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5392. Growth and photosynthetic response of two larches exposed to O3 mixing ratios ranging from preindustrial to near future
- Creator:
- Sugai, T., Kam, D.-G., Agathokleous, E., Watanabe, M., Kita, K., and Koike, T.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- homeostáza, homeostasis, dvoufázové, soutěže, odezva na dávku, hormeze, plasticita, biphasic, competition, dose-response, hormesis, plasticity, 2, and 581
- Language:
- Multiple languages
- Description:
- In this study, we questioned whether ground-level ozone (O3) induces hormesis in Japanese larch (Larix kaempferi) and its hybrid F1 (L. gmelinii var. japonica × L. kaempferi). In order to answer the question, we exposed seedlings of both taxa to four O3 treatments [ranging from ≈10 to 60 nmol(O3) mol-1] in open-top chambers for two consecutive growing seasons. We found a hormetic response in maximum photosynthetic rate (PNmax) at 1700 μmol(CO2) mol-1 and maximum rates of carboxylation (Vcmax) and electron transport (Jmax) in both larches. Stimulation of PNmax, Vcmax, and Jmax did not lead to suppressed plant productivity in Japanese larch, which followed a stress-tolerant strategy, but it did lead to suppressed plant productivity in hybrid larch which followed a competitive strategy. These findings are the first to suggest that stimulation of physiological functions by low O3 exposures may have negative consequences for larch reproduction., T. Sugai, D.-G. Kam, E. Agathokleous, M. Watanabe, K. Kita, T. Koike., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5393. Growth and photosynthetic responses in Jatropha curcas L. seedlings of different provenances to watering regimes
- Creator:
- Yin, C. Y., Pang, X. Y., Peuke, A. D., Wang, X., Chen, K., and Gong, R. G.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, water-use efficiency, carotenoids, chlorophyll fluorescence, gas exchange, 2, and 581
- Language:
- Multiple languages
- Description:
- Seedlings from four provenances of Jatropha curcas were subjected to 80, 50, and 30% of soil field capacity in potted experiments in order to study their responses to water availability. Our results showed that with the decline of soil water availability, plant growth, biomass accumulation, net photosynthetic rate, stomatal conductance (gs), and transpiration rate (E) decreased, whereas leaf carbon isotope composition (δ13C), leaf pigment contents, and stomatal limitation value increased, while maximal quantum yield of PSII photochemistry was not affected. Our findings proved that stomatal limitation to photosynthesis dominated in J. curcas under low water availability. The increase of δ13C should be attributed to the decrease in gs and E under the lowest water supply. J. curcas could adapt to low water availability by adjusting its plant size, stomata closure, reduction of E, increasing δ13C, and leaf pigment contents. Moreover, effects of provenance and the interaction with the watering regime were detected in growth and many physiological parameters. The provenance from xeric habitats showed stronger plasticity in the plant size than that from other provenances under drought. The variations may be used as criteria for variety/provenance selection and improvement of J. curcas performance., C. Y. Yin, X. Y. Pang, A. D. Peuke, X. Wang, K. Chen, R. G. Gong., and Seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5394. Growth and photosynthetic responses of soybean seedlings to maize shading in relay intercropping system in Southwest China
- Creator:
- Su, B. Y., Song, Y. X., Song, C., Cui, L., Yong, T. W., and Yang, W. Y.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, produktivita, sója, kukuřice, photosynthesis, productivity, soybean, Čína jihovýchodní, China, Southeastern, carbon accumulation, chlorophyll a fluorescence, photosynthetic pigment, planting pattern, intercropping system, maize, 2, and 581
- Language:
- Multiple languages
- Description:
- Intercropping, a traditional and worldwide cropping practice, has been considered as a paradigm of sustainable agriculture based on complementary mechanisms among different crop species. Soybean (Glycine max) is widely relay intercropped about 60 days before maize (Zea mays) harvest in Southwest China. However, shade caused by tall maize plants may be a limiting factor for soybean growth at a seedling stage. In field research, we studied the ecophysiological responses of two widely cultivated soybean varieties [Gongqiudou494-1 (GQD) and Gongxuan 1 (GX)] to maize shading in a relay intercropping system (RI) compared with monocropped soybean plants (M). Our results showed that soybean seedlings intercropped with maize exhibited significantly downregulated net photosynthetic rate (PN) (-38.3%), transpiration rate (-42.7%), and stomatal