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1.
Background
The electron transport chain, Rubisco and stomatal conductance are important in photosynthesis. Little is known about their combined responses to heat treatment at different temperatures and following recovery in grapevines (Vitis spp.) which are often grown in climates with high temperatures.Methodology/Findings
The electron transport function of photosystem II, the activation state of Rubisco and the influence of stomatal behavior were investigated in grapevine leaves during heat treatments and following recovery. High temperature treatments included 35, 40 and 45°C, with 25°C as the control and recovery temperature. Heat treatment at 35°C did not significantly (P>0.05) inhibit net photosynthetic rate (P n). However, with treatments at 40 and 45°C, P n was decreased, accompanied by an increase in substomatal CO2 concentration (C i), decreases in stomatal conductance (g s) and the activation state of Rubisco, and inhibition of the donor side and the reaction center of PSII. The acceptor side of PSII was inhibited at 45°C but not at 40°C. When grape leaves recovered following heat treatment, P n, gs and the activation state of Rubisco also increased, and the donor side and the reaction center of PSII recovered. The increase in P n during the recovery period following the second 45°C stress was slower than that following the 40°C stress, and these increases corresponded to the donor side of PSII and the activation state of Rubisco.Conclusions
Heat treatment at 35°C did not significantly (P>0.05) influence photosynthesis. The decrease of P n in grape leaves exposed to more severe heat stress (40 or 45°C) was mainly attributed to three factors: the activation state of Rubisco, the donor side and the reaction center of PSII. However, the increase of P n in grape leaves following heat stress was also associated with a stomatal response. The acceptor side of PSII in grape leaves was responsive but less sensitive to heat stress. 相似文献2.
Changes of photosynthesis under blue light were examined in the ABA-overproducing 7B-1 mutant in tomato. Net photosynthetic rate (P N), stomatal conductance (g s), intrinsic water-use efficiency (WUEi) and chlorophyll (a+b) [Chl (a+b)] content in leaves of different insertion (1st, 4th and 9th ones) were measured in 5-, 7- and 9-week-old plants. P N, g s, and Chl (a+b) content were mostly similar in young leaves of 7B-1 and wild type (WT) plants. With the aging of leaves, a blue-light-induced increase in P N and g s to steady-state was delayed and steady-state values of P N and g s were lower in 7B-1 plants compared with WT. Steady-state values of WUEi were increased in 4th and 9th leaves of 7B-1 plants compared with WT. The results can be explained by the higher endogenous level of ABA in 7B-1 plants and their lower sensitivity to ABA in earlier growth stage. 相似文献
3.
C. Wang H. Z. She X. B. Liu D. Hu R. W. Ruan M. B. Shao L. Y. Zhang L. B. Zhou G. B. Zhang D. Q. Wu Z. L. Yi 《Photosynthetica》2017,55(1):77-84
Tartary buckwheat (Fagopyrum tataricum Gaertn) has been praised as one of green foods for humans in the 21st century. Effects of fertilization on leaf photosynthetic characteristics and grain yield of tartary buckwheat has not been yet reported in detail. Our experiment was set as a split-plot factorial. The main plots and subplots were designed by fertilizer ratio and rate as: NPK 1:1:1 (A1), NPK 1:4:2 (A2), NPK 1:2:3 (A3), and 300 (B1), 450 (B2), and 600 (B3) kg (NPK) ha–1. Our results showed that the grain yield was significantly and positively correlated with the net photosynthetic rate (P N), stomatal conductance (g s), transpiration rate (E), PAR, stomatal limitation value (Ls), chlorophyll content (SPAD value), and leaf area index (LAI), while significantly and negatively correlated with intercellular CO2 concentration (C i) and water-use efficiency (WUE). The grain yield, P N, g s, E, PAR, Ls, SPAD, and LAI increased and then decreased with enhanced fertilization, and their maximum values appeared in the A2B2 treatment. The C i and WUE decreased and then increased with enhanced fertilization, and their minimum values appeared in the A2B2 treatment. Our results suggested that fertilization had significant effects on the leaf photosynthetic capacity and grain yield of tartary buckwheat Yunqiao 1, and the best fertilization strategy was 450 kg ha–1 with NPK 1:4:2. 相似文献
4.
