95 resultados para Chlorophyll fluorescence


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Commercial farming of the intertidal brown alga Hizikia fusiformis (Harvey) Okamura in China and South Korea in the sea depends on three sources of seedlings: holdfast-derived regenerated seedlings, young plants from wild population and zygote-derived seedlings. Like many successfully farmed seaweed species, the sustainable development of Hizikia farming will rely on a stable supply of artificial seedlings via sexual reproduction under controlled conditions. However, the high rate of detachment of seedlings after transfer to open sea is one of the main obstacles, and has limited large-scale application of zygote-derived seedlings. To seek the optimal condition for growing seedlings on substratum in land-based tanks for avoidance of detachment in this investigation, young seedlings were grown in both outdoor tanks exposed directly to sunlight and in indoor raceway tanks in reduced, filtered sunlight. Results showed that young seedlings, immediately after fertilization, could withstand a daily fluctuation of direct solar irradiance up to a level of 1800 mu mol photons m(-1)s(-1), and maintained a faster growth rate than seedlings grown in indoor tanks. Detailed experiments by use of chlorophyll fluorescence measurements further demonstrated that the overnight (12 h) recovery of optimal fluorescence quantum yield (F-v/F-m) of seedlings after 1 h treatment at 40 degrees C was 98%, and the 48 h recovery of F-v/F-m of seedlings after 1 h exposure to 1800 mu mol m(-2)s(-1) was 92%. Forty-one-day-old seedlings showed no significant decrease of optimal fluorescence quantum yield at salinity ranging from 30 to 5 ppt for a treatment up to 17 h. Six-hour desiccation treatment did not have any influence on the optimal fluorescence quantum yield. Exposure to 18 mmol L-1 sodium hypochlorite for 10 min did not damage the PSII efficiency, and thus could be used to remove epiphytic algae. The strong tolerance of young seedlings to high temperature, high irradiance, low salinity and desiccation found in this investigation supports the view that mass production of Hizikia seedlings should be performed in ambient light and temperature instead of in shaded greenhouse tanks.

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Laminaria japonica, Undaria pinnatifida, Ulva lactuca, Grateloupia turuturu and Palmaria palmata are Suitable species that fit the requirements of a seaweed-animal integrated aquaculture system in terms of their viable biomass, rapid growth and promising nutrient uptake rates. fit this investigation, the responses of the optimal chlorophyll fluorescence yield of the five algal species in tumble Culture were assessed at a temperature range of 10 similar to 30 degrees C. The results revealed that Ulva lactuca was the most resistant species to high temperature, withstanding 30 degrees C for 4 h without apparent decline in the optimal chlorophyll fluorescence yield. While the arctic alga Palmaria palmata was the most vulnerable one, showing significant decline in the optimal chlorophyll fluorescence yield at 25 degrees C for 2 h. The cold-water species Laminaria japonica, however, demonstrated strong ability to cope with higher temperature (24 similar to 26 degrees C) for shorter time (within 24 h) without significant decline in the optimal chlorophyll fluorescence yield. Grateloupia turuturu showed a general decrease in the optimal chlorophyll fluorescence yield with the rising temperature from 23 to 30 degrees C, similar to the temperate kelp Undaria pinnatifida. Changes of chlorophyll fluorescence yields of these algae were characterized differently indicating the existence of species-unique strategy to cope with high light. Measurements of the optimal chlorophyll fluorescence yield after short exposure to direct solar irradiance revealed how long these exposures could be without significant photoinhibition or with promising recovery in photosynthetic activities. Seasonal pattern of alternation of algal species in tank culture in the Northern Hemisphere at the latitude of 36 degrees N was proposed according to these basic measurements.

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The cold-water subtidal brown alga Laminaria japonica has been commercially fanned in the Far East and has been on top of all marine-fanned species in terms of farming area and annual output worldwide. The successful trials of transplantation of young sporophytes from the north to the south in winter along the Chinese coast in the 1950s led to the spreading of cultivation activities down to a latitude of 25-26 degrees N. Up to today, nearly 50% of the annual output of this farmed alga, as a cold-water species, comes from the sub-tropical south in China. The demand to have high-temperature-tolerant strains/ecotypes in farming area calls for a practical method to judge and select the desired parental plants for breeding programs and for seedling production. In this paper, we report our results on using chlorophyll fluorescence measurement and short-term growth performance in tank culture to estimate the temperature tolerance of offspring from two populations, Fujian Farmed Population (FFP) sampled from Fujian province (latitude: 25-26 degrees N) in subtropical area and Qingdao Wild Population (QWP) sampled from Qingdao (latitude: 36 degrees N). Contrary to what has been usually thought, the results revealed that offspring from Qingdao wild population in the north showed better performance both in short-term growth and survival rates and in optimal quantum efficiency (F-v/F-m) when exposed to higher temperature (20-25 degrees C). This result was further confirmed by fluorescence quenching analysis. QWP distributed along the southern distribution limit at a latitude of 36 degrees N in the Pacific west coast is thus taken as a more ideal one than the fanned population in subtropical region as a source of parental plants for breeding high-temperature-tolerant varieties. (c) 2006 Elsevier B.V. All rights reserved.

