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1.
Stomatal and non-stomatal limitations to photosynthesis in field-grown grapevine cultivars 总被引:1,自引:1,他引:0
Diurnal changes of photosynthesis in the leaves of grapevine (Vitis vinifera × V. labrusca) cultivars Campbell Early and Kyoho grown in the field were compared with respect to gas exchanges and actual quantum yield
of photosystem 2 (ΦPS2) in late May. Net photosynthetic rate (PN) of the two cultivars rapidly increased in the morning, saturated at photosynthetic photon flux density (PPFD) from 1200
to 1500 μmol m−2 s−1 between 10:00 and 12:00 and slowly decreased after midday. Maximum PN was 13.7 and 12.5 μmol m−2 s−1 in Campbell Early and Kyoho, respectively. The stomatal conductance (gs) and transpiration rate changed in parallel with PN, indicating that PN was greatly affected by gs. However, the decrease in PN after midday under saturating PPFD was also associated with the observed depression of ΦPS2 at high PPFD. The substantial increase in the leaf to air vapour pressure deficit after midday might also contribute to decline
of gs and PN. 相似文献
2.
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
3.
Photosynthetic Response of Carrots to Varying Irradiances 总被引:7,自引:3,他引:4
Response to irradiance of leaf net photosynthetic rates (P
N) of four carrot cultivars: Cascade, Caro Choice (CC), Oranza, and Red Core Chantenay (RCC) were examined in a controlled
environment. Gas exchange measurements were conducted at photosynthetic active radiation (PAR) from 100 to 1 000 μmol m−2 s−1 at 20 °C and 350 μmol (CO2) mol−1(air). The values of P
N were fitted to a rectangular hyperbolic nonlinear regression model. P
N for all cultivars increased similarly with increasing PAR but Cascade and Oranza generally had higher P
N than CC. None of the cultivars reached saturation at 1 000 μmol m−2 s−1. The predicted P
N at saturation (P
Nmax) for Cascade, CC, Oranza, and RCC were 19.78, 16.40, 19.79, and 18.11 μmol (CO2) m−2 s−1, respectively. The compensation irradiance (I
c) occurred at 54 μmol m−2 s−1 for Cascade, 36 μmol m−2 s−1 for CC, 45 μmol m−2 s−1 for Oranza, and 25 μmol m−2 s−1 for RCC. The quantum yield among the cultivars ranged between 0.057–0.033 mol(CO2) mol−1(PAR) and did not differ. Dark respiration varied from 2.66 μmol m−2 s−1 for Cascade to 0.85 μmol m−2 s−1 for RCC. As P
N increased with PAR, intercellular CO2 decreased in a non-linear manner. Increasing PAR increased stomatal conductance and transpiration rate to a peak between
600 and 800 μmol m−2 s−1 followed by a steep decline resulting in sharp increases in water use efficiency.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
4.
Z.-P. Ye 《Photosynthetica》2007,45(4):637-640
The calculated maximum net photosynthetic rate (P
N) at saturation irradiance (I
m) of 1 314.13 μmol m−2 s−1 was 25.49 μmol(CO2) m−2 s−1, and intrinsic quantum yield at zero irradiance was 0.103. The results fitted by nonrectangular hyperbolic model, rectangular
hyperbolic method, binomial regression method, and the new model were compared. The maximum P
N values calculated by nonrectangular hyperbolic model and rectangular hyperbolic model were higher than the measured values,
and the I
m calculated by nonrectangular hyperbolic model and rectangular hyperbolic model were less than measured values. Results fitted
by new model showed that the response curve of P
N to I was nonlinear at low I for Oryza sativa, P
N increased nonlinearly with I below saturation value. Above this value, P
N decreased nonlinearly with I. 相似文献
5.
