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232. Photosynthetic limitations caused by different rates of water-deficit induction in Glycine max and Vigna unguiculata
- Creator:
- Bertolli, S. C., Rapchan, G. L., and Souza, G. M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, cowpea, photosynthesis, rapid and slow water-deficit induction, recovery, soybean, 2, and 58
- Language:
- Multiple languages
- Description:
- Plants are constantly subjected to variations in their surrounding environment, which affect their functioning in different ways. The influence of environmental factors on the physiology of plants depends on several factors including the intensity, duration and frequency of the variation of the external stimulus. Water deficit is one of the main limiting factors for agricultural production worldwide and affects many physiological processes in plants. The aim of this study was to analyse the effects of different rates of induced water deficit on the leaf photosynthetic responses of soybean (Glycine max L.) and cowpea (Vigna unguiculata L.). The plants were subjected to two types of water deficit induction: a rapid induction (RD) by which detached leaves were dehydrated by the exposure to air under controlled conditions and a slow induction (SD) by suspending irrigation under greenhouse conditions. The leaf gas exchange, chlorophyll (Chl) a fluorescence, and relative water content (RWC) were analysed throughout the water-deficit induction. V. unguiculata and G. max demonstrated similar dehydration as the soil water percentage declined under SD, with V. unguiculata showing a greater stomatal sensitivity to reductions in the RWC. V. unguiculata plants were more sensitive to water deficit, as determined by all of the physiological parameters when subjected to RD, and the net photosynthetic rate (PN) was sharply reduced in the early stages of dehydration. After the plants exposed to the SD treatment were rehydrated, V. unguiculata recovered 65% of the PN in relation to the values measured under the control conditions (initial watering state), whereas G. max recovered only 10% of the PN. Thus, the better stomatal control of V. unguiculata could enable the maintenance of the RWC and a more efficient recovery of the PN than G. max., S. C. Bertolli, G. L. Rapchan, and G..M. Souza., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
233. Photosynthetic nitrogen- and water-use efficiency of acacia and eucalypt seedlings as afforestation species
- Creator:
- Novriyanti, E., Watanabe, M., Makoto, K., Takeda, T., Hashidoko, Y., and Koike, T.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, afforestation, fast growing species, photosynthetic nitrogen-use efficiency, photosynthetic rate, photosynthetic water-use efficiency, 2, and 58
- Language:
- Multiple languages
- Description:
- The ecophysiological traits of acacia and eucalypt are important in assessing their suitability for afforestation. We measured the gas-exchange rate, the leaf dry mass per area (LMA) and the leaf nitrogen content of two acacia and four eucalypt species. Relative to the eucalypts, the acacias had lower leaf net photosynthetic rate (PN), lower photosynthetic nitrogen-use efficiency (PNUE), higher water-use efficiency (WUE), higher LMA and higher leaf nitrogen per unit area (N area). No clear differences were observed within or between genera in the maximum rate of carboxylation (Vcmax) or the maximum rate of electron transport (Jmax), although these parameters tended to be higher in eucalypts. PNUE and LMA were negatively correlated. We conclude that acacias with higher LMA do not allocate nitrogen efficiently to photosynthetic system, explaining why their PN and PNUE were lower than in eucalypts., E. Novriyanti ... [et al.]., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
234. Photosynthetic parameters of two invasive tree species of the Brazilian Pantanal in response to seasonal flooding
- Creator:
- Dalmagro, H. J., de Lobo, F. A., Vourlitis, G. L., Dalmolin, Â. C., Antunes Jr., M. Z., Ortíz, C. E. R., and Nogueira, J. de S.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, cerrado, Curatella americana L., invasive species, neotropical Vochysia divergens Pohl, Pantanal, wetlands, 2, and 58
- Language:
- Multiple languages
- Description:
