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1.
Growth and Leaf Gas Exchange Characteristics in Dalbergia sissoo Roxb. and D. latifolia Roxb. Under Water Deficit 总被引:1,自引:0,他引:1
Forty two-month-old plants of Dalbergia sissoo and D. latifolia were subjected for 56 d to water deficit induced by withholding water. Drought stress caused a significant reduction in plant height, stem diameter, net photosynthetic rate (P
N), transpiration rate (E), and stomatal conductance (g
s) in both species, but the reduction was greater in D. sissoo than in D. latifolia. Water use efficiency (P
N/E) was adversely affected due to water stress only in D. latifolia, and intrinsic water use efficiency (P
N/g
s) was increased in both species. There was a slight effect of water stress on variable to maximum fluorescence (Fv/Fm) (quantum yield of photosystem 2) in both species, but the species did not differ significantly in this attribute. 相似文献
2.
Photosynthesis and growth characteristics of Parthenocissus quinquefolia were measured under differing soil water availability within a pot. Decreased soil moisture significantly reduced the leaf relative water content (RWC) and the above- and below-ground biomass. However, more biomass was allocated to the root than to the leaf. Net photosynthetic rate (P
N), stomatal conductance (g
s), and transpiration rate (E) were also significantly decreased but water use efficiency (WUE) was increased. Midday depressions in P
N and g
s were not evident for the well-irrigated plants. With the lower water availability, midday reductions in P
N and g
s were much more marked and the duration of the depression was longer. Additionally, the P
N-irradiance response curves also indicated that water supply affected photosynthesis capacity. The growth and photosynthetic response of P. quinquefolia to water supply indicated that this species could resilient to water availabilities and adapt to Hunshandak conditions very well. 相似文献
3.
Net photosynthetic rate (P
N), transpiration rate (E), stomatal conductance (g
s), and leaf water potential (Ψl) of an annual pioneer C4 grass (Agriophyllum squarrosum) were compared under different simulated precipitation events in a field of Hunshandak Sandland, China. The increase of soil
water content (SWC) had significant effect on these physiological traits (p<0.001). In the vegetative stage, the values of P
N, E, and g
s went up sharply when SWC increased at the beginning, while they went down with continuous increase of SWC. P
N, E, and g
s increased 1.4, 1.7, and 1.7 fold, respectively, with SWC range from 6.7 to 11.6 %. In the reproductive stage, similar trends
were found, except for the climate with a higher SWC. This indicated that A. squarrosum was very sensitive to the small increment of SWC which might have a large photosynthetic potential. Ψl increased by about 8 % as the SWC changed from 6.7 to 8.8 %, and then maintained a steady level when the SWC was higher than
8.8 %, while the values of P
N, E, and g
s kept increasing even after this SWC. This might indicate that the adjustment of Ψl response to the changes of SWC lagged that of the photosynthetic parameters.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
4.
K. Palanisamy 《Photosynthetica》1999,36(4):635-638
Response of net photosynthetic rate (P
N), stomatal conductance (g
s), intercellular CO2 concentration (c
i), and photosynthetic efficiency (Fv/Fm) of photosystem 2 (PS2) was assessed in Eucalyptus cladocalyx grown for long duration at 800 (C800) or 380 (C380) μmol mol-1 CO2 concentration under sufficient water supply or under water stress. The well-watered plants at C800 showed a 2.2 fold enhancement of P
N without any change in g
s. Under both C800 and C380, water stress decreased P
N and g
s significantly without any substantial reduction of c
i, suggesting that both stomatal and non-stomatal factors regulated P
N. However, the photosynthetic efficiency of PS2 was not altered.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
5.
6.
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
7.
H. X. Cui G. M. Jiang S. L. Niu Y. G. Li C. D. Jiang M. Z. Liu L. M. Gao 《Photosynthetica》2004,42(4):529-534
Net photosynthetic rate (P
N), transpiration rate (E), water use efficiency (WUE), stomatal conductance (g
s), and stomatal limitation (Ls) were investigated in two Syringa species. The saturation irradiance (SI) was 400 µmol m-2s-1 for S. pinnatifolia and 1 700 µmol m-2s-1 for S. oblata. Compared with S. oblata, S. pinnatifolia had extremely low gs. Unlike S. oblata, the maximal photosynthetic rate (P
max) in S. pinnatifoliaoccurred around 08:00 and then fell down, indicating this species was sensitive to higher temperature and high photosynthetic photon flux density. However, such phenomenon was interrupted by the leaf development rhythms before summer. A relatively lower P
N together with a lower leaf area and shoot growth showed the capacity for carbon assimilation was poorer in S. pinnatifolia.This revised version was published online in March 2005 with corrections to the page numbers. 相似文献
8.