conductance (-55.4%) due to low available light. The insignificant changes in intercellular CO2 concentration and the maximum efficiency of PSII photochemistry suggested that the maize shading-induced depressions in PN were probably caused by the deficiency of energy for carbon assimilation. The significantly increased total chlorophyll (Chl) content (+27.4%) and Chl b content (+52.2%), with lowered Chl a/b ratios (-20.5%) indicated soybean plants adjusted their light-harvesting efficiency under maize shading condition. Biomass and leaf area index (LAI) of seedlings under RI decreased significantly (-78.7 and -71%, respectively) in comparison with M. Correlation analysis indicated the relative reduction in biomass accumulation was caused by the decline in LAI rather than PN, it affected negatively the final yields of soybean (32.8%). Cultivar-specific responses to maize shading were observed in respects of LAI, biomass, and grain yield. It indicated that GX might be a better cultivar for relay intercropping with maize in Southwest China., B. Y. Su, Y. X. Song, C. Song, L. Cui, T. W. Yong, W. Y. Yang., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5395. Growth and some photosynthetic characteristics of field grown Avena sativa under copper and lead stress
- Creator:
- Moustakas, M., Lanaras, T., Symeonidis, L., and Karataglis, S.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Description:
- A fíeld experiment was conducted to evaluate the effects of Cu and Pb on photosynthesis and growth characteristics of oats. The plants grown on the site with elevated levels of Cu-Pb were reduced in height and biomass, compared to control plants, and appeared chlorotic while the accumulations of both Cu and Pb in the above-ground parts were in the range considered to be phytotoxic. Cu and Pb led to a pronounced reduction (47 %) of chlorophyll (Chl) (a + b) content, accompanied by proportional changes in ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBPCO) activity. Hence Cu and Pb effects did not result in the destruction of the photosynthetic apparatus but in its coordinated reduction. Growth at the heavy metal contaminated site resulted in a decreased (7 %) quantum yield of photochemistry in photosystem 2 (PS2), as given by the ratio Fy/Fn, measured in dark adapted leaves in the field. The half-rise time (ti/2) from the initial (Fq) to maximal (F^) Chl fluorescence was increased, suggesting that the amount of active pigments associated with the photochemical apparatus decreased and that the functional Chl antennae size of the photosynthetic apparatus was smaller compared to the control plants. Although Cu and Pb affected the photosynthetic apparatus in multiple ways, the prevailing effect was that on RuBPCO activity, which in tum must háve limited the overall photosynthetic activity.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5396. Growth irradiance affects ureide accumulation and tolerance to photoinhibition in Eutrema salsugineum (Thellungiella salsuginea)
- Creator:
- Malik, V. M., Lobo, J. M., Stewart, C., Irani, S., Todd, C. D., and Gray, G. R.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, acclimation, allantoin, antioxidant, reactive oxygen species, 2, and 581
- Language:
- Multiple languages
- Description:
- Plants are able to acclimate to their growth light environments by utilizing a number of short- and long-term mechanisms. One strategy is to prevent accumulation of excess reactive oxygen species that can lead to photoinhibition of photosynthesis. Ureides, generated from purine degradation, have been proposed as antioxidants and involved in certain abiotic stress responses. Eutrema salsugineum (Thellungiella salsuginea) is an extremophilic plant known to exhibit a high degree of tolerance to a variety of abiotic stresses that invariably generate reactive oxygen species. In the present study we have investigated the possible role of the ureide metabolic pathway during acclimation to growth irradiance and its conference of tolerance to photoinhibition in Eutrema. Ureide accumulation was greater under high light growth which also conferred tolerance to photoinhibition at low temperature as measured by the maximal quantum yield of PSII photochemistry. This may represent an adaptive plastic response contributing to the extreme tolerance exhibited by this plant. Our results would provide evidence that ureide accumulation may be involved in abiotic stress as another defence mechanism in response to oxidative stress., V. M. Malik, J. M. Lobo, C. Stewart, S. Irani, C. D. Todd, G. R. Gray., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5397. Growth, biomass allocation, and phenology responses of pepper to elevated CO2 concentrations and different water and nitrogen supply
- Creator:
- Penuelas, J., Biel, C., and Estiarte, M.
