共查询到20条相似文献,搜索用时 15 毫秒
1.
In a study on metabolic consumption of photosynthetic electronsand dissipation of excess light energy under water stress, O 2and CO 2 gas exchange was measured by mass spectrometry in tomatoplants using 18O 2 and 13CO 2. Under water stress, gross O 2 evolution(E O), gross O 2 uptake (U O), net CO 2 uptake (P N), gross CO 2 uptake(TPS), and gross CO 2 evolution (E C) declined. The ratio P N/E Ofell during stress, while the ratios U O/E O and E C/TPS rose.Mitochondrial respiration in the light, which can be measureddirectly by 12CO 2 evolution during 13CO 2 uptake at 3000 µll 1 13CO 2, is small in relation to gross CO 2 evolutionand CO 2 release from the glycolate pathway. It is concludedthat PSII, the Calvin cycle and mitochondrial respiration aredown-regulated under water stress. The percentages of photosyntheticelectrons dissipated by CO 2 assimilation, photorespiration andthe Mehler reaction were calculated: in control leaves morethan 50 % of the electrons were consumed in CO 2 assimilation,23 % in photorespiration and 13 % in the Mehler reaction. Undersevere stress the percentages of electrons dissipated by CO 2assimilation and the Mehler reaction declined while the percentageof electrons used in photorespiration doubled. The consumptionof electrons in photorespiration may reduce the likelihood ofdamage during water deficit. 相似文献
2.
The effects of elevated carbon dioxide (CO 2 and ozone (O 3) onsoybean ( Glycine max (L.) Merr.] photosynthesis and photorespiration-relatedparameters were determined periodically during the growing seasonby measurements of gas exchange, photorespiratory enzyme activitiesand amino acid levels. Plants were treated in open-top fieldchambers from emergence to harvest maturity with seasonal meanconcentrations of either 364 or 726 µmol mol 1 CO 2in combination with either 19 or 73 nmol mol 1 O 3 (12h daily averages). On average at growth CO 2 concentrations,net photosynthesis ( A) increased 56% and photorespiration decreased36% in terminal mainstem leaves with CO 2 enrichment. Net photosynthesisand photorespiration were suppressed 30% and 41%, respectively,by elevated O 3 during late reproductive growth in the ambientCO 2 treatment, but not in the elevated CO 2 treatment. The ratioof photorespiration to A at growth CO 2 was decreased 61% byelevated CO 2 There was no statistically significant effect ofelevated O 3 on the ratio of photorespiration to A. Activitiesof glycolate oxidase, hydroxypyruvate reductase and catalasewere decreased 1025% by elevated CO 2 and by 4666%by elevated O 3 at late reproductive growth. The treatments hadno significant effect on total amino acid or glycine levels,although serine concentration was lower in the elevated CO 2and O 3 treatments at several sampling dates. The inhibitoryeffects of elevated O 3 on photorespiration-related parameterswere generally commensurate with the O 3-induced decline in A.The results suggest that elevated CO 2 could promote productivityboth through increased photoassimilation and suppressed photorespiration. Key words: Photorespiration, CO 2-enrichment, ozone, climate change, air pollution 相似文献
3.
Segments of wheat leaves were supplied in the light with 14C-labelledserine or glucose in atmospheres containing different concentrationsof O 2 and zero or 350 parts/10 6 CO 2. Some O 2 was necessary forsucrose synthesis from either serine or glucose but sucrosesynthesis from glucose depended on reactions with a high affinityfor O 2 whereas sucrose synthesis from serine depended both onreactions with high and low affinities for O 2. In the presenceof CO 2 sucrose synthesis from serine was decreased when theO 2 concentration was increased from 20 to 80% by volume andCO 2 was liberated; sucrose synthesis from glucose was almostunaffected by the same change in conditions. Also, in an atmospherecontaining 80% O 2 and 350 parts/10 6 CO 2, radioactivity from[ 14C]serine, was incorporated into glycine. This was not truefor glucose feeding. Hence glucose provides a substrate forsucrose synthesis but not for photorespiration whereas serineis used for both processes in the presence of CO 2; in the absenceof CO 2 glucose provides substrate for both sucrose synthesisand photorespiration and serine metabolism to sucrose is restricted. 相似文献
4.
