共查询到20条相似文献,搜索用时 31 毫秒
1.
The possibility of improving the recovery of plant photosynthesis after water stress by cytokinin-induced stimulation of stomatal opening or delay of leaf senescence was tested. The 6-benzylaminopurine (BAP) in concentrations 1 and 10 M was applied to the substrate (sand + nutrient solution) or sprayed on primary leaves of 14-d-old Phaseolus vulgaris L. plants sufficiently supplied with water or water-stressed for 4 d. The later ones having relative water content decreased to 69 % were fully rehydrated during the following three days. Parameters of photosynthesis and water relations were measured in primary leaves of 7-, 10-, 14-, and 17-d-old plants. Application of 1 M BAP slightly delayed leaf senescence: in 17-d-old control plants, net photosynthetic rate (PN) and chlorophyll (Chl) content, and when sprayed on leaves also some of Chl a fluorescence kinetic parameters of BAP-treated leaves were slightly higher than those of untreated leaves. Both types of application of 1 M BAP slightly improved recovery of plants during rehydration after water stress in terms of increased gad, gab and PN, i.e., parameters which were markedly decreased by mild water stress. However, contents of Chl a, Chl b and carotenoids and parameters of Chl a fluorescence kinetic were not markedly affected by mild water stress and after rehydration were not stimulated by 1 M BAP. 10 M BAP had mostly negative effects on the parameters measured. 相似文献
2.
The effect of Potato virus Y NTN (PVY) infection upon photosynthesis was analysed in transgenic Pssu-ipt tobacco overproducing endogenous cytokinins in comparison with control, nontransgenic Nicotiana tabacum plants. The course of the infection from the early to the late stage was monitored by measuring of photosynthetic gas exchange and fast chlorophyll (Chl) a fluorescence induction kinetics. Leaf photosynthesis was also analysed using Chl fluorescence imaging (Chl-FI). From the different fluorescence parameters obtained using Chl-FI, the nonphotochemical quenching (NPQ) proved to be the most useful parameter to assess the effect of PVY infection. On the other hand, Chl-FI was found to be inapplicable for any presymptomatic detection of PVY infection in tobacco. The lower accumulation of the virus was found in transgenic plants and corresponded also with the presence of visible symptoms of PVY infection. The net photosynthetic rate (P N), transpiration rate (E), and stomatal conductance (g s) significantly decreased with the progress of the infection in both control plant types and transgenic rooted plants, while transgenic grafts were much less affected. The analysis of the Chl fluorescence transient revealed higher number of silent dissipative reaction centres, higher nonphotochemical dissipation, and significantly lower performance index, PI(abs), in the healthy transgenic grafts. Chl-FI also confirmed significantly higher NPQ in transgenic grafts. 相似文献
3.
Pospíšilová Jana Haisel Daniel Synková Helena Čatský Jiří Wilhelmová Nad'a Plzáková Šárka Procházková Dagmar Šrámek František 《Plant Cell, Tissue and Organ Culture》2000,62(2):125-133
Nicotiana tabacum L. plantlets were grown in glass vessels or in Magenta boxes with better CO2 supply. To improve the ex vitro transfer we tested application of abscisic acid and elevated CO2 concentration. In the first two weeks after transfer, net photosynthetic rate, chlorophyll a+b content, and Chl a/b ratio were higher, and content of xanthophyll cycle pigments lower in M-plants than in G-plants, but during further growth
the differences almost disappeared. ABA application alleviated the risk of wilting because it decreased stomatal conductance.
The effect of ABA was enhanced under CE (28 days after transfer). In situ, PN was always higher at CE than at CA, but when measured under CA, positive effect of CE was found 2 and 16 days after transfer
in M-plants and only 16 days after transfer in G-plants. Slightly increased Chl a content was found in all ABA-treated plants, and in M-plants grown under CE. The content of xanthophyll cycle pigments was
lower under CE compared to CA, and the lowest one was found in ABA-treated M-plants grown under CE. On the contrary, the degree
of their deepoxidation (DEPS) was slightly higher in plants grown under CE. No significant effects of ABA-treatment or growth
under CE on fluorescence kinetic parameters were found and inconsistent effects on photochemical activities. The photochemical
efficiency of PS2 (variable to maximum fluorescence ratio, Fv/Fm) after ex vitro transfer was similar to that in in vitro grown plants. This together with the values of DEPS indicated that no photodamage during ex vitro transfer occurred.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
4.
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
5.