Differences in photosynthetic apparatus of leaves from different sides of the chestnut canopy 总被引:1,自引:0,他引:1
In crowns of chestnut trees the absorption of radiant energy is not homogeneous; leaves from the south (S) side are the most
irradiated, but leaves from the east (E) and west (W) sides receive around 70 % and those from north (N) face less than 20
% of the S irradiation. Compared to the S leaves, those from the N side were 10 % smaller, their stomata density was 14 %
smaller, and their laminae were 21 % thinner. N leaves had 0.63 g(Chl) m−2, corresponding to 93 % of total chlorophyll (Chl) amount in leaves of S side. The ratios of Chl a/b were 2.9 and 3.1 and of Chl/carotenoids (Car) 5.2 and 4.8, respectively, in N and S leaves. Net photosynthetic rate (P
N) was 3.9 μmol(CO2) m−2 s−1 in S leaves, in the E, W, and N leaves 81, 77, and 38 % of that value, respectively. Morning time (10:00 h) was the period
of highest P
N in the whole crown, followed by 13:00 h (85 % of S) and 16:00 h with 59 %. Below 500 μmol m−2 s−1 of photosynthetic photon flux density (PPFD), N leaves produced the highest P
N, while at higher PPFD, the S leaves were most active. In addition, the fruits from S side were 10 % larger than those from
the N side. 相似文献
6.
Independent short-term effects of photosynthetic photon flux density (PPFD) of 50–400 μmol m−2 s−1, external CO2 concentration (C
a) of 85–850 cm3 m−3, and vapor pressure deficit (VPD) of 0.9–2.2 kPa on net photosynthetic rate (P
N), stomatal conductance (g
s), leaf internal CO2 concentration (C
i), and transpiration rates (E) were investigated in three cacao genotypes. In all these genotypes, increasing PPFD from 50 to 400 μmol m−2 s−1 increased P
N by about 50 %, but further increases in PPFD up to 1 500 μmol m−2 s−1 had no effect on P
N. Increasing C
a significantly increased P
N and C
i while g
s and E decreased more strongly than in most trees that have been studied. In all genotypes, increasing VPD reduced P
N, but the slight decrease in g
s and the slight increase in C
i with increasing VPD were non-significant. Increasing VPD significantly increased E and this may have caused the reduction in P
N. The unusually small response of g
s to VPD could limit the ability of cacao to grow where VPD is high. There were no significant differences in gas exchange
characteristics (g
s, C
i, E) among the three cacao genotypes under any measurement conditions. 相似文献
7.
Photosynthetic response of two shrubs to rainfall pulses in desert regions of northwestern China 总被引:1,自引:0,他引:1
Pulses of rainfall are particularly pivotal in controlling plant physiological processes in ecosystems controlled by limited
water, and the response of desert plants to rainfall is a key to understanding the responses of desert ecosystems to global
climatic change. We used a portable photosynthesis system to measure the responses of the diurnal course of photosynthesis,
light-response curves, and CO2-response curves of two desert shrubs (Nitraria sphaerocarpa Maxim. and Calligonum mongolicum Turcz) to a rainfall pulse in a desert-oasis ecotone in northwestern China. The photosynthetic parameters, light- and CO2-response curves differed significantly before and after the rainfall pulse. Their maximum net photosynthetic rate (P
N) values were 23.27 and 32.92 μmol(CO2) m−2 s−1 for N. sphaerocarpa and C. mongolicum, respectively, with corresponding maximum stomatal conductance (g
s) values of 0.47 and 0.39 mol(H2O) m−2 s−1. The P
N of N. sphaerocarpa after the rainfall was 1.65 to 1.75 times the value before rainfall, whereas those of C. mongolicum increased to approximately 2 times the prerainfall value, demonstrating the importance of the desert plants response by improving
their assimilation rate to precipitation patterns under a future climate. 相似文献
8.
Using CO2 gasometry, net photosynthetic (P
N) and dark respiration rates (R
D) were measured in leaves or traps of 12 terrestrial carnivorous plant species usually grown in the shade. Generally, mean
maximum P
N (60 nmol CO2 g−1(DM) s−1 or 2.7 μmol m−2 s−1) was low in comparison with that of vascular non-carnivorous plants but was slightly higher than that reported elsewhere
for carnivorous plants. After light saturation, the facultatively heliophytic plants behaved as shade-adapted plants. Mean
R
D in leaves and traps of all species reached about 50% of maximum P
N and represents the high photosynthetic (metabolic) cost of carnivory. 相似文献
9.