Influence of manganese (Mn) toxicity on photosynthesis in ricebean (Vigna umbellata) was studied by the measurement of gas exchange characteristics and chlorophyll fluorescence parameters. The net photosynthetic
rate (P
N), transpiration rate (E), and stomatal conductance (g
s) were reduced with increasing Mn concentration in nutrient solution. The reduction in g
s and E was more pronounced at 6 d of Mn treatment. However, P
N declined at 2 d of Mn treatment implying that the reduction in photosynthesis was not due to the direct effect of Mn on stomatal
regulation. Mn did not affect the maximum efficiency of photosystem 2 (PS2) photochemistry (Fv/Fm). A reduction in photochemical quenching (qP) and excitation capture efficiency of open PS2 (Fv′/Fm′) with a concomitant increase in qN was observed. This implies that reduced demand for ATP and NADPH due to the reduction in photosynthesis causes a down-regulation
of PS2 photochemistry and thus a high pH gradient (increase in qN) and limited electron transport (decreased qP).
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
9.
Net photosynthetic rate (PN), transpiration rate (E), and stomatal conductance (gs) during water stress and after rehydration were measured in Phaseolus vulgaris, Beta vulgaris, and Zea mays. Immediately before imposition of water stress by cessation of watering, plants were irrigated with water (control), 100 M abscisic acid (ABA), and/or 10 M N6-benzyladenine (BA). In all three species, application of ABA decreased gs, E, and PN already 1 h after application. However, during water stress gs, E, and PN in plants pre-treated with ABA remained higher than in plants pre-treated with water. Positive effects of ABA application were observed also after rehydration. In contrast, the effects of pre-treatment with BA were species-specific. While in bean plants BA application ameliorated negative effect of water stress, only very slight effects were observed in maize, and in sugar beet BA even aggravated the effects of water stress. 相似文献
10.
Net photosynthetic rate (P
N), transpiration rate (E), and stomatal conductance (g
s) declined from upper leaves to the lower ones during dry and rainy seasons, indicating that long-term carbon budget should take into account P
N variations for different leaf types. Relatively greater P
N in the dry season suggested that this species is more able to maintain higher P
N under drought, but the relatively higher E in the dry season might reduce water use efficiency (P
N/E) for the species. Significant correlations between P
N and g
s indicated that g
s may be the critical factor for P
N variability in the desert region. 相似文献
11.
The possibility to improve the recovery of sugar beet plants after water stress by application of synthetic cytokinins N6-benzyladenine (BA) or N6-(m-hydroxybenzyl)adenosine (HBA) was tested. Relative water content (RWC), net photosynthetic rate (PN), transpiration rate (E), stomatal conductance (gs), chlorophyll (Chl) a and Chl b contents, and photosystem 2 efficiency characterized by variable to maximal fluorescence ratio (Fv/Fm) were measured in control plants, in water-stressed plants, and after rehydration (4, 8, 24, and 48 h). Water stress markedly decreased parameters of gas exchange, but they started to recover soon after irrigation. Application of BA or HBA to the substrate or sprayed on leaves only slightly stimulated recovery of PN, E, and gs in rehydrated plants, especially during the first phases of recovery. Chl contents decreased only under severe water stress and Fv/Fm ratio was not significantly affected by water stress applied. Positive effects of BA or HBA application on Chl content and Fv/Fm ratio were mostly not observed. 相似文献
12.