Although active oxygen species are produced at high rates inboth the chloroplasts and peroxisomes of the leaves of C 3 plants,most attention has focused on the potentially damaging consequencesof enhanced chloroplastic production in stress conditions suchas drought. This article attempts to provide quantitative estimatesof the relative contributions of the chloroplast electron transportchain and the glycolate oxidase reaction to the oxidative loadplaced on the photosynthetic leaf cell. Rates of photorespiratoryH 2O 2 production were obtained from photosynthetic and photorespiratoryflux rates, derived from steady-state leaf gas exchange measurementsat varying irradiance and ambient CO 2. Assuming a 10 % allocationof photosynthetic electron flow to the Mehler reaction, photorespiratoryH 2O 2 production would account for about 70 % of total H 2O 2 formedat all irradiances measured. When chloroplastic CO 2 concentrationrates are decreased, photorespiration becomes even more predominantin H 2O 2 generation. At the increased flux through photorespirationobserved at lower ambient CO 2, the Mehler reaction would haveto account for more than 35 % of the total photosynthetic electronflow in order to match the rate of peroxisomal H 2O 2 production.The potential signalling role of H 2O 2 produced in the peroxisomesis emphasized, and it is demonstrated that photorespiratoryH 2O 2 can perturb the redox states of leaf antioxidant pools.We discuss the interactions between oxidants, antioxidants andredox changes leading to modified gene expression, particularlyin relation to drought, and call attention to the potentialsignificance of photorespiratory H 2O 2 in signalling and acclimation. 相似文献
5.
Mutant barley plants containing only 8%, 16% or 38% of the wildtype level of glutamine synthetase activity have been isolated.The level of glutamine synthetase activity in the roots of themutant containing only 8% leaf activity was not affected bythis mutation. The plants accumulated high levels of ammoniain leaves exposed to air and although they were able to carryout photosynthetic CO 2fixation normally at low levels of atmosphericO 2, they were unable to maintain wild type rates of CO 2fixationin air. The extent of this inhibition and the extent to whichammonia accumulated in the leaves was dependent on the photonfluence rate intercepted by the plant. When leaves from themutant plant were fed glutamine under non-photorespiratory conditionsfor 40 min before they were transferred to air, the plants exhibitedwild type rates of CO 2 fixation in air but the ammonia contentof the leaves increased to an even higher level. At least inthe short term, therefore, ammonia accumulation was not responsiblefor the dramatic decline in the fixation rate of these mutantsin air. The most probable explanation is that as the supplyof potential amino donors diminished on transfer to air, therewas a restriction on the return of glycerate to the Calvin cyclewithin the chloroplast. Key words: Ammonia toxicity, photorespiration, photosynthesis, GS-deficient barley 相似文献
6.
Wheat plants were grown in a controlled environment with daytemperatures of 18 ?C and with 500 µ Einsteins m 28 1 of photosynthetically active radiation for 16 h. Beforeanthesis and 2 to 3 weeks after, rates of net photosynthesiswere measured for leaves in 2 or 21% O 2 containing 350 vpm CO 2at 13, 18, 23, and 28 ?C and with 500 µEinsteins m 2s 1 of photosynthetically active radiation. Also, underthe same conditions of light intensity and temperature, therates of efflux of CO 2 into CO 2-free air were measured and,for mature flag leaves 3 to 4 weeks after anthesis, gross andnet photosynthesis from air containing 320 vpm 14CO 2 of specificactivity 39?7 nCi µmol 1. When the O 2 concentration was decreased from 21 to 2% (v/v)the rate of net photosynthesis increased by 32 per cent at thelowest temperature and 54 per cent at the highest temperature.Efflux of CO 2 into CO 2-free air ranged from 38 per cent of netphotosynthesis at 13 ?C to 86 per cent at 28 ?C. Gross photosynthesis,measured by the 14C assimilated during 40 s, was greater thannet photosynthesis by some 10 per cent at 13 ?C and 17 per centat 28 ?C. These data indicate that photorespiration was relativelygreater at higher temperatures. 相似文献
7.