In order to assess the long-term impacts of saline groundwater irrigation to Haloxylon ammodendron, one of the main shrubs in the Tarim desert highway ecological shelterbelt, we irrigated the H. ammodendron seedlings with progressive saline groundwater (3–30 g L−1, simulation environment in the Tarim desert highway ecological shelterbelt) and investigated the diurnal variations of chlorophyll
a (Chl a) fluorescence parameters, such as maximal quantum yield of photosystem II (PSII) photochemistry (Fv/Fm), quantum yield of photochemical energy conversion in PSII (YII), the apparent rate of electron transport at the PSII level (ETR), photochemical quenching coefficient (qP), non-photochemical quenching (NPQ), quantum yield of nonregulated non-photochemical energy loss in PSII (YNO) and quantum yield of regulated non-photochemical energy loss in PSII (YII), at approximately 2-h intervals. Fv/Fm with 5 g L−1 (S2) was lower than that with 2 g L−1 (S1) but a little higher than 20 g L−1 (S5), respectively. Under the low light [photosyntheticallyactive radiation (PAR) ≤ 250 μmol m−2 s−1, at 08:00, 10:00 and 20:00 h of the local time], S1 kept the lowest YII and the highest YNPQ; while under the high light (PAR ≥ 1500 μmol m−2 s−1), the YII performed S1>S2>S5, and the reverse YNPQ; under mild light (250 μmol mt-2 s−1 ≤ PAR ≤ 1500 μmol m−2 s−1), S1 remained the highest YII, no matter the light and the salinity, the similar YNO almost occurred basically. The results showed that the sand-binding plant H. ammodendron could regulate its energy-utilizing strategies. The S2 might be the most suitable salinity of the irrigation water for H. ammodendron in the Tarim desert highway ecological shelterbelt in the northwest of China. 相似文献
10.
The model couples stomatal conductance (g
s) and net photosynthetic rate (P
N) describing not only part of the curve up to and including saturation irradiance (I
max), but also the range above the saturation irradiance. Maximum stomatal conductance (g
smax) and I
max can be calculated by the coupled model. For winter wheat (Triticum aestivum) the fitted results showed that maximum P
N (P
max) at 600 μmol mol−1 was more than at 350 μmol mol−1 under the same leaf temperature, which can not be explained by the stomatal closure at high CO2 concentration because g
smax at 600 μmol mol−1 was less than at 350 μmol mol−1. The irradiance-response curves for winter wheat had similar tendency, e.g. at 25 °C and 350 μmol mol−1 both P
N and g
s almost synchronously reached the maximum values at about 1 600 μmol m−2 s−1. At 25 °C and 600 μmol mol−1 the I
max corresponding to P
max and g
smax was 2 080 and 1 575 μmol m−2 s−1, respectively. 相似文献
11.
Diurnal and seasonal trends in net photosynthetic rate (P
N), stomatal conductance (g), transpiration rate (E), vapour pressure deficit, temperature, photosynthetic photon flux density, and water use efficiency (WUE) were compared
in a two-year-old Dalbergia sissoo and Hardwickia binata plantation. Mean daily maximum P
N in D. sissoo ranged from 21.40±2.60 μmol m−2 s−1 in rainy season I to 13.21±2.64 μmol m−2 s−1 in summer whereas in H. binata it was 20.04±1.20 μmol m−2 s−1 in summer and 13.64±0.16 μmol m−2 s−1 in winter. There was a linear relationship between daily maximum P
N and g
s in D. sissoo but there was no strong linear relationship between P
N and g
s in H. binata. In D. sissoo, the reduction in g
s led to a reduction in both P
N and E enabling the maintenance of WUE during dry season thereby managing unfavourable environmental conditions efficiently whereas
in H. binata, an increase in g
s causes an increase of P
N and E with a significant moderate WUE. 相似文献
12.