Imaging of photochemical yield of photosystem II (PSII) computed from leaf chlorophyll fluorescence images and gas-exchange measurements were performed on Rosa rubiginosa leaflets during abscisic acid (ABA) addition. In air ABA induced a decrease of both the net CO2 assimilation (An) and the stomatal water vapor conductance (gs). After ABA treatment, imaging in transient nonphotorespiratory conditions (0.1% O2) revealed a heterogeneous decrease of PSII photochemical yield. This decline was fully reversed by a transient high CO2 concentration (7400 μmol mol−1) in the leaf atmosphere. It was concluded that ABA primarily affected An by decreasing the CO2 supply at ribulose-1,5-bisphosphate carboxylase/oxygenase. Therefore, the An versus intercellular mole fraction (Ci) relationship was assumed not to be affected by ABA, and images of Ci and gs were constructed from images of PSII photochemical yield under nonphotorespiratory conditions. The distribution of gs remained unimodal following ABA treatment. A comparison of calculations of Ci from images and gas exchange in ABA-treated leaves showed that the overestimation of Ci estimated from gas exchange was only partly due to heterogeneity. This overestimation was also attributed to the cuticular transpiration, which largely affects the calculation of the leaf conductance to CO2, when leaf conductance to water is low. 相似文献
5.
M. Xu W. Duan P. G. Fan B. H. Wu L. J. Wang L. Ma D. D. Archbold S. H. Li 《Russian Journal of Plant Physiology》2014,61(3):397-408
Low sink demand provided by pod removal and stem girdling of beans (Vicia faba, cv. Daqingshan) (-Sink) induced a significantly lower net photosynthetic rate (P n), stomatal conductance (g s), internal CO2 concentration (C i), and transpiration rate (E) compared with pod and root sink retention (CK). This depression in P n was due to stomatal limitation. Low sink demand of -Sink plants resulted in a higher leaf sucrose content, but a lower sucrose content in guard cells. Moreover, the significant accumulation of H2O2 and ABA were observed in both leaves and guard cells of -Sink plants. The most intensive electron dense deposit of cerium perhydroxides, produced by H2O2 reaction with cerium chloride, was present in the cell walls, especially the dorsal walls of guard cells. Immunogold electron-microscopy localization of ABA showed that ABA was distributed in ventral walls of guard cells and the intercellular space of mesophyll cells of -Sink leaves in contrast to CK plants. Application of exogenous sucrose to isolated bean leaves increased H2O2 and ABA contents. H2O2 and ABA in leaves was likely generated by two independently regulated pathways, each affected by the high sucrose concentration induced by low sink demand. Increased sucrose in leaves in response to low sink demand may have caused the increase of H2O2 and ABA, and their accumulation in mesophyll cells and guard cells was likely the primary cause for stomatal closure under low sink demand. 相似文献
6.
Two teak (Tectona grandis L.f.) phenotypes differing in their leaf length/breadth ratios were subjected to water stress by withholding water supply for three weeks. Growth rates of whole plants, developing leaves (1st and 2nd from shoot apices), and 2nd and 3rd internodes were higher in broad leaved (BL) phenotype than in narrow leaved (NL) phenotype before and after imposing water stress treatment. However, the effect of water stress on these parameters was higher in the BL phenotype than in the NL one. Diurnal course of net photosynthetic rate (P N) of 3rd or 4th leaves from shoot apices measured under well-watered conditions was higher for the NL than BL phenotype. P N, stomatal conductance (g s), and transpiration rate (E) in both phenotypes were negatively affected by water stress and their decline under water stress was significantly higher in the BL than NL plants. 相似文献
7.