- a1_The Pantanal is the largest wetland in the world with extremely high plant and animal diversity, but large areas have been invaded by Vochysia divergens Pohl (Vochysiaceae), a tree that is native to the Amazon Basin, and Curatella americana L. (Dilleniaceae), a tree that is native to the Brazilian savanna (cerrado). V. divergens is reportedly floodadapted, thus its ability to invade the Pantanal may not be surprising, but the invasion of C. americana is counterintuitive, because this species is adapted to the well-drained soils of the cerrado. Thus, we were interested in comparing the photosynthetic capacity, in terms of CO2 conductance, carboxylation, and electron transport of these species over a seasonal flooding cycle. Given that V. divergens is reportedly flood-adapted, we predicted that this species would have a higher photosynthetic capacity than C. americana, especially under flooding. To test this hypothesis we measured the photosynthetic CO2 response (PN/Cc) of V. divergens and C. americana within 1 year to determine, if photosynthetic capacity varied systematically over time and between species. Contrary to our hypothesis, V. divergens did not always have a higher photosynthetic capacity than C. americana. Rather, species differences were influenced by temporal variations in flooding and the leaf age. Leaf CO2 assimilation and photosynthetic capacity of both species were lower during the flood period, but the differences were not statistically significant. The physiological performance of both species was strongly related to leaf N and P concentrations, but P limitation appeared to be more important than N limitation for these species and ecosystem. Photosynthetic capacity was higher and more stable for V. divergens, but such an advantage did not result in a statistically significant increase in PN., a2_Our results suggest that both species are tolerant to flooding even though they are adapted to very different hydrological conditions. Such physiological plasticity, especially for C. americana, might be a key feature for the ability to survive and persist in the seasonally flooded Pantanal., H. J. Dalmagro ... [et al.]., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
235. Photosynthetic performance of Anabaena variabilis PCC 7937 under simulated solar radiation
- Creator:
- Singh, S. P., Rastogi, R .P., Sinha, R. P., and Häder, D.-P.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, cut-off filters, cyanobacteria, effective quantum yield of PSII, pulse amplitude modulated fluorometer, ultraviolet-B radiation, 2, and 58
- Language:
- Multiple languages
- Description:
- In vivo chlorophyll fluorescence analysis reflecting the photosystem II functionality was investigated in the cyanobacterium Anabaena variabilis PCC 7937 under simulated solar radiation in a combination with various cut-off filters (WG 280, WG 295, WG 305, WG 320, WG 335, WG 345, and GG 400) to assess the effects of photosynthetically active radiation (PAR), ultraviolet-A (UV-A), and ultraviolet-B (UV-B) radiations on photosynthesis. The photosynthetic activity (PA) was severely inhibited immediately after 10 min of exposure to high PAR, UV-A, and UV-B radiations compared with low PAR grown control samples. After 1 h of exposure, PA of 17.5 ± 2.9% was detected in the high PAR exposed samples compared with the control, while only a trace or no PA was observed in the presence of ultraviolet radiation (UVR). A recovery of PA was recorded after 2 h of the exposure, which continued for next 4, 8, 12, and 24 h. After 24 h of the exposure, PA of 57.5 ± 1.9%, 36.1 ± 11.7%, 23.5 ± 3.3%, 22.3 ± 5.2%, 20.8 ± 6.7%, 13.2 ± 6.6%, and 21.6 ± 9.5% was observed compared with the control sample in 400, 345, 335, 320, 305, 295, and 280 nm cut-off filters-covered samples, respectively. The relative electron transport rate, measured after 24 h exposure, showed also a disturbance in electron transfer between the two photosystems under the high PAR and UVR treatments relative to the control samples, suggesting the inhibition of photosynthesis. This study suggests that both high PAR and UVR inhibited the photosynthetic performance of A. variabilis PCC 7937 by damaging the photosynthetic apparatus, however, photoprotective mechanisms evolved by the organism allowed an immediate repair of ecologically important machinery, and enabled its survival., S. P. Singh ... [et al.]., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