The relationship between net photosynthetic (P
N) and leaf respiration (R) rates of Quercus ilex, Phillyrea latifolia, Myrtus communis, Arbutus unedo, and Cistus incanus was monitored in the period February 2006 to February 2007. The species investigated had low R and P
N during winter, increasing from March to May, when mean air temperature reached 19.2 °C. During the favourable period, C. incanus and A. unedo had a higher mean P
N (16.4±2.4 μmol m−2 s−1) than P. latifolia, Q. ilex, and M. communis (10.0±1.3 μmol m−2 s−1). The highest R (1.89±0.30 μmol m−2 s−1, mean of the species), associated to a significant P
N decrease (62 % of the maximum, mean value of the species), was measured in July (mean R/P
N ratio 0.447±0.091). Q10, indicating the respiration sensitivity to short-term temperature increase, was in the range 1.49 to 2.21. Global change
might modify R/P
N determining differences in dry matter accumulation among the species, and Q. ilex and P. latifolia might be the most favoured species by their ability to maintain sufficiently higher P
N and lower R during stress periods. 相似文献
13.
Chlorophyll (Chl) content, dry mass, relative water content (RWC), leaf mass per area (LMA), proline (Pro) content, malondialdehyde
(MDA) content, superoxide dismutase (SOD) and peroxidase (POD) activity, P
N-PAR response curves and gas exchange were studied to determine the effects of water stress on photosynthetic activity, dry
mass partitioning and metabolic changes in four provenances of neem (Azadirachta indica A. Juss). The results indicated that provenance differences existed in the adaptation response to water stress that included
changes to growth strategies coupled with ecophysiological and metabolic adjustments. As water stress increased, stomatal
conductance (g
s), net photosynthetic rate (P
N), transpiration rate (E), and leaf RWC decreased while LMA increased in all provenances. Dry mass was reduced in droughted plants and the percentage
increased in dry mass allocated to roots, and enzyme activities of SOD and POD were highest in neem originating from Kalyani
(KA) provenance and lowest in neem originating from New Dehli (ND) provenance. In contrast, water stress increased MDA content
least in KA and most in ND. Furthermore, neem originating from ND also had the greatest decrease in Chl a/b ratio while the ratio was least affected in neem originating from KA. These findings suggest neem originating from KA may
have more drought resistance than neem originating from ND. The data from P
N-PAR response curves are less clear. While these curves showed that drought stress increased compensation irradiance (I
c) and dark respiration (R
D) and decreased saturation irradiance (I
s) and maximum net photosynthetic rate (P
max), the extent of decline in P
max was provenance dependent. P
max under non-waterlimiting conditions was higher in neem originating from Jodhpur (MA) (about 14 μmol m−2 s−1) than in the other three provenances (all about 10 μmol m−2 s−1), but mild water stress had minimal effect on P
max of these three provenances whereas P
max of MA provenance declined to 10 μmol m−2 s−1, i.e. a similar value. However, under severe water stress P
max of MA and KA provenances had declined to 40% of non-stressed values (about 6 and 4 μmol m−2 s−1, respectively) whereas the decline in P
max of neem originating from Kulapachta (KU) and ND provenances was about 50% of nonstressed values (about 5 μmol m−2 s−1). These data suggest the P
N responses of KU and ND provenances are most tolerant, and KA and MA least tolerant to increasing water stress, but also suggest
MA provenance could be the most desired under both non-water-limiting and water-limiting conditions due to highest P
max in all conditions. 相似文献
14.
We measured the diurnal changes in net photosynthetic rate (P
N) and stomatal conductance (g
s) of the leaves of a liana, Enkleia malaccensis Griff. (Thymelaeaceae), at the canopy level in the lowland tropical rainforest at Pasoh, Peninsular Malaysia. The measurements
were made from a canopy walkway system, 30 m from the ground for 3 d in March 2003. P
N increased with increasing photosynthetically active radiation (PAR) before noon, though P
N was not enhanced by the strong radiation hit in the afternoon. Plotting g
s at saturating PAR (>0.5 mmol m−2 s−1) against the vapour pressure deficit (VPD) failed to reveal a significant correlation between VPD and g
s, and g
s became very low at VPD >2.5 kPa. The relationship between P
N and g
s was fitted on the same regression line irrespective of measuring day, indicating that this relationship was not influenced
by either VPD or leaf temperature (T
L). Therefore, in the liana E. malaccensis, an increase in VPD leads to partial stomatal closure and, subsequently, reductions in P
N and the midday depression of P
N of this plant. 相似文献
15.