Attached leaves of sunflower ( Helianthus annuus L. var. Mennonite)with water potentials of 5 to 18 ? 10 5 Pa, wereexposed for different times to 300 vpm CO 2 containing 14CO 2and 21 or 1.5% O 2. 14C accumulated linearly with time in bothO 2 concentrations and at all stresses. 3-Phosphoglyceric acidwas saturated with 14C after 10 min in unstressed plants atboth O 2 concentrations but with increasing stress the rate ofaccumulation and the specific activity decreased. With decreasingleaf water potential there was accumulation of radioactivityin the glycolate pathway intermediates glycine and serine. Otheramino acids contained a slightly larger proportion of assimilatedcarbon as water potential decreased. The specific activitiesof all compounds were smaller with stress. In contrast to theamino acids less radioactivity accumulated in sugars, organicacids, and sugar phosphates and their specific activities decreasedwith stress. The radioactive labelling patterns and specificactivity measurements are interpreted as showing increased carbonflux in the glycolate pathway and inhibition of the metabolismof serine to sucrose. These changes are related to previousresults showing that with stress photo respiration increasesas a proportion of photosynthesis. Lowering the O 2 concentrationto 1.5% decreased the accumulation of radioactivity in glycineand stopped photorespiration. It increased the amount of radioactivityin serine and sucrose but did not greatly change specific activities.Oxygen effects were independent of water stress. Glycolate pathwaymetabolism is discussed in relation to photorespiration andthe effects of water stress. 相似文献
8.
Exposure to atmospheric conditions which promote photorespirationstrongly inhibits photosynthesis in a mutant of Arabidopsislacking mitochondrial serine transhydroxymethylase activity,and glycine accumulates as a stable end-product of photorespiratorycarbon and nitrogen flow. By providing exogenous serine andammonia to leaves of the mutant, wild-type photosynthesis ratescan be temporarily maintained in the absence of photorespiratoryCO 2 evolution. In these circumstances, the rate of glycine accumulationprovides a direct measure of photorespiratory flux which isnot complicated by the efflux and refixation of photorespiredCO 2, the dilution of radioactive label by endogenous metabolicpools, or non-specific effects of metabolic inhibitors. At thestandard atmospheric concentration of CO 2, the rate of glycineaccumulation in the mutant was proportional to the oxygen concentration,amounting to 53% of the rate of gross CO 2-fixation at 21% O 2.At normal levels of O 2, glycine accumulation was maximal atabout 475 µl CO 21 1 and was reduced at higher orlower CO 2 concentrations, being almost abolished at 3000µ1CO 21 1. These observations are discussed in the contextof a model of photorespiration based on the properties of ribulose1, 5-bisphosphate carboxylase/oxygenase, and in relation tothe results of previous attempts to measure photorespiration.Preliminary evidence from 14CO 2-labelling experiments whichsuggests a non-photorespiratory pathway of serine synthesisis also presented. Key words: Arabidopsis mutant, Photorespiration, Serine transhydroxymethylase 相似文献
9.
Photorespiration rates under air-equilibrated conditions (0.04%CO 2 and 21% O 2) were measured in Chlamydomonas reinhardtii wild-type2137, a phosphoglycolate-phosphatase-deficient ( pgp1) mutantand a suppressor double mutant (7FR2N) derived from the pgp1mutant. In both cells grown under 5% CO 2 and adapted air for24 h in the suppressor double mutant, the maximal rate of photorespiration(phosphoglycolate synthesis) was only about half of that ineither the wild type or the pgp1 mutant (18-7F) cells. In theprogeny, the reduced rate of photorespiration was accompaniedby increased photosynthetic affinity for inorganic carbon andthe capacity for growth under air whether accompanied by the pgp1 background or not. Tetrad analyses suggested that thesethree characteristics all resulted from a nuclear single-genemutation at a site unlinked to the pgp1 mutation. The decreasein photorespiration was, however, not due to an increase inthe CO 2/O 2 relative specificity of ribulose-1,5-bisphosphatecarboxylase/oxygenase of 7FR2N or of any other suppressor doublemutants tested. The relationship between the decrease in therate of photorespiration and the CO 2-concentrating mechanismis discussed.
3 Current address: Institute of Botany, Academy of Sciences,Patamdar Shosse, 40, Baku, 370073, Azerbaijan.
4 Current address: Department of Management and InformationScience, Jobu University, 270-1, Shinmachi, Tano, Gunma, 370-1393Japan. 相似文献
10.