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- Capsicum annuum\ chlorophyll, yield, SLA, root/shoot ratio, resource availability, leaf area, fruits, and flowers
- Language:
- Multiple languages
- Description:
- Fifty-day old plants of Capsicum anmmm L, with two developed leaves were placed into controlled environment chambers at atmospheric (350 cm^ m'^, ACO2) and elevated (700 cm^ m-^, ECO2) CO2 concentrations under different nitrogen and water supply. Plant response to ECO2 and the modulating effect of the availability of nitrogen and water were evaluated. CO2 effects were significant only after 40 d of treatment, An increase in plant growth and yield was found in ECO2 plants only under a good supply of both water (HW) and nitrogen (HN). Chlorophyll concentration responded only to N supply. Root/shoot ratio was higher under ECO2 only under low N (LN) and low water (LW) supply. Leaf area and specific leaf area decreased under ECO2. Flowering and fructification took plače earlier in ECO2 under FIN and FIW. Thus, all CO2 effects were modulated by the N and water supply and the duration of exposure.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5398. Growth, photosynthesis and ion balance of sesame (Sesamum indicum L.) genotypes in response to NaCl concentration in hydroponic solutions
- Creator:
- Bazrafshan, A. H. and Ehsanzadeh, P.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, draslík, sodík, photosynthesis, potassium, sodium, chlorophyll fluorescence, gas exchange, salinity, 2, and 581
- Language:
- Multiple languages
- Description:
- A hydroponic, greenhouse experiment was conducted to assess the effects of NaCl on growth, gas-exchange parameters, chlorophyll (Chl) content, and ion distribution in seven sesame (Sesamum indicum L.) genotypes (Ardestan, Varamin, Naz-Takshakhe, Naz-Chandshakhe, Oltan, Yekta, Darab). The plants were grown in 4-L containers and subjected to varying levels of salinity (0, 30, and 60 mM NaCl). After 42 days, salt treatments induced decreases of plant fresh and dry mass, total leaf area, and plant height in all genotypes. Increasing NaCl concentration caused significant, genotypedependent decrease in the net photosynthetic rate, stomatal conductance, Chl content, and maximum quantum efficiency of photosystem II, while it increased the intercellular CO2 concentration. Based on the dry matter accumulation under salinity, the genotypes were categorized in two groups, i.e., salt-tolerant and salt-sensitive. The impact of salt on plant ion concentrations differed significantly among the sesame genotypes and between both two groups. The plant Na+ concentrations were significantly lower in Ardestan, Darab, and Varamin genotypes than those found in the remaining genotypes. The highest plant K+ and Ca2+ concentrations together with the lowest Na+/K+ and Na+/Ca2+ ratios were observed in Ardestan, Varamin, and Darab genotypes. Our results indicated the presence of differences in salt response among seven sesame genotypes. It suggested that growth and photosynthesis could depend on ion concentrations and ratios in sesame., A. H. Bazrafshan, P. Ehsanzadeh., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5399. Growth, photosynthesis and nitrogen content in Japanese beech (Fagus crenata Bl.) seedlings grown under five irradiances
- Creator:
- Liang, Naishen, Nagayama, M., Nakata, M., and Maruyama, K.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Description:
- Acclimation to irradiance was investigated in seedlings of Japanese beech {Fagus crenata Bl.) grown under one of five irradiance regimes for three years. Inadiance (/) regimes covered the range of environmental conditions which this species normally would experience in Japanese beech forests: exposed [22.1 mol(quantum) m‘2 d'*, matching mean daily irradiance of exposed canopies], partially shaded [8.8, 2.7 and 1.5 mol(quantum) d'*, respectively, comparable to various midcanopies], and deeply shaded [0.5 mol(quantum) nu^ d"', equivalent to forest floor], There were consistent strong relationships between irradiance, growth performance and net photosynthetic rate (P^) for this species. Greater growth performance and were achieved as / increased, with aboveground height growth increasing as rapidly as basal diameter growth. This tiend was also observed in the leaf specific mass and leaf nitrogen content. Exposed plants had higher saturation I for (> 1400 |amol m'^ s‘*) than partially shaded plants (1180, 1100 and 753 pmol m‘2 s'', respectively). Higher leaf conductance, leaf specific mass and leaf nitrogen content correlated positively with higher Nevertheless, the beech seedlings adapted to deep shade by producing more total chlorophyll and requiring lower compensation / (Qq) at lower growth irradiances. Seedlings of Japanese beech were very tolerant to shade but capable of acclimating to strong I. Thus / is an important factor influencing growth and photosynthetic capacity of Japanese beech.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5400. Growth, photosynthesis, water relations and competition of the old-fieid species Abutilon theophrasti, Ambrosia trifida, and Helianihus annuus grown under controlied conditions
- Creator:
- Norman, F. and Martin, C.E.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Description:
- The effects of intra- and interspecific competition on growth, net photosynthetic rate (/^n), intemal CO2 concentration (cj), leaf conductance to CO2 (gi), and xylem leaf water potentials Q¥) were investigated among well-watered seedlings of the old-field species Abutilon theophrasíi. Ambrosia tri/ida, and Helianíhus annuus. In all comparisons, *F values of the target plants were unaffected by the presence of neighbors. On the other hand, revealed inhibitory effects of neighbors on A. theophrasíi and H. annuus. The above- and belowground biomass of all species was reduced in the presence of neighbors. Hence both inter- and intraspecific competition among seedlings may be important in influencing community stiucture in old-field communities.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public