Genotypic variation in photosynthesis in cacao is correlated with stomatal conductance and leaf nitrogen 总被引:1,自引:0,他引:1
Variation in photosynthetic parameters was observed between eight contrasting cacao (Theobroma cacao) genotypes. Net photosynthetic rate (PN) ranged from 3.4 to 5.7 μmol(CO2) m−2 s−1 for the genotypes IMC 47 and SCA 6, respectively. Furthermore, genotypic differences were detected in quantum efficiency
ranging from 0.020 to 0.043 μmol(CO2) μmol−1(photon) for UF 676 and AMAZ 15/15, respectively. Differences in PN were correlated with both stomatal conductance (gs) and leaf nitrogen per unit area. Some variation in water use efficiency was observed between genotypes, both intrinsic (PN/gs) and instantaneous (PN/transpiration rate). Both measures of water use efficiency were a negative function of specific leaf area. Evidence was found
for a trade-off mechanism between cacao genotypes in photosynthesis and leaf structure. High photosynthetic rate, expressed
on a mass basis was associated with smaller leaves. Furthermore, thinner leaves were compensated for by a higher nitrogen
content per unit mass. 相似文献
16.
Photosynthetic parameters, growth, and pigment contents were determined during expansion of the fourth leaf of in vitro photoautotrophically cultured Nicotiana tabacum L. plants at three irradiances [photosynthetically active radiation (400–700 nm): low, LI 60 μmol m−2 s−1; middle, MI 180 μmol m−2 s−1; and high, HI 270 μmol m−2 s−1]. During leaf expansion, several symptoms usually accompanying leaf senescence appeared very early in HI and then in MI plants.
Symptoms of senescence in developing leaves were: decreasing chlorophyll (Chl) a+b content and Chl a/b ratio, decreasing both maximum (FV/FM) and actual (ΦPS2) photochemical efficiency of photosystem 2, and increasing non-photochemical quenching. Nevertheless, net photosynthetic
oxygen evolution rate (P
N) did not decrease consistently with decrease in Chl content, but exhibited a typical ontogenetic course with gradual increase.
P
N reached its maximum before full leaf expansion and then tended to decline. Thus excess irradiance during in vitro cultivation did not cause early start of leaf senescence, but impaired photosynthetic performance and Chl content in leaves
and changed their typical ontogenetic course. 相似文献
17.
Characteristics of net ecosystem carbon dioxide exchange (NEE) from August to October of Alpine meadow on the Tibetan Plateau, China 总被引:3,自引:0,他引:3
Xu Lingling Zhang Xianzhou Shi Peili Yu Guirui Sun Xiaomin 《Frontiers of Biology in China》2006,1(4):418-422
The Alpine meadow is one of the vegetation types widely distributed on the Tibetan Plateau in China with an area of about
1.2 million square kilometers. The Damxung rangeland station, located in the hinterland of the Tibetan Plateau, is covered
with an typical vegetation. The continuous carbon flux data (from August to middle October, 2003) measured with the open-path
eddy covariance system was used to analyze the diurnal variation pattern of net ecosystem carbon dioxide exchange (NEE) and
its relationship with the environmental factors, such as photosynthetically active radiation (PAR), precipitation, and temperature.
Results showed that NEE presented obvious diurnal variation pattern with single-peak of diurnal maximum carbon assimilation
at 11: 00–12: 00 (local time) with an average of −0.268 mg CO2·m−2·s−1, i.e., −6.08 μmol CO2·m−2·s−1. During the daytime, NEE fitted fairly well with PAR in a rectangular hyperbola function with the apparent quantum yield
(0.020 3 μmol CO2 μmol−1 PAR) and maximum ecosystem assimilation (9.741 1 μmol CO2·m−2·s−1). During the night-time, NEE showed a good exponential relation with the soil temperature at 5 cm depth.