To understand the interactive effects of O3 and CO2 on rice leaves; gas exchange, chlorophyll (Chl) fluorescence, ascorbic acid and glutathione were examined under acute (5
h), combined exposures of O3 (0, 0.1, or 0.3 cm3 m−3, expressed as O0, O0.1, or O0.3, respectively), and CO2 (400 or 800 cm3 m−3, expressed as C400 or C800, respectively) in natural-light gas-exposure chambers. The net photosynthetic rate (P
N), maximum (Fv/Fm) and operating (Fq′/Fm′) quantum efficiencies of photosystem II (PSII) in young (8th) leaves decreased during O3 exposure. However, these were ameliorated by C800 and fully recovered within 3 d in clean air (O0 + C400) except for the O0.3 + C400 plants. The maximum PSII efficiency at 1,500 μmol m−2 s−1 PPFD (Fv′/Fm′) for the O0.3 + C400 plants decreased for all measurement times, likely because leaves with severely inhibited P
N also had a severely damaged PSII. The P
N of the flag (16th) leaves at heading decreased under O3 exposure, but the decline was smaller and the recovery was faster than that of the 8th leaves. The Fq′/Fm′ of the flag leaves in the O0.3 + C400 and O0.3 + C800 plants decreased just after gas exposure, but the Fv/Fm was not affected. These effects indicate that elevated CO2 interactively ameliorated the inhibition of photosynthesis induced by O3 exposure. However, changes in antioxidant levels did not explain the above interaction. 相似文献
8.
Plants of Podophyllum hexandrum, collected from lower, mid, and upper distribution limits in alpine Himalaya were studied under greenhouse conditions to
evaluate the photosynthetic response. Net photosynthetic rates (P
N), stomatal conductance (g
s), and efficiency of carbon uptake increased with altitude. The maximum P
N and g
s were measured in the considered population during the 3–6th week of development. P
N and g
s decreased on an average by 58 and 48 % from maximum rates reached around 4th week to the 10th week of growth, respectively. The photosynthetic response in the three ecotypes appeared to be genetically controlled. 相似文献
9.
The levels of stomatal, mesophyll and biochemical limitations in CO2 assimilation of ‘Bluecrop’ highbush blueberry leaves were compared at two different levels of leaf water potential. The leaf water potentials were ?1.49 and ?1.94 MPa in daily-irrigated (DI) and non-irrigated (NI) shrubs, respectively. The NI shrubs represented plants under moderate water stress. Mesophyll conductance (g m) and chloroplastic CO2 concentration (C c) were estimated by combined measurements of gas exchange and chlorophyll fluorescence under various intercellular CO2 concentrations (C i). Net CO2 assimilation rates (A n) as a function of C c were used for calculating maximum carboxylation efficiency (α cmax) at the real sites of CO2 assimilation. Maximum A n (A nmax) from the light response curves at 400 μmol mol?1 air of ambient CO2 concentration (C a) were lower in the leaves of NI shrubs than in those of DI ones. However, electron transport rates were higher in the leaves of NI shrubs than in those of DI ones. The decrease in CO2 assimilation following water stress may be caused by a decrease in g m rather than a decrease in stomatal conductance (g s) according to limitation analysis. Limitation rates by g s, calculated at 400 μmol mol?1 air of C a in A n-C i curves, were not significantly different between the leaves of DI and NI shrubs. However, limitation rates by g m from A n-C c curves were significantly higher in the leaves of NI shrubs than in those of DI ones. Maximum carboxylation efficiency (α cmax) values calculated from the A n-C c curve, contrary to those calculated from the A n-C i curve, were higher in the leaves of NI shrubs than in those of DI ones. Consequently, mesophyll limitation than stomatal and biochemical limitations mainly down-regulated the photosynthesis in the leaves of ‘Bluecrop’ blueberry shrubs during moderate water stress. 相似文献
10.
L. Zhang S. Xiao Y. J. Chen H. Xu Y. G. Li Y. W. Zhang F. S. Luan 《Photosynthetica》2017,55(3):478-490
Ozone (O3) is important air pollutant inducing severe losses of horticultural production. Cultivars of the same species, but with different leaf colors, may differ in their ozone sensitivity. However, it has not been clarified yet if different leaf coloration influences such a sensitivity. In this study, two purple-leafed and two green-leafed cultivars of Pakchoi were selected for ozone fumigation (240 ± 20 nmol mol–1, 09:00–16:00 h). Elevated O3 decreased chlorophyll content, increased anthocyanin (Ant) content, damaged cell membrane integrity, enhanced antioxidative enzyme activities, depressed photosynthetic rate (P N) and stomatal conductance (g s), inhibited maximal quantum yield (Fv/Fm) and effective quantum yield [YII] of PSII photochemistry, and caused visible injury. Purple-leafed cultivars with higher Ant contents were more tolerant than green-leafed cultivars as indicated by lower relative enhancement in malondialdehyde content and lower relative losses in P N, g s, Fv/Fm, and YII. The higher ability to synthesize Ant in the purple-leafed cultivars contributed to their higher photoprotective ability. 相似文献
11.