Peanut Photosynthesis Under Drought and Re-Watering 总被引:2,自引:0,他引:2
The photosynthetic response of three Arachis hypogaea L. cultivars (57-422, 73-30, and GC 8-35) grown for two months was measured under water available conditions, severe water stress, and 24, 72, and 93 h following re-watering. At the end of the drying cycle, all the cultivars reached dehydration, relative water content (RWC) ranging between 40 and 50 %. During dehydration, leaf stomatal conductance (g
s), transpiration rate (E), and net photosynthetic rate (P
N) decreased more in cvs. 57-422 and GC 8-35 than in 73-30. Instantaneous water use efficiency (WUEi) and photosynthetic capacity (P
max) decreased mostly in cv. GC 8-35. Except in cv. GC 8-35, the activity of photosystem 1 (PS1) was only slightly affected. PS2 and ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO) were the main targets of water stress. After re-watering, cvs. 73-30 and GC 8-35 rapidly regained g
s, E, and P
N activities. Twenty-four hours after re-watering, the electron transport rates and RuBPCO activity strongly increased. P
N and P
max fully recovered later. Considering the different photosynthetic responses of the studied genotype, a general characterisation of the interaction between water stress and this metabolism is presented. 相似文献
13.
Tolerance to Water Stress in Tomato Cultivars 总被引:2,自引:0,他引:2
The effects of plant water stress imposed at vegetative, flowering, and fruiting stages of four cultivars of tomato (Lycopersicon esculentum Mill.) on net photosynthetic rate (P
N), stomatal conductance (g
s), transpiration rate (E), osmotic adjustment, and crop water stress index (CWSI) were investigated. Osmotic adjustment was the highest in cv. Arka
Meghali, followed by cv. RFS-1. CWSI was lowest in cv. Arka Meghali and highest in cv. Pusa Ruby. Significant reduction in
g
s, E, and P
N was observed in all the cultivars. The maximum reduction in E was observed in cv. Arka Saurabh during the fruiting stage (62.4 %) and maximum reduction in P
N at the flowering stage in Pusa Ruby (53.1 %). Maximum P
N was observed in Arka Meghali under water stress. The values of internal CO2 concentration (C
i) did not follow the decrease in g
s which might be taken as an indication of mesophyll (non-stomatal) limitation to P
N. Magnitude of P
N decrease accompanying g
s reductions varied in the four cultivars. Arka Meghali which had highest rate of gas exchange efficiency (P
N/g
s) under water deficits can be recommended for rainfed cultivation.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
14.
T. Łoboda 《Photosynthetica》2001,38(3):429-432
During mild water stress (decrease of full water capacity from 60 to 35 %) net photosynthetic rate (P
N) of four spring barley and wheat genotypes was about twice lower than that for unstressed plants and was mainly limited by
non-stomatal factors. Availability of CO2 from intercellular spaces did not change significantly when stomatal conductance (g
s) decreased from 0.25-0.35 to 0.15-0.20 mol(H2O) m−2 s−1. There may be two main processes leading to similar intercellular CO2 concentration (c
i) in stressed and unstressed seedlings despite of twice lower P
N under mild water stress: (a) lower diffusion of CO2 through stomata represented by lower g
s, (b) lower consumption of CO2 by photosynthetic apparatus of stressed plants. Last factor is partially pronounced by lower response of P
N to c
i observed for stressed than for control plants.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
15.
Gas Exchange and Chlorophyll Fluorescence in Symbiotic and Non-Symbiotic Ryegrass Under Water Stress 总被引:10,自引:0,他引:10
The symbiotic association of endophyte fungus, Neotyphodium lolii, and ryegrass improves the ryegrass resistance to drought. This is shown by a 30 % increase in the number of suckers in infected
plants (E+), compared to plants lacking endophyte (E−), and by a higher water potential in the E+ than E− plants. The E+ plants
have higher stomatal conductance (g
s), transpiration rate, net photosynthetic rate (P
N), and photorespiratory electron transport rate than the E− plants. The maximal photochemical efficiency (Fv/Fm) and the actual photochemical efficiency (ΦPS2) are not affected by the endophyte fungus. The increase in P
N of the E+ plants subjected to water stress was independent from internal CO2 concentration. An increased P
N was observed in E+ plants also in optimal water supply. Hence the drought resistance of E+ plants results in increased g
s, P
N, and photorespiratory electron transport rate.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
16.