__________
Translated from Acta Ecologica Sinica 2005, 25(8): 1948–1952 [译自: 生态学报, 2005, 25(8): 1948–1952] 相似文献
18.
I. E. Papadakis A. Giannakoula C. P. Antonopoulou M. Moustakas E. Avramaki I. N. Therios 《Photosynthetica》2007,45(2):208-213
Citrus volkameriana (L.) plants were grown for 43 d in nutrient solutions containing 0, 2, 14, 98, or 686 μM Mn (Mn0, Mn2, Mn14, Mn98, and Mn686, respectively). To adequately investigate the combined effects of Mn nutrition and irradiance on photosystem 2 (PS2) activity,
irradiance response curves for electron transport rate (ETR), nonphotochemical quenching (qN), photochemical quenching (qP), and real photochemical efficiency of PS2 (ΦPS2) were recorded under 10 different irradiances (66, 96, 136, 226, 336, 536, 811, 1 211, 1 911, and 3 111 μmol m−2 s−1, I66 to I3111, respectively) generated with the PAM-2000 fluorometer. Leaf chlorophyll content was significantly lower under Mn excess (Mn686) compared to Mn0; its highest values were recorded in the treatments Mn2-Mn98. However, ETR and ΦPS2 values were significantly lower under Mn0 compared to the other Mn treatments, when plants were exposed to irradiances ≥96 μmol m−2 s−1. Furthermore, Mn0 plants had significantly higher values of qN and lower values of qP at irradiances ≤226 and ≥336 μmol m−2 s−1, respectively, than those grown under Mn2-Mn686. Irrespective of Mn treatment, the values of ΦPS2 and qN decreased, while those of qP increased progressively by increasing irradiance from I136 to I3111. Finally, Mn2-Mn98 plants were less sensitive to photoinhibition of photosynthesis (≥811 μmol m−2 s−1) than the Mn686 (≥536 μmol m−2 s−1) and Mn0 (≥336 μmol m−2 s−1) ones. 相似文献
19.
In an experimental site for reforestation of degraded area, three-year-old plants of Bertholletia excelsa Humb. & Bonpl. were subjected to different fertilization treatments: T0 = unfertilized control, T1 = green fertilization
(branches and leaves) and T2 = chemical fertilization. Higher net photosynthetic rates (P
N) were observed in T1 [13.2±1.0 μmol(CO2) m−2 s−1] compared to T2 [8.0±1.8 μmol(CO2) m−2 s−1] and T0 [4.8±1.3 μmol(CO2) m−2 s−1]. Stomatal conductance (g
s), transpiration rate (E) and water use efficiency (WUE) of individuals of T1 and T2 did not differ significantly, however, they were by 88, 55 and
63%, respectively, higher in T1 than in the control. The mean values of variable fluorescence (Fv), performance index (P.I.) and total chlorophyll [Chl (a+b)] were higher in T1. Our results indicate that green fertilization improves photosynthetic structure and function in plants
of B. excelsa in young phase. 相似文献
20.
The relationships between dark respiration rate (R
D) and net photosynthetic rate (P
N) in Quercus ilex L. shrubs growing at the Botanical Garden in Rome were analysed. Correlation analysis of the data sets collected in the year
2006 confirmed the dependence among the considered leaf traits, in particular, R
D was significantly (p<0.05) correlated with P
N (r = 0.40). R
D and P
N increased from March to May [1.40±0.10 and 10.1±1.8 μmol(CO2) m−2 s−1 mean values of the period, respectively], when air temperature was in the range 14.8–25.2 °C, underlining the highest metabolic
activity in the period of the maximum vegetative activity that favoured biomass accumulation. On the contrary, the highest
R
D [1.60±0.02 μmol(CO2) m−2 s−1], associated to the lowest P
N rates (44 % of the maximum) and carbon use efficiency (CUE) in July underlined the mobilization of stored material during
drought stress by a higher air temperature (32.7 °C). 相似文献