Background
Water deficit (WD) decreases photosynthetic rate (A) via decreased stomatal conductance to CO2 (gs) and photosynthetic metabolic potential (Apot). The relative importance of gs and Apot, and how they are affected by WD, are reviewed with respect to light intensity and to experimental approaches.Scope and Conclusions
With progressive WD, A decreases as gs falls. Under low light during growth and WD, A is stimulated by elevated CO2, showing that metabolism (Apot) is not impaired, but at high light A is not stimulated, showing inhibition. At a given intercellular CO2 concentration (Ci) A decreases, showing impaired metabolism (Apot). The Ci and probably chloroplast CO2 concentration (Cc), decreases and then increases, together with the equilibrium CO2 concentration, with greater WD. Estimation of Cc and internal (mesophyll) conductance (gi) is considered uncertain. Photosystem activity is unaffected until very severe WD, maintaining electron (e−) transport (ET) and reductant content. Low A, together with photorespiration (PR), which is maintained or decreased, provides a smaller sink for e−, causing over-energization of energy transduction. Despite increased non-photochemical quenching (NPQ), excess energy and e− result in generation of reactive oxygen species (ROS). Evidence is considered that ROS damages ATP synthase so that ATP content decreases progressively with WD. Decreased ATP limits RuBP production by the Calvin cycle and thus Apot. Rubisco activity is unlikely to determine Apot. Sucrose synthesis is limited by lack of substrate and impaired enzyme regulation. With WD, PR decreases relative to light respiration (RL), and mitochondria consume reductant and synthesise ATP. With progressing WD at low A, RL increases Ci and Cc. This review emphasises the effects of light intensity, considers techniques, and develops a qualitative model of photosynthetic metabolism under WD that explains many observations: testable hypotheses are suggested.Key words: Water stress, photosynthesis, photorespiration, stomata, ATP synthase, ATP, photoinhibition, electron transport, Rubisco, fluorescence, sucrose, mesophyll conductance 相似文献12.
S. M. Gupta A. Agarwal B. Dev K. Kumar O. Prakash M. C. Arya M. Nasim 《Photosynthetica》2016,54(1):138-142
Photosynthetic parameters including net photosynthetic rate (PN), transpiration rate (E), water-use efficiency (WUE), and stomatal conductance (gs) were studied in indoor C3 plants Philodendron domesticum (Pd), Dracaena fragans (Df), Peperomia obtussifolia (Po), Chlorophytum comosum (Cc), and in a CAM plant, Sansevieria trifasciata (St), exposed to various low temperatures (0, 5, 10, 15, 20, and 25°C). All studied plants survived up to 0°C, but only St and Cc endured, while other plants wilted, when the temperature increased back to room temperature (25°C). The PN declined rapidly with the decrease of temperature in all studied plants. St showed the maximum PN of 11.9 μmol m?2 s?1 at 25°C followed by Cc, Po, Pd, and Df. E also followed a trend almost similar to that of PN. St showed minimum E (0.1 mmol m?2 s?1) as compared to other studied C3 plants at 25°C. The E decreased up to ≈4-fold at 5 and 0°C. Furthermore, a considerable decline in WUE was observed under cold stress in all C3 plants, while St showed maximum WUE. Similarly, the gs also declined gradually with the decrease in the temperature in all plants. Among C3 plants, Pd and Po showed the maximum gs of 0.07 mol m?2 s?1 at 25°C followed by Df and Cc. However, St showed the minimum gs that further decreased up to ~4-fold at 0°C. In addition, the content of photosynthetic pigments [chlorophyll a, b, (a+b), and carotenoids] was varying in all studied plants at 0°C. Our findings clearly indicated the best photosynthetic potential of St compared to other studied plants. This species might be recommended for improving air quality in high-altitude closed environments. 相似文献
13.