Substrates for photorespiration were examined by feeding 14Clabeled compounds to tobacco and corn leaf segments and by measuring 14CO 2 evolution in light and darkness. CO 2 release in the darkwas rapid, but in light CO 2 release was slow due to refixationby photosynthesis. Carboxyl labeled glycine was more rapidlydecarboxylated than were glyoxylate, glycolate or serine. Hydroxypyridinemethanesulfonate, an inhibitor of glycolate oxidase, blocked CO 2 releasefrom glycolate but not from glycine. Isonicotynyl hydrazideblocked CO 2 release from both glycine and glycolate. DCMU blockedphotosynthetic refixation of the released CO 2, consequentlythe rates of CO 2 release in light and dark were about equal.It was concluded that CO 2 release during photo-respiration camefrom the conversion of 2 molecules of glycine to one serineand one CO 2. 14CO 2 release from glycine-l- 14C in the dark or with DCMU inlight can be used as an assay for photorespiration ability. CO 2 release from glycine and glycolate by corn leaf segmentsin the dark proceeded at the rate of that in normal tobaccoleaf. This result, together with other work on O 2 exchange andenzymatic analysis, indicates that corn and other plants docarry on photorespiration, but it is not manifested by CO 2 releasein light. A yellow tobacco mutant, Consolation 402, had high rates ofphotorespiration by the 14CO 2 assay, nearly half (or more) asmany peroxisomes as chloroplasts, and high rates of CO 2 releasefrom glycine-l- 14C or glycolate-l- 14C. A common tobacco, BrightYellow, had lower rates of photorespiration, fewer visible peroxisomes,and slower decarboxylation of glycine and glycolate. The amount of 14CO 2 release from glycine-l- 14C or glycolate-l- 14Cincreased only slightly when the temperature was raised from25 to 35°C.
1Parts of this work were abstracted at the Annual Meeting (April,1969) of Japanese Society of Plant Physiologists, Kanazawa
2Department of Biochemistry, Michigan State University, EastLansing, Michigan, U.S.A. (Received September 3, 1969; ) 相似文献
11.
光呼吸(photorespiration)是绿色植物在光下吸收氧气并释放CO 2的过程。C 3植物光呼吸可消耗25%光合产物, 故合理改良光呼吸可望提高植物的光合效率。筛选与利用光呼吸突变体是研究光呼吸代谢及其功能的最为有效的途径。该文对光呼吸代谢途径、光呼吸突变体的筛选以及研究进展进行综述, 以期为深入探讨植物光呼吸的生物学功能及进行植物分子改良提供帮助。 相似文献
12.
A model for leaf photosynthesis by C 3 plant species is usedto examine the inter-relations between carbon dioxide and oxygenconcentrations, and dark respiration rates at the leaf compensationpoint. The model is applied to data published on a range ofC 3 plant types. These data indicate a remarkable constancy inthe slope of linear relationship between the CO 2 and O 2 concentrationsat the leaf compensation point, indicating a constancy in theratio of photorespiration to photosynthesis across C 3 planttypes. The model is extended to deal with C 4 plants and used to interpretthe differences in the compensation point relationships of C 3and C 4 plants. 相似文献
13.
Light-dependent O 2 exchange was measured in intact, isolated soybean ( Glycine max. var. Williams) cells using isotopically labeled O 2 and a mass spectrometer. The dependence of O 2 exchange on O 2 and CO 2 was investigated at high light in coupled and uncoupled cells. With coupled cells at high O 2, O 2 evolution followed similar kinetics at high and low CO 2. Steady-state rates of O 2 uptake were insignificant at high CO 2, but progressively increased with decreasing CO 2. At low CO 2, steady-state rates of O 2 uptake were 50% to 70% of the maximum CO 2-supported rates of O 2 evolution. These high rates of O 2 uptake exceeded the maximum rate of O 2 reduction determined in uncoupled cells, suggesting the occurrence of another light-induced O 2-uptake process ( i.e. photorespiration). Rates of O2 exchange in uncoupled cells were half-saturated at 7% to 8% O2. Initial rates (during induction) of O2 exchange in uninhibited cells were also half-saturated at 7% to 8% O2. In contrast, steady-state rates of O2 evolution and O2 uptake (at low CO2) were half-saturated at 18% to 20% O2. O2 uptake was significantly suppressed in the presence of nitrate, suggesting that nitrate and/or nitrite can compete with O2 for photoreductant. These results suggest that two mechanisms (O2 reduction and photorespiration) are responsible for the light-dependent O2 uptake observed in uninhibited cells under CO2-limiting conditions. The relative contribution of each process to the rate of O2 uptake appears to be dependent on the O2 level. At high O2 concentrations (≥40%), photorespiration is the major O2-consuming process. At lower (ambient) O2 concentrations (≤20%), O2 reduction accounts for a significant portion of the total light-dependent O2 uptake. 相似文献
14.