Under greenhouse conditions, seedlings of three forest species, baldcypress (Taxodium distichum), nuttall oak (Quercus nuttallii), and swamp chestnut oak (Quercus michauxii) were subjected to an intermittent flooding and subsequent physiological and growth responses to such conditions were evaluated. Baldcypress showed no significant reductions in stomatal conductance (g
s) or net photosynthetic rate (P
N) in response to flood pulses. In nuttall oak seedlings g
s and P
N were significantly decreased during periods of inundation, but recovered rapidly following drainage. In contrast, in swamp chestnut oak g
s was reduced by 71.8 % while P
N was reduced by 57.2 % compared to controls. Baldcypress displayed no significant changes in total mass while oak species had significantly lower leaf and total mass compared to their respective controls. Thus baldcypress and nuttall oak showed superior performance under frequent intermittent flooding regimes due to several factors including the ability for rapid recovery of gas exchange soon after soil was drained. In contrast, swamp chestnut oak seedlings failed to resume gas exchange functions after the removal of flooding. 相似文献
17.
Photosynthetic and stomatal responses of two tropical and two temperate trees to atmospheric humidity 总被引:4,自引:0,他引:4
The effects of leaf to air vapour pressure differences (ΔW) on net photosynthetic rate (PN) and stomatal conductance (gs) were examined in the leaves of two tropical rain forest trees, Eugenia grandis and Pongamia pinnata, and two temperate evergreen
trees, Viburnum awabuki and Daphniphyllum macropodum. A single leaf was set inside a small chamber and ΔW was varied from
7 to 24 mmol mol-1 at 25 and 500 μmol m-2 s-1 of photon flux density. PN and gs of the two tropical rain forest trees decreased with increasing ΔW, while the two temperate evergreen trees were not highly
responsive to ΔW. P. pinnata was more sensitive to ΔW in its stomatal response, and had a higher stomatal density and higher
stomatal index than did the two temperate trees and another tropical tree. Significant reductions i n gs and intercellular CO2 concentrations in the two tropical trees at high ΔW suggest that the decline of PN was due to the decrease in gs. The responses of PN and gs indicated that the tropical trees were more sensitive to ΔW than were the temperate ones.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
18.
Cadmium (Cd) treatments caused an inhibition in the net photosynthetic rate (P
N) of peanut (Arachis hypogaea) plants, due to the reduction of stomatal conductance (g
s) and photosynthetic pigment contents, as well as the alteration in leaf structure. The decrease of the transpiration rate
and g
s might result from the Cd-induced xerophyte anatomic features of leaves (i.e. thick lamina, upper epidermis, palisade mesophyll, high palisade to spongy thickness ratio, as well as abundant and small
stomata). The decline of P
N was independent of the impairment in photosystem 2. 相似文献
19.
Leaf Gas Exchange and Water Relations of Grapevines Grown in Three Different Conditions 总被引:2,自引:1,他引:1
Moutinho-Pereira J.M. Correia C.M. Gonçalves B.M. Bacelar E.A. Torres-Pereira J.M. 《Photosynthetica》2004,42(1):81-86
Diurnal and seasonal changes in the leaf water potential (), stomatal conductance (g
s), net CO2 assimilation rate (P
N), transpiration rate (E), internal CO2 concentration (C
i), and intrinsic water use efficiency (P
N/g
s) were studied in grapevines (Vitis vinifera L. cv. Touriga Nacional) growing in low, moderate, and severe summer stress at Vila Real (VR), Pinhão (PI), and Almendra (AL) experimental sites, respectively. In VR and PI site the limitation to photosynthesis was caused more by stomatal limitations, while in AL mesophyll limitations were also responsible for the summer decline in P
N. 相似文献
20.
Thirty-days-old plants of two cultivars of okra (Hibiscus esculentus L.), Sabzpari and Chinese-red, were subjected for 30 d to two water regimes (100 and 60 % field capacity). Leaf water potential and osmotic potential of both lines decreased significantly with the imposition of drought. Both the leaf pressure potential and osmotic adjustment were much lower in Chinese-red than those in Sabzpari. Chlorophyll (Chl) b content increased, whereas Chl a content remained unchanged and thus Chl a/b ratios were reduced in both lines. Drought stress also caused a significant reduction in net photosynthetic rate (P
N), transpiration rate (E), stomatal conductance (g
s), and water use efficiency (WUE) especially in cv. Sabzpari. The lines did not differ in intrinsic WUE (P
Ngs) or intercellular/ambient CO2 ratio. Overall, the growth of two okra cultivars was positively correlated with P
N, but not with g
s or P
N/E, and negatively correlated with osmotic adjustment. 相似文献