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. 相似文献
14.
小麦和玉米叶片光合-蒸腾日变化耦合机理 总被引:8,自引:0,他引:8
植物叶片光合-蒸腾耦合是陆地生态系统碳-水耦合的基础.已有研究将叶片光合-蒸腾耦合笼统归因于气孔的共同控制作用,缺乏对其耦合机理的全面分析.选择华北地区大田作物冬小麦(C3)和夏玉米(C4)为研究对象,分别在小麦开花期和玉米拔节期选择典型晴天进行叶片光合蒸腾日变化观测(8:00-18:00).结果发现:1)光合速率(An)、蒸腾速率(Tr)以及光合有效辐射(PAR)、叶片表面温度(T)和气孔导度(gs)均表现出单峰日变化特征,峰值出现在正午前后;2)An-Tr具有极显著线性正相关关系(小麦和玉米的相关系数分别为0.75**和0.92**,回归直线斜率分别为1.99和3.62);3)PAR、T和gs与An和Tr有线性正相关关系;4)PAR-An与PAR-Tr、T-An与T-Tr、gs-An与gs-Tr的回归直线形态非常相似.分析认为:1)在光合-蒸腾耦合特征方面,C3作物小麦和C4作物玉米叶片光合-蒸腾都有明显的线性耦合关系,但两者的耦合关系特征存在明显差异,玉米的An-Tr线性回归斜率要明显大于小麦;2)在光合-蒸腾耦合机理方面,日变化中PAR、T和gs同时受太阳辐射调控与An、Tr发生趋向相同、形态相似且近似同步的变化,因此PAR-An与PAR-Tr、T-An与T-Tr、gs-An与gs-Tr具有形态相似的线性关系,这保证了在PAR、T和gs等调控因子发生较大变化的日变化过程中光合-蒸腾保持良好的线性耦合关系. 相似文献
15.
The source-sink relationship is one of major determinants of plant performance. The influence of reproductive sink demand on light-saturated photosynthesis (Pmax), dark respiration (RD), stomatal conductance (gs), intrinsic water-use efficiency (WUEi), contents of soluble sugar (SSC), nitrogen, carbon, and photosynthetic pigments was examined in blueberry (Vaccinium corymbosum L. cv. ‘Brigitta’) during the final stage of rapid fruit growth. Measurements were performed three times per day on developed, sun-exposed leaves of girdled shoots with 0.1, 1, and 10 fruit per leaf (0.1F:L, 1F:L, and 10F:L, respectively) and nongirdled shoots bearing one fruit per leaf (NG). Girdling and lower fruit amount induced lower Pmax, gs, N, and total chlorophyll (Chl) and higher WUEi, SSC, RD, Chl a/b ratio and carotenoids-to-chlorophylls ratio (Car/Chl) for the 1F:L and 0.1F:L treatments. The impact of girdling was counterbalanced by 10F:L, with NG and 10F:L having similar values. Variables other than Pmax, RD, gs, WUEi, and SSC were unaffected throughout the course of the day. Pmax and gs decreased during the course of the day, but gs decreased more than Pmax in the afternoon, while WUEi was increasing in almost all treatments. SSC increased from the morning until afternoon, whereas RD peaked at noon regardless of the treatment. Generally, Pmax was closely and negatively correlated to SSC, indicating that sugar-sensing mechanisms played an important role in regulation of blueberry leaf photosynthesis. With respect to treatments, Pmax and N content were positively related, while RD was not associated to substrate availability. The enhanced Car/Chl ratio showed a higher photoprotection under the lower sink demand. Changes in the source-sink relationship in ‘Brigitta’ blueberry led to a rearrangement of physiological and structural leaf traits which allowed adjusting the daily balance between carbon assimilation and absorbed light energy. 相似文献
16.