Sunflower plants were grown under controlled environmental conditionswith either 0 or 10 mol m 3 phosphate (Pi). From steady-statemeasurements of gas exchange and chlorophyll fluorescence madeon intact leaves, the in vivo CO 2/O 2 specificity factor ( invivo Ksp) of ribulose 1,5-Aisphosphate carboxylase-oxygenase(Rubisco) was determined following two methods based on modelsof C 3 photosynthesis by Brooks and Farquhar (1985) and Peterson(1989). The two methods gave in vivo Ksp values for controlsunflower leaves which were similar to published values forhigher plants. Extreme Pi deficiency decreased in vivo Ksp,in sunflower leaves compared to adequate Pi. This suggests thatPi deficiency affected photorespiration less than photosynthesis.The decrease in in vivo Ksp may be due to a real change in theenzyme kinetics favouring oxygenation more than carboxylationor due to an increase in the number of CO 2 molecules releasedper oxygenation; in which case the observed decrease in the in vivo Ksp determined on intact leaves will not agree numericallywith the true K sp of Rubisco determined in vitro using purifiedenzyme from the same leaf. We discuss the implications of therelatively large photorespiration in Pi-deficient sunflowerleaves with respect to the increased dissipation of photosyntheticelectrons and photorespiratory recycling of Pi in thechloroplaststroma. Although our results on in vivo Ksp suggested a relativelylarger photorespiratory potential in Pi-deficient than controlsunflower leaves, photosynthesis was insensitive to O 2 in Pi-deficientleaves; the possible reasons for this phenomenon are discussed.Under extreme Pi deficiency, O 2 sensitivity of photosynthesisis not a reflection of the in vivo photorespiratory rates. Determinationof in vivo Ksp of Rubisco is a useful approach to study thephotorespiratory potential of intact leaves. Key words: Chlorophyll fluorescence, phosphate deficiency, photorespiration, photosynthesis, PSII quantum yield, Rubisco specificity factor 相似文献
15.
All measurements of photorespiration and gross photosynthesis in leaves, whether using isotopes or not, are underestimated because of the recycling of O 2 or CO 2. On the basis of a simple diffusion model, we propose a method for the calculation of the recycling and the corresponding underestimation of the measurements. This procedure can be applied when the stomatal resistance is known, and allows for a correction of certain results in the literature. It is found that measurements of the photorespiratory CO 2 release are usually underestimated by 20 to 100%, which sets the estimated rate of CO 2 photorespired at 30 to 50% of the net photosynthesis in C3 plants under normal conditions. In water stress studies, the correction of the photorespiration is still more important (1.5-3.3) because the stomata are closed more. Analysis of the diffusion of O 2 shows that its recycling is low and that the underestimation of photorespiration with 18O 2 is negligible. 相似文献
16.
Glycine decarboxylation, shown by us as an intermediate stepin CO 2 evolution during photorespiration, was enhanced by oxygentensions of up to 100%, whereas CO 2 evolution from glucose didnot increase when oxygen tensions were raised above 20%. Thus,we concluded that enhancement of photorespiration by oxygenis not only due to stimulation of glycolate oxidation, but alsoto stimulation of glycine decarboxylation.
1 This work was reported at the Annual Meeting (1971) of theJapanese Society of Plant Physiologists in Okayama.
2 The Okayama Tobacco Experiment Station, Japan Monopoly Corporation,Tamashima, Kurashiki, Okayama.
3 The Hatano Tobacco Experiment Station, Japan Monopoly Corporation,Naganuki, Hatano, Kanagawa. (Received October 19, 1971; ) 相似文献
17.