The responses of tobacco plants over-expressing trans-zeatin O-glucosyltransferase gene under constitutive or senescence-inducible promoter (35S:ZOG1 and SAG12:ZOG1) and of wild type (WT) plants to water stress and subsequent rehydration were compared. In plants sufficiently supplied with
water, both transgenics have higher net photosynthetic rate (PN) in upper and middle leaves and higher stomatal conductance (gs) in middle leaves than WT. Water use efficiency (WUE = PN/E) was higher in both transgenics than in WT. During prolonged water stress, both PN and E declined to a similar extent in both transgenics and WT plants. However, 7 d after rehydration PN in SAG:ZOG (upper and middle leaves) and 35S:ZOG (upper leaves) was higher than that in WT plants. Increased content of endogenous CKs in 35S:ZOG plants did not prevent their response to ABA application and the results obtained did not support concept of CK antagonism
of ABA-induced stomatal closure. The chlorophyll (Chl) a+b content was mostly higher in both transgenics than in WT. During water stress and subsequent rehydration it remained unchanged
in upper leaves, decreased slightly in middle leaves only of WT, while rapidly in lower leaves. Total degradation of Chl,
carotenoids and xanthophyll cycle pigments (XCP) was found under severe water stress in lower leaves. Carotenoid and XCP contents
in middle and upper leaves mostly increased during development of water stress and decreased after rehydration. While β-carotene
content was mostly higher in WT, neoxanthin content was higher in transgenics especially in 35S:ZOG under severe stress and after rehydration. The higher content of XCP and degree of their deepoxidation were usually found
in upper and middle leaves than in lower leaves with exception of SAG:ZOG plants during mild water stress. 相似文献
6.
The content of cytokinins (CKs), the plant inhibitors of the final phase of plant development, senescence, is effectively
controlled by irreversible degradation catalysed by cytokinin oxidase/dehydrogenase (CKX). In transgenic tobacco, denoted
as AtCKX, with over-expressed CKX causing lowered CK content, we investigated changes in the time courses of chlorophyll (Chl)
and xanthophyll (violaxanthin, antheraxanthin, zeaxanthin, neoxanthin, and lutein) contents. We also determined parameters
of slow Chl fluorescence kinetics such as minimum Chl fluorescence yield in the darkadapted state F0, maximum quantum yield of PS2 photochemistry (Fv/Fm), maximum ratio of quantum yields of photochemical and concurrent non-photochemical processes in photosystem 2 (PS2), Fv/F0, non-photochemical quenching (NPQ), and effective quantum yield of photochemical energy conversion in PS2 (Φ2). We used three different developmental leaf stages, old, mature, and young, and compared this with time courses of these
characteristics in leaves with natural CK levels. The parameters Fv/Fm, Fv/F0, and Φ2 were unchanged during ageing in AtCKX plants in contrast to control ones where a significant decrease in old leaves was found.
In control plants F0 increased during ageing, but in the oldest leaf a considerable decrease was observed. This could indicate progressive damage
to PS2 reaction centres and then detachment and rapid degradation of Chl. This is in agreement with time course of Chl content.
NPQ decreased with age and was similar in both plant types. We observed a decline of xanthophyll contents in the oldest leaves
in both plant types, but the contents were enhanced in AtCKX compared to control plants, especially of neoxanthin. The higher
xanthophyll contents in the transgenic plants contribute to a better photoprotection and the fluorescence parameters indicated
that photosynthetic apparatus was in better condition compared to control and it consequently postponed the onset of leaf
senescence. 相似文献
7.
Plant growth, chlorophyll (Chl) content, photosynthetic gas exchange, ribulose-1,5-bisphosphate carboxylase (RuBPCO) enzyme
activity, and Chl fluorescence in radish (Raphanus sativus var. longipinnatus) plants were examined after turnip mosaic virus (TuMV) infection. Plant fresh mass, dry mass, Chl content, net photosynthetic
rate (P
N), transpiration rate (E), stomatal conductance (g
s), and RuBPCO activity were significantly lower in infected plants after 5 weeks of virus infection as compared to healthy
plants. The 5-week virus infection did not induce significant differences in intercellular CO2 concentration (C
i, photochemical efficiency of photosystem 2, PS2 (Fv/Fm), excitation capture efficiency of open PS2 reaction centres (Fv'/Fm'), effective quantum efficiency of photosystem 2 (ΔF/Fm'), and photochemical quenching (qP), but non-photochemical quenching (qN) and alternative electron sink (AES) were significantly enhanced. Thus the decreased plant biomass of TuMV-infected plants
might be associated with the decreased photosynthetic activity mainly due to reduced RuBPCO activity. 相似文献
8.