236. Photosynthetic performance of Lycoris radiata var. radiata to shade treatments
- Creator:
- Zhou, S. B., Liu, K., Zhang, D., Li, Q. F., and Zhu, G. P.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, chlorophyll fluorescence, diurnal course, iradiance, leaf anatomy, leaf morphology, net photosynthetic rate, and shade
- Language:
- Multiple languages
- Description:
- The effects of shade on the growth, leaf photosynthetic characteristics, and chlorophyll (Chl) fluorescence parameters of Lycoris radiata var. radiata were determined under differing irradiances (15, 65, and 100% of full irradiance) within pots. The HI plants exhibited a typical decline in net photosynthetic rate (PN) during midday, which was not observed in MI- and LI plants. This indicated a possible photoinhibition in HI plants as the ratio of variable to maximum fluorescence (Fv/Fm) value was higher and the minimal fluorescence (F0) was lower in the, and LI plants. Diurnal patterns of stomatal conductance (gs) and transpiration rate (E) were remarkably similar to those of PN at each shade treatments, and the intercellular CO2 concentration (Ci) had the opposite change trend. Under both shading conditions, the light saturation point, light compensation point and photon-saturated photosynthetic rate (Pmax) became lower than those under full sunlight, and it was the opposite for the apparent quantum yield (AQY). The higher the level of shade, the lower the integrated daytime carbon gain, stomatal and epidermis cell densities, specific leaf mass (SLM), bulb mass ratio (BMR), leaf thickness, and Chl a/b ratio. In contrast, contents of Chls per dry mass (DM), leaf area ratio (LAR), leaf mass ratio (LMR), leaf length, leaf area and total leaf area per plant increased under the same shade levels to promote photon absorption and to compensate for the lower radiant energy. Therefore, when the integrated daytime carbon gain, leaf area and total leaf area per plant, which are the main factors determining the productivity of L. radiata var. radiata plant, were taken into account together, this species may be cultivated at about 60-70% of ambient irradiance to promote its growth. and S. B. Zhou ... [[et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
237. Photosynthetic performance of regenerated protoplasts from disintegrated cells of Bryopsis hypnoides (Chlorophyta)
- Creator:
- Lü, F., Wang, G. C., and Niu, J. F.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, Bryopsis hypnoides, chlorophyll fluorescence, imaging-PAM, oxygen measurements, protoplasts, and photosynthesis
- Language:
- Multiple languages
- Description:
- The photosynthetic performances of regenerated protoplasts of Bryopsis hypnoides, which were incubated in seawater for 1, 6, 12, and 24 h, were studied using chlorophyll (Chl) fluorescence and oxygen measurements. Results showed that for the regenerated protoplasts, the pigment content, the ratios of photosynthetic rate to respiration rate, the maximal photosystem II (PSII) quantum yield (Fv/Fm), and the effective PSII quantum yield (ΦPSII) decreased gradually along with the regeneration progress, indicated that during 24 h of regeneration there was a remarkable reduction in PSII activity of those newly formed protoplasts. We assumed that during the cultivation progress the regenerated protoplasts had different photosynthetic vigor, with only some of them able to germinate and develop into mature thalli. The above results only reflected the photosynthetic features of the regenerated protoplasts at each time point as a whole, rather than the actual photosynthetic activity of individual aggregations. Further investigation suggested a relationship between the size of regenerated protoplasts and their viability. The results showed that the middle-sized group (diameter 20-60 μm) retained the largest number of protoplasts for 24 h of growth. The changes in Fv/Fm and ΦPSII of the four groups of differently sized protoplasts (i.e. < 20, 20-60, 60-100, and > 100 μm) revealed that the protoplasts 20-60 μm in diameter had the highest potential activity of the photosynthetic light energy absorption and conversion for several hours. and F. Lü, G. C. Wang, J. F. Niu.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
238. Photosynthetic properties of Quercus × hispanica Lam. and Q. suber L. under harsh Central European winter conditions