Incubation under water in a 30 C/14-hour or 12 C/10-hour photoperiod caused the CO 2 compensation points of 10 aquatic macrophytes to decrease below 25 or increase above 50 microliters CO 2 per liter, respectively. Submerged and aerial leaves of two amphibious angiosperms ( Myriophyllum brasiliense and Proserpinaca palustris) maintained high compensation points when incubated in air but, when the submerged or aerial leaves of Proserpinaca were incubated under water, the compensation points dropped as low as 10. This suggests that, in addition to temperature and photoperiod, some factor associated with submergence regulates the compensation point of aquatic plants. In the high-compensation point plants, photorespiration, as a percentage of net photosynthesis, was equivalent to that in terrestrial C 3 plants. For Hydrilla verticillata, the decreasing CO 2 compensation points (110, 40, and 10) were associated with reduced photorespiration, as indicated by decreased O 2 inhibition, decreased rates of CO 2 evolution into CO 2-free air, and increased net photosynthetic rates. 相似文献
18.
A normal appearing plant with a low rate of photorespiration (ratio of 14CO 2 released light/dark = 1.6) was found in an unselected tobacco ( Nicotiana tabacum) cultivar. The plant was self-pollinated, and further selections were made on several successive generations. Excised leaves from the progeny of the selections were examined for photorespiration and net CO 2 assimilation in normal air during photosynthesis. Similar measurements were made of plants derived from selfed parents with high rates of photorespiration (ratio of 14CO 2 released light/dark = 3.0 or greater). Efficient photosynthetic plants (greater than 22.0 mg of CO 2 dm −2 hr −1) with low rates of photorespiration produced a larger proportion of efficient progeny (about 25%) than did selfing inefficient plants (about 6%), but this proportion did not increase in successive generations. 相似文献
19.
The submersed angiosperms Myriophyllum spicatum L. and Hydrilla verticillata (L.f.) Royal exhibited different photosynthetic pulse-chase labeling patterns. In Hydrilla, over 50% of the 14C was initially in malate and aspartate, but the fate of the malate depended upon the photorespiratory state of the plant. In low photorespiration Hydrilla, malate label decreased rapidly during an unlabeled chase, whereas labeling of sucrose and starch increased. In contrast, for high photorespiration Hydrilla, malate labeling continued to increase during a 2-hour chase. Thus, malate formation occurs in both photorespiratory states, but reduced photorespiration results when this malate is utilized in the light. Unlike Hydrilla, in low photorespiration Myriophyllum, 14C incorporation was via the Calvin cycle, and less than 10% was in C 4 acids. Ethoxyzolamide, a carbonic anhydrase inhibitor and a repressor of the low photorespiratory state, increased the label in glycolate, glycine, and serine of Myriophyllum. Isonicotinic acid hydrazide increased glycine labeling of low photorespiration Myriophyllum from 14 to 25%, and from 12 to 48% with high photorespiration plants. Similar trends were observed with Hydrilla. Increasing O2 increased the per cent [14C]glycine and the O2 inhibition of photosynthesis in Myriophyllum. In low photorespiration Myriophyllum, glycine labeling and O2 inhibition of photosynthesis were independent of the CO2 level, but in high photorespiration plants the O2 inhibition was competitively decreased by CO2. Thus, in low but not high photorespiration plants, glycine labeling and O2 inhibition appeared to be uncoupled from the external [O2]/[CO2] ratio. These data indicate that the low photorespiratory states of Hydrilla and Myriophyllum are mediated by different mechanisms, the former being C4-like, while the latter resembles that of low CO2-grown algae. Both may require carbonic anhydrase to enhance the use of inorganic carbon for reducing photorespiration. 相似文献
20.
CO 2 exchange characteristics of detached mature and senescentflag leaves and of bracts in some Poaceae and Cyperaceae species,respectively, were studied using a closed IR system. Senescentleaves, 30 to 45 days after flowering, showed lower rates ofapparent photosynthesis and dark respiration, and higher CO 2compensation points (CCP) than those measured at the floweringstage. In senescent C 4-Poaceae, the increase of CCP was small(from 4.8 to 10.1 ppm on the average) with little influenceof temperature, and the photorespiration level, 0.4 mg CO 2/dm 2/hr,was as low as that in mature leaf, indicating the presence ofnormal C 4-characteristics. On the other hand, a C 4-Cyperaceae, Cyperus microria Steud., showed extensive increases of CCP (from9 to 41 ppm) and photorespiration (from 0.8 to 2.1 mg CO 2/dm 2/hr)with senescence. (Received August 25, 1979; ) 相似文献
|