Diurnal changes in needle gas exchange in alpine Pinus pumila during snow-melting and summer seasons
Atsushi Ishida Takashi Nakano Seikoh Sekikawa Emiko Maruta Takehiro Masuzawa 《Ecological Research》2001,16(1):107-116
Pinus pumila (Pallas) Regel. is a dominant dwarf tree in alpine regions of Japan. The possible factors limiting the net photosynthetic rate (Pn) of the needles of P. pumila were examined in the snow-melting (May) and the summer (August) seasons. In August, in situ maximum Pn was 20 mol kg–1 needle s–1 in the current-year needles and 25 mol kg–1 needle s–1 in the 1-year-old needles. Diurnal trends of Pn in August were positively related to fluctuations in photosynthetic photon flux density (PPFD) and no midday depression of Pn was found, indicating that a decrease in PPFD rather than an increase in needle-to-air vapor pressure deficit (W) might cause the reduction of Pn. Both stomatal conductance (gs) and Pn were lower in May than in August. In May, Pn and gs were almost zero in the morning, but gradually increased with decreasing W, reaching maximum Pn values (4 mol kg–1 needle s–1) and gs (60 mmol kg–1 needle s–1) at 16.00 hours. The daytime Pn in May was positively related to gs. Relative water content in the exposed needles above the snow in May was 83%, which was far above the lethal level. This indicates that the water flow from stems or soils to needles was enough to compensate for a small amount of water loss due to the low gs in May, although the water supplied to needles would be impeded by the low temperatures. Thus, the reduced gs in May would be important for avoiding needle desiccation, and would result in a reduced Pn. 相似文献
17.
Abstract Using an open-system leaf chamber, gas exchange measurements on attached leaves of 3-4-year-old Golden Delicious apple trees, made through two seasons, provided data from which the parameters of a leaf photosynthesis model could be derived. The equation is: where C1 is internal CO2 concentration and Qp is the incident quantum flux. There was considerable leaf to leaf variation in the values of the parameters but no clear seasonal trends were established. The initial slope (a) had an average value of about 2.5 × 10?3 mg μmol?1? (i.e. quantum yield ~ 0.057); the mesophyll conductance (gm) was about 3.5 mm s?1 in extension leaves of trees carrying fruit and 2.5 mm s?1 in extension leaves of defruited trees. Differences between the values of gm for spur leaves with and without subtending fruits were not significant; 2.5 mm s?1 may be used. Dark respiration (Rd, mg m?2 s?1) increased exponentially with temperature (T°C); Rd~ 0.006 exp (0.09 T). At saturating photon flux density Pn was linearly related to Ci, up to Ci~ 250 mg m?3. Optimum temperatures for Pn were slightly different in the two years and were in the range 16-26°C. 相似文献
18.
Pierre Bancal 《Annals of botany》2009,103(8):1315-1324
Background and Aims
Nitrogen (N) remobilization is the major source of N for grain filling in wheat, the other being N uptake after anthesis (Nup); however, variations in remobilization efficiency are not fully understood. It is hard to tell whether the source or the sink effects predominate, because N in the culm at anthesis (Nant) correlates strongly with both N remobilization (Nrem) and grain number (Gn), respectively the main source and the main sink.Methods
A pot experiment was thus designed to assess the relative contributions of the source and sink to Nrem regulation. Using two cultivars of winter wheat (Triticum aestivum, ‘Apache’ and ‘Autan’), three pre-anthesis and two post-anthesis N fertilization levels were applied in order to vary the N sources, while ear trimming at anthesis reduced sink size.Key Results
Unlike results observed at a scale of m2, the equation binding Nant to Nrem exhibited a negative intercept, challenging the concept of nitrogen remobilization efficiency. Before ear trimming, Gn fitted well to Nant, with a slope dependent on genotype. To obtain a sink variable that was less correlated with Nant, the difference δGn was calculated between actual grain number and that which could be predicted from culm N before trimming. A multiple regression then predicted Nrem (r2 = 0·95) from Nant, Nup and δGn, with fitting unbiased by fertilization treatment, trimming or genotype.Conclusions
In untrimmed culms, δGn had a negligible effect, so that Nrem could be fitted to Nant and Nup only: grain N filling appeared to be determined by sources only (Nant and Nup), not by sink, and the reduction of Nrem by Nup was quantified. In these ‘normal’ cases, the regulation of Nrem should thus be located within the N sources themselves. In contrast, ear-trimming needs to be considered with caution as it introduced a sink limitation on Nrem; moreover one with an important genotype effect.Key words: Triticum aestivum, winter wheat, source/sink, grain filling, nitrogen uptake, grain number, nitrogen harvest index, nitrogen remobilization efficiency, genotype × environment 相似文献19.