D. Haisel J. Pospíšilova H. Synková J. Čatský N. Wilhelmová Š. Plzáková 《Biologia Plantarum》1999,42(3):463-468
Contents and functioning of photosynthetic pigments and gas exchange of Nicotiana tabacum L. leaves were studied in platlets
cultivated in vitro under different CO2 supply. The plantlets were grown for six weeks either in glass vessels tightly closed with aluminium foil (G-plants) or in
polycarbonate Magenta GA-7 vessels covered with closures with microporous vents (M-plants). M-plants (better supplied with
CO2) had higher contents of chlorophyll (Chl) a. Chl b. and β-carotene, higher photochemical activities of photosystem 2 and
whole electron transport chain, and lower contents of xanthophyll cycle pigments. Differences in Chl a fluorescence kinetic
parameters between G-plants and M-plants were not statistically significant. M-plants had higher net photosynthetic rate,
and lower transpiration rate and stomatal conductance than G-plants.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
9.
Photochemical efficiency, photosynthetic capacity, osmoprotectants, and relative water content (RWC) were recorded in saplings
of two evergreen plants (Boehmeria rugulosa Wedd. and Olea glandulifera Wall. ex G. Don) grown inside (GL) and outside (OP) a glasshouse during the winter season. The OP plants experienced 2.0–2.5 °C lower
air temperature and dew formation in comparison to GL plants. Diurnal observations indicated no change in RWC in the leaves
of GL and OP plants, while significant reduction in both transpiration and net photosynthetic (P
N) rates was observed in OP plants: the reduction in P
N was much more prominent as was also reflected by poor water use efficiency of these plants. Similarly, OP plants also showed
decrease in the apparent quantum yield and irradiance-saturated CO2 assimilation rate. The decrease in P
N was not associated with decreased stomatal conductance. However, a significant reduction in the ratio of variable to maximum
chlorophyll (Chl) fluorescence (Fv/Fm) and Chl content was recorded in the OP plants which also contained more total soluble saccharides but less proline contents.
The greater enhancement of P
N at 15 °C in comparison to measurements taken at 10 °C in OP plants over GL plants probably indicated an increase in mesophyll
capacity of the OP plants’ growth at increased temperature. Hence the enhanced growth and productivity of plants grown in
sheltered environments could be associated to their higher photosynthetic activity that may have important bearing on their
field establishment and productivity in the long run. The response varied with plant species; reduction in P
N was greater in B. rugulosa than in O. glandulifera. However, the recovery of OP plants in terms of Fv/Fm in the subsequent months revealed that photosynthetic system of these plants is revocable. 相似文献
10.
Diurnal patterns of gas exchange and chlorophyll (Chl) fluorescence parameters of photosystem 2 (PS2) as well as Chl content
were analyzed in Reaumuria soongorica (Pall.) Maxim., a perennial semi-shrub during dehydration and rehydration. The net photosynthetic rate (P
N), maximum photochemical efficiency of PS2 (variable to maximum fluorescence ratio, Fv/Fm), quantum efficiency of non-cyclic electron transport of PS2, and Chl content decreased, but non-photochemical quenching
of fluorescence and carotenoid content increased in stems with the increasing of drought stress. 6 d after re-hydration, new
leaves budded from stems. In the re-watered plants, the chloroplast function was restored and Chl a fluorescence returned to a similar level as in the control plants. This improved hydraulic adjustment in plant triggered
a positive effect on ion flow in the tissues and increased shoot electrical admittance. Thus R. soongorica plants are able to sustain drought stress through leaf abscission and keep part of Chl content in stems. 相似文献
11.
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
12.
Single treatment of expanding radish leaves with N1-(2-chloro-4-pyridyl)-N2-phenylurea (4-PU-30) lead to the stimulation of root cambial tissue activity and root growth. Leaf thickness, the volume
of chlorophyll (Chl) containing cells per unit leaf area, starch content in the chloroplasts, and the Chl content increased
simultaneously. These alterations were associated with increased leaf net photosynthetic rate and stomatal conductance in
treated plants.
This study was supported by the Bulgarian National Foundation for Scientific Researches (Contract B-413). 4-PU-30 was kindily
provided by Prof. K. Shudo, Faculty of Pharmaceutical Sciences, University of Tokyo, Japan. We wish also to thank Dr. T. Tsonev
for valuable advises. 相似文献
13.