- Creator:
- Holland, V. and Brüggemann, W.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, evergreen, frost stress, oak, photoinhibition, and xanthophyll cycle
- Language:
- Multiple languages
- Description:
- In search for new forestation tree species for future Central European climate conditions, Mediterranean evergreen oak taxa are investigated for their summer drought- and winter frost-hardiness. Here we report on the winter performance of the photosynthetic apparatus of Quercus × hispanica Lam. and its evergreen parental species Q. suber L. under extraordinary harsh winter conditions. Both taxa showed a strong decline of photosystem II (PSII) quantum efficiency (Fv/Fm) with a concomitant increase in the deepoxidation state (DES) of the xanthophyll pigments depending on (severe) frost events during winter, and these parameters significantly correlated with minimum air temperatures during periods of chronic photoinhibition at mid-winter, but not at the onset of winter in response to the first frost nights. Fv/Fm and DES correlated with each other in both taxa throughout the winter. and V. Holland, W. Brüggemann.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
239. Photosynthetic rate, needle longevity, and nutrient contents in Picea glehnii growing on strongly acidic volcanic ash soil in northern Japan
- Creator:
- Kayama, M., Satoh, F., and Koike, T.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, needle longevity, nitrogen retranslocation, nutrient physiology, photosynthetic rate, and solfatara spruce
- Language:
- Multiple languages
- Description:
- Picea glehnii Masters can grow in strongly acidic volcanic ash soil (pH 3.6) in northern Japan. We compared needle longevity, photosynthetic rate, and concentrations of elements in needles, in mature trees of P. glehnii growing in volcanic ash soil and in brown forest soil (pH 5.4). P. glehnii growing in volcanic ash soil showed suppressed photosynthetic rate and growth by the deficiency in nitrogen compared with its growth in brown forest soil. However, the younger needles of P. glehnii growing in volcanic ash soil maintained a high photosynthetic rate, as a result of large amounts of remobilized nitrogen from senesced needles. Needles of P. glehnii growing in volcanic ash soil did not show deficiencies in Ca, Mg, or K. Moreover, Al was at low levels in the needles, suggesting that P. glehnii was able to avoid Al toxicity by Al exclusion. P. glehnii thus exhibits great ability to adapt to an acidic environment. and M. Kayama, F. Satoh, T. Koike.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
240. Photosynthetic response of two shrubs to rainfall pulses in desert regions of northwestern China
- Creator:
- Liu, B., Zhao, W. Z., and Wen, Z. J.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, Calligonum mongolicum, Nitraria sphaerocarpa, photosynthetic parameters, rainfall pulse, response curves, 2, and 58
- Language:
- Multiple languages
- Description:
- Pulses of rainfall are particularly pivotal in controlling plant physiological processes in ecosystems controlled by limited water, and the response of desert plants to rainfall is a key to understanding the responses of desert ecosystems to global climatic change. We used a portable photosynthesis system to measure the responses of the diurnal course of photosynthesis, light-response curves, and CO2-response curves of two desert shrubs (Nitraria sphaerocarpa Maxim. and Calligonum mongolicum Turcz) to a rainfall pulse in a desert-oasis ecotone in northwestern China. The photosynthetic parameters, light- and CO2-response curves differed significantly before and after the rainfall pulse. Their maximum net photosynthetic rate (PN) values were 23.27 and 32.92 μmol(CO2) m-2 s-1 for N. sphaerocarpa and C. mongolicum, respectively, with corresponding maximum stomatal conductance (gs) values of 0.47 and 0.39 mol(H2O) m-2 s-1. The PN of N. sphaerocarpa after the rainfall was 1.65 to 1.75 times the value before rainfall, whereas those of C. mongolicum increased to approximately 2 times the prerainfall value, demonstrating the importance of the desert plants response by improving their assimilation rate to precipitation patterns under a future climate., B. Liu, W. Z. Zhao, Z. J. Wen., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public