The influence of a probiotic additive and aromatic oils from medicinal and spicy plants on the basic production parameters
and on the incidence of intestinal disorders of weaned pigs (weaning at the age of 30–32 days) was compared in two trials
in a commercial pig fattening farm (Michalovce, Slovakia). In the first trial, an experimental (n
ex = 38) and a control group (n
co = 32) were used. A commercial probiotic additive containing Enterococcus faecium M-74 (6 × 108 CFU/g) and IgY antibodies (920 mg/g dried activated egg matter) against pig Rotavirus and different strains of Escherichia coli (K88, K99, 987P, F18) were added to feed mixture of the experimental group from 30th to 40th day (12 × 108 CFU/g) and subsequently from 40th to 50th day (6 × 108 CFU/g) of age. The second trial was performed with three groups of pigs (n
ex1 = 28, n
ex2 = 24, n
co = 28). Aromatic oils isolated from sage (Salvia officinalis L., Labiateae) or oregano (Origanum vulgare L., Lamiaceae) were added to feed mixtures of the 1st (90 mL/100 kg) and 2nd experimental group (35 mL/100 kg), respectively, from 32th to 53th day of age. A statisticaly non-significant decrease of the incidence of diarrhoeal diseases was observed in the experimental
groups of both trials as follows: in the 1st trial by 43.41%, whereas in the 2nd trial by 20.03% (1st exp. group) and 6.72% (2nd exp. group) in comparison with the control groups. The daily weight gains increased in the 1st trial by 42.95 g/day, while in the 2nd trial by 69.52 g/day (1st exp. group) and 105.23 g/day (2nd exp. group; p < 0.05) compared with controls.
Presented at the Second Probiotic Conference, Košice, 15–19 September 2004, Slovakia. 相似文献
20.
In order to investigate the effect of chromosome doubling on ozone tolerance, we compared the physiological responses of a
diploid honeysuckle (Lonicera japonica Thunb.) and its autotetraploid cultivar to elevated ozone (O3) exposure (70 ng g−1, 7 h d−1 for 31 d). Net photosynthetic rate (P
N) of both cultivars were drastically (P<0.01) impaired by O3. Although there were significantly positive correlation between P
N and stomatal conductance (g
s) in both cultivars under each treatment, the decreased g
s in O3 might be the result rather than the cause of decreased P
N as indicated by stable or increasing the ratio of intercellular to ambient CO2 concentration(C
i/C
a). P
N under saturating CO2 concentration (P
Nsat) and carboxylation efficiency (CE) significantly decreased under O3 fumigation, which indicated the Calvin cycle was impaired. O3 also inhibited the maximum efficiency of photosystem II (PSII) photochemistry in the dark-adapted state (Fv/Fm), actual quantum yield of PSII photochemistry (ΦPSII), electron transport rate (ETR), photochemical quenching coefficient (qP), non-photochemical quenching (NPQ), the maximum
in vivo rate of Rubisco carboxylation (Vcmax) and the maximal photosynthetic electron transport rate (Jmax) which demonstrated that the decrease in P
N of the honeysuckle exposed to elevated O3 was probably not only due to impairment of Calvin cycle but also with respect to the light-harvesting and electron transport
processes. Compared to the diploid, the tetraploid had higher relative loss in transpiration rate (E), (g
s), (P
Nsat), Vcmax and Jmax. This result indicated that the Calvin cycle and electron transport in tetraploid was damaged more seriously than in diploid.
A barely nonsignificant (P=0.086) interaction between O3 and cultivar on P
N suggested a higher photosynthetic sensitivity of the tetraploid cultivar. 相似文献