Diurnal and seasonal changes in photosynthetic characteristics, leaf area dry mass (ADM), and reducing sugar and total chlorophyll (Chl) contents of leaves of Frantoio, Leccino, and Maurino olive cultivars were investigated in Central Italy. Leaf net photosynthetic rate (P
N) per unit leaf area changed during the growing season and during the day, but the cultivar did not significantly influence the changes. In both young and one-year-old leaves the highest P
N values were observed in October, while the lowest values were recorded in August and December; during the day the highest P
N values were generally found in the morning. The pattern of photosynthetic response to photosynthetic photon flux density (PPFD) of leaves was similar in the three genotypes. Sub-stomatal CO2 concentration (C
I) tended to increase when P
N decreased. The increase in C
I was accompanied by a stomatal conductance to water vapor (g
S) decrease. In general, P
N and dark respiration rate (R
D) were correlated. Transpiration rate (E), with no differences between the cultivars, increased from April to July, decreased greatly in August, then increased in October and finally decreased again in December. Leaf water content increased from April to June, remained high until mid July, decreased significantly in August, remaining constant until December with no differences associated with the cultivar. In both young and one-year-old leaves, the leaf water content per unit leaf area was slightly greater in Frantoio than in the other two cultivars. The one-year-old leaves had a higher Chl content than the young ones. The cultivar did not substantially influence the leaf reducing sugar content which decreased from April to August, when it reached the lowest level, then increased rapidly until October. During the day the reducing sugar content did not change significantly. The leaf ADM was slightly higher in Frantoio than in the other cultivars and one-year-old leaves had higher values than the young ones. Leaf ADM decreased from April to June and then tended to increase until December. During the day there were no substantial variations. 相似文献
14.
Photosynthesis in Drought-Adapted Cassava 总被引:5,自引:0,他引:5
After 45 d of limited water supply, cassava (Manihot esculenta Crantz) exhibited pronounced reduction in shoot growth, high leaf fall, and decreased stomatal conductance. However, the water status of the remaining leaves was unaffected. This was combined with an amplified heliotropic response and drooping which minimises radiant energy interception at mid-day, suggesting that leaves are sensitive to high irradiance (I). In well-irrigated plants, CO2-saturated oxygen evolution and net photosynthetic rate (P
N) in air were markedly higher (5-fold) in young (expanding) leaves than in mature leaves. Water limitation did not strongly modify CO2-saturated oxygen evolution but it altered P
N in air for both types of leaves, although differently. The mature leaves of drought-adapted plants displayed residual rate of P
N and deteriorated photosystem 2 (PS2) photochemistry estimated from chlorophyll (Chl) a fluorescence measurements. In young leaves at moderate I, P
N was depressed by only 66 % in stressed plants. Moreover, the photochemical quenching of Chl a fluorescence and the quantum efficiency of PS2 photochemistry in young leaves were comparable in both control and stressed plants. In contrast at high I, P
N was almost null and marked decreases in the two fluorescence parameters were apparent. Hence the strong heliotropic response and drooping displayed by young leaves under water limitation is an important strategy for avoiding inactivation of P
N by high I and therefore for cassava tolerance to drought. 相似文献
15.
Kandelia candel (L.) Druce is the dominant mangrove species on the west coast of northern Taiwan. We have measured the net photosynthetic
rate (P
N) and chlorophyll (Chl) a fluorescence of seedlings grown at combinations of two nitrogen (0.01 and 0.1 mM) and two NaCl (250 and 430 mM NaCl) controls.
With the same nitrogen level, seedlings grown at higher salinity (HS) had a significantly lower P
N and stomatal conductance (g
s) than those at lower salinity (LS). An increase in nitrogen availability significantly elevated P
N and g
s of the LS-grown seedlings. Compared to dark adapted leaves, the maximum quantum yield of photosystem 2 (PS2) (Fv/Fm) of leaves exposed to PFDs of 1200 and 1600 μmol m-2 s-1 for 2 h was significantly reduced. The degree of Fv/Fm reduction differed among leaves of the four types of treated plants. Chl fluorescence quenching analysis revealed differences
among the examined plants in coefficients of non-photochemical and photochemical quenching.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
16.
Effects of rhizobia inoculation and nitrogen fertilization on photosynthetic physiology of soybean 总被引:4,自引:0,他引:4
Plant growth, contents of photosynthetic pigments, photosynthetic gas exchange, and chlorophyll (Chl) fluorescence in soybean
[Glycine max (L.) Merr. cv. Heinong37] were investigated after it was inoculated with Sinorhizobium fredii USDA191 or treated with 5 mM (NH4)2SO4 (N5) and 30 mM (NH4)2SO4 (N30), respectively. In the plants following N5 fertilization, not only plant biomass, leaf area, and Chl content, but also
net photosynthetic rate (P
N), stomatal conductance (g
s), carboxylation efficiency (CE), maximum photochemical efficiency (Fv/Fm) of photosystem 2 (PS2), and quantum yield of PS2 (ΦPS2) were markedly improved as compared with the control plants. There were also positive effects on plant growth and plant photosynthesis
after rhizobia inoculation, but the effects were much less than those of N5 fertilization. For N30 plants there were no significant
positive effects on plant growth and photosynthetic capacity. Plant biomass, P
N, and g
s were similar to those of N-limited (control) plants. ΦPS2 and photochemical quenching (qP) were obviously declined while content of carotenoids and non-photochemical quenching (qN) were significantly enhanced in N30 treated plants. This indicated that excess N supply may cause some negative effects on
soybean plants. 相似文献
17.
