。 相似文献
11.
在农业实践和科学研究中经常需要知道某种植物是C_3植物还是C_4植物,例如在干旱少雨的地区种植C_4作物就易获得较高的产量;用甲醇喷洒植物能使植物增产,但这种技术只适用于C_3植物而不适用于C_4植物等。从理论上讲,C_3植物光合作用固定CO_2的最初产物是三碳的3—磷酸甘油酸,C_4植物光合作用固定CO_2的最初产物是四碳的苹果酸或天冬氨酸。我们在研究农田杂草光合碳同化途径时,摸索了一些快速区分C_3植物与C_4植物的经验,介绍如下。 从植物进化方面区分 我们知道,C_3植物较原始,C_4植物较进化,实际上较原始的蕨类植物和裸子植物就没有C_4植物,只有较进化 相似文献
12.
C_3和C_4植物的氮素利用效率何新华,AnnOaks,李明启(云南师范大学生物系,昆明650092)(圭尔夫大学植物系,加拿大NIG2W1)(华南农业大学农业生物系,广州510642)关键词C_3和C_4植物,NO吸收与积累,硝酸还原酶酶蛋白,硝酸... 相似文献
13.
The concentrations of 17 nucleotides and three nucleosides have been determined in a batch suspension culture of Datura innoxia using a new procedure for extraction, purification and high-performance liquid chromatography separation of these compounds. The nucleotide pools change appreciably in the different phases of growth. These changes indicate the preparation for and initiation of cell proliferation, and reflect metabolic events during cell division, cell elongation and starvation. The main components of the nucleotide pool are uracil nucleotides, with uridine 5-diphosphate sugars as the predominant fraction, and the adenine nucleotides. Although their concentrations vary by a factor of more than 6 the ratio of the uracil to adenine nucleotides is kept fairly constant during growth. The energy charge is maintained at a rather high value. The correlation of these events with nutrient uptake and macromolecular synthesis by the batch culture is presented in the following paper.Abbreviations Glc
glucose
- GlcNAc
2-acetamido-2-deoxy- d-glucose
- HPLC
high performance liquid chromatography
- UDP
uridine 5-diphosphate 相似文献
15.
Significant night-time stomatal conductance and transpiration were found for 11 out of 17 species with a range of life histories (herbaceous annual, perennial grass, shrub, tree), photosynthetic pathways (C(3), C(4)), and habitats in the western United States. Across species and habitats, higher night-time conductance and transpiration were associated with higher daytime values. The prevalence, mechanisms and ecological implications of substantial night-time water loss deserve further investigation. 相似文献
16.
The relationship between the gas-exchange characteristics, the contents of photosynthetic intermediates and the quantum yield of photosystem II was examined at different intercellular partial pressures of CO 2 ( p
i) in attached leaves of Moricandia arvensis L. (D.C.) and Flaveria floridana J.R. Johnson (both C 3–C 4 intermediate plants) and, for comparison, in F. pringlei Gandoger (a C 3 plant) and in F. bidentis (a C 4 plant). Both C 3–C 4 intermediate species had pools of phosphoenolpyruvate, pyruvate, alanine and aspartate intermediate to those of the C 3 and C 4 species examined. Moricandia arvensis had large pools of glycine at low p
i, consistent with the operation of a glycine shuttle from mesophyll to bundle-sheath cells. It also had a high pool of triose-phosphate at ambient partial pressures of CO 2, indicating that a glycerate-3-phosphate/triose-phosphate shuttle could operate in this species. This was not the case in F. floridana. A decline in the ribulose-1,5-bisphosphate and triose-phosphate pool in M. arvensis, and a rise in the pools of glycerate-3-phosphate and pyruvate in F. floridana, at low p
i, show different patterns of metabolic regulation in M. arvensis and F. floridana at low p
i in comparison to C 3 and C 4 plants.Abbreviations Frul,6bisP
fructose-1,6-bisphosphate
- PEP
phosphoenolpyruvate PGA-glycerate-3-phosphate
-
p
i
intercelular CO 2 pressure
- PPFD
photosynthetic photon flux density;
- RuBP
ribulose-1,5-bisphosphate
- triose-P
triose phosphates
This work was done while R.C.L. was a Visiting Fellow at the Australian National University, and was sponsored by the Royal Society. We are grateful to Kathy Britt for assistance with the analysis of amino acids. 相似文献
17.
针对目前植物生理学教材中很少提及的C3-C4中间型植物,从概念、主要特征及研究价值方面作基本介绍,为课程讲解提供参考. 相似文献
18.
C_3和C_4禾本科作物的氮素利用效率何新华安·奥克斯(云南师范大学生命科学系,昆明650092)(加拿大圭尔夫大学植物系圭尔夫NlG.ZA1)李明启(华南农业大学农业生物系广州510642)THEEFFCIENCYOFNITROGENUTILIZA... 相似文献
19.
提高植物的氮素利用效率(NUE)不仅有利于保障全球粮食安全, 也是实现农业可持续发展的重要途径。近半个世纪以来, 植物氮素利用机理研究已取得重要进展, 但NUE的调控机制仍不明确, NUE的提高仍然十分有限。高等植物集光合碳素同化和氮素同化于一体, 只有碳氮代谢相互协调, 才能维持植物体内的碳氮平衡, 保证植物正常生长发育。由于C 3和C 4植物的光合氮素利用率(PNUE)存在差异, 对氮素的利用效率也会存在差异。为了更有效地提高作物的NUE, 须更全面地了解C 3和C 4植物对氮素吸收、转运、同化和信号转导等关键因子的功能和调控机制。此外, 面对大气CO 2浓度增高和全球气候变暖条件下的植物碳氮同化及其机理的研究也不容忽视。该文综述了C 3和C 4植物氮素利用关键因素的差异及其调控机制, 并对提高C 3禾本科作物氮素利用效率的遗传改良途径进行了展望。 相似文献
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