The effect of benzyladenine (BA) and ascorbic acid (AA) on relative water content, proline accumulation, net photosynthetic rate (PN), chlorophyll (Chl) content and nitrate reductase (NR) activity, under sufficient water supply and moisture stress was studied in senna (Cassia angustifolia Vahl.) at seedling, vegetative, flowering and pod formation stages. AA treatment resulted in a higher accumulation of proline at all the stages of growth. Both BA and AA enhanced PN, Chl content and NR activity, and ameliorate the negative effect of water stress. 相似文献
18.
Plants of Nicotiana benthamiana (Gray) (60 d old) were mechanically inoculated by a spreading of the fourth and fifth leaves with inoculum with or without plum pox potyvirus (PPV). Changes in growth parameters and selected photosynthetic characteristics were followed in control and inoculated plants in the locally affected leaves (LA) during 11 d after inoculation (DAI), in systemically affected leaves immature at time of inoculation (SAI) during 14–25 DAI, and in systemically affected leaves developed after the inoculation (SAD) during 28–39 DAI. The pure mechanical damage caused by inoculation induced a decrease in the net photosynthetic rate (P
N) in LA and SAD leaves, and an increase in the steady-state value of the non-photochemical chlorophyll (Chl) fluorescence quenching qN. The qN increase appeared in certain time intervals in all measured leaves on plants, so it could be regarded as indication of a systemic reaction of plant to the local mechanical injury. The viral infection developed in LA leaves and spread to SAI and SAD leaves was documented by the ELISA-DASI method. The plant height and area of SAI and SAD leaves were lower in infected plants. The combined effect of mechanical damage and viral infection caused a decrease in P
N only in LA and SAD leaves. In SAD leaves, an increased relative height of the J step (VJ) in the O-J-I-P Chl fluorescence transient together with a lower B/A band ratio of thermoluminescence glow curves reflected a damage to the acceptor side of photosystem 2 (PS2) caused by the viral infection, and a faster kinetics of the induction of the photochemical quenching coefficient qP of Chl fluorescence indicated a faster QA
– re-oxidation in the remaining undamaged centres of PS2. 相似文献
19.
The response of Brassica carinata hybrids and their parents to moisture stress at different growth stages was studied. B.
carinata 226 was found to be susceptible to stress at pre-flowering and post-flowering stages while B. carinata 241 at flowering
stage. Neither the changes in stomatal conductance nor in chlorophyll content could fully explain the reduction in net photosynthetic
rate (PN) induced by stress. B. carinata 241 had higher leaf water potential (ψw) although, it had lower PN compared to B. carinata 226. Both the parents had lower PN as well as leaf ψw. The stress response of PN in hybrids followed that in their respective female parents.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
20.
X. D. Niu G. R. Li Z. H. Kang J. L. Huang G. X. Wang 《Russian Journal of Plant Physiology》2012,59(5):691-695
The physiological photosynthetic characteristics and antioxidant enzyme system of the high-chlorophyll rice (Oryza sativa L.) mutant (Gc) and its wild type (Zhenshan 97B) were compared and analyzed. Resulting data showed that the total chlorophyll (Chl) and Chl b contents in the Gc mutant were significantly increased by 19.0 and 81.7%, respectively, while the increase in Chl a and thylakoid membrane protein contents was insignificant. The net photosynthetic rate (P N) was significantly higher in the mutant; stomatal conductance, intercellular CO2 concentration, and transpiration rate decreased significantly, and water-use efficiency increased significantly, indicating the higher photochemical efficiency of the mutant. The chlorophyll fluorescence parameters: electron transport rate and effective quantum yield of PSII photochemistry of the mutant were significantly higher than those of Zhenshan 97B. The nonphotochemical quenching of the mutant under light adaptation increased by 52.3%. The enzymatic activity of superoxide dismutase, peroxidas, and catalase in the mutant roots and leaves were all higher than those for the wild-type plants. It is believed that the higher activity of antioxidant enzymes in the mutant may be an important factor making difficult the photo-inactivation of Chl, and thus, increasing the content of Chl, especially Chl b. 相似文献