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A study was carried out to examine the effect of dynamic photosynthetically active photon flux density (PPFD) on photoinhibition and energy use in three herbaceous species, prostrate Saussurea superba, erect-leaved S. katochaete, and half-erect-leaved Gentiana straminea, from the Qinghai-Tibet Plateau. Chlorophyll fluorescence response was measured under each of three sets of high-low PPFD combinations: 1700-0, 1400-300, and 1200-500 mu mol m(-2) s(-1), illuminating in four dynamic frequencies: 1, 5, 15, and 60 cycles per 2 h. The total light exposure time was 2h and the integrated PPFD was the same in all treatments. The highest frequency of PPFD fluctuation resulted in the lowest photochemical activity, the highest level of non-photochemical quenching, and the greatest decrease of F-v/F-m (maximal photochemical efficiency of PSII). The 5 and 15 cycles per 2h treatments resulted in higher photochemical activity than the 1 cycle per 2h treatment. The 1700-0 PPFD combination led to the lowest photochemical activity and more serious photoinhibition in all species. S. superba usually exhibited the highest photochemical activity and CO2 uptake rate, the lowest reduction of F-v/F-m,F- and the smallest fraction of energy in thermal dissipation. With similar fractions of thermal dissipation, S. katochaete had relatively less photoinhibition than G. straminea owing to effective F-o quenching. The results suggest that high frequency of fluctuating PPFD generally results in photoinhibition, which is more serious under periods of irradiation with high light intensity. (c) 2005 Elsevier B.V. All rights reserved.

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The chlorophyll fluorescence in soybean leaves was observed by a portable fluorometer CF-1000 under field conditions. On clear days, F-0 increased while F, and F-v/F-m decreased gradually in the morning. At midday F-O reached its maximum while F-v and F-v/F-m reached their minimum. The reverse changes occurred in the afternoon. At dusk these parameters could return to levels near those at dawn. Following exposure to a strong sunlight for more than 3 h, the dark-recovery process displayed three phases: (1) slow increases in F-0, F-v and F-v/F-m within the first hour; (2) a faster decrease in F-0 and faster increases in F-v and F-v/F-m within subsequent two hours; (3) a slow decrease in F-0 and slow increases in F-v and F-v/F-m within the fourth hour. In comparison with darkness, weak irradiance had no stimulating effect on the recovery from photoinhibition. Hence the photoinhibition in soybean leaves is mainly the reflection of reversible inactivation of some photosystem 2 reaction centres, but not the result of D1 protein loss.

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The chlorophyll fluorescence kinetics of marine red alga Grateloupia turutunt Yamada, green alga Ulva pertusa Kjellm and brown alga Laminaria japonica Aresch during natural sustained dehydration were monitored and investigated. The pulse amplified modulation (PAM) system was used to analyze the distinct fluorescence parameters during thallus dehydration. Results proved that the fluorescence kinetics of different seaweed all showed three patterns of transformation with sustained water loss. These were: 1) peak kinetic pattern (at the early stage of dehydration fluorescence enhanced and quenched subsequently, representing a normal physiological state). 2) plateau kinetic pattern (with sustained water loss fluorescence enhanced continuously but quenching became slower, finally reaching its maximum). 3) Platform kinetic pattern (fluorescence fell and the shape of kinetic curve was similar to plateau kinetic pattern). A critical water content (CWC) could be found and defined as the percentage of water content just prior to the fluorescence drop and to be a significant physiological index for evaluation of plant drought tolerance. Once thallus water content became lower than this value the normal peak pattern can not be recovered even through rehydration, indicating an irreversible damage to the thylakoid membrane. The CWC value corresponding to different marine species were varied and negatively correlated with their desiccation tolerance, for example. Laminaria japonica had the highest CWC value (around 90%) and the lowest dehydration tolerance of the three. In addition, a fluorescence "burst" was found only in red algae during rehydration. The different fluorescence parameters F-o, F-v and F-v, F-m were measured and compared during water loss. Both F-o and F-v increased in the first stage of dehydration but F-v/F-m. kept almost constant. So the immediate response of in vivo chlorophyll fluorescence to dehydration was an enhancement. Later with sustained dehydration F-o increased continuously while F-v decreased and tended to become smaller and smaller. The major changes in fluorescence (including fluorescence drop during dehydration and the burst during rehydration) were all attributed to the change in F-o instead of F-v This significance of F-o indicates that it is necessary to do more research on F-o as well as on its relationship with the state of thylakoid membrane.

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, C4C3 1nifAdctnifA37dct;dct40nifA 2108/ mL5 mmol/L (NH4)2SO430 mmol/L (NH4)2SO4 3150mol photons m-2s-115mol photons m-2s-177; 4PEPCPCRpmi

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157. 5mm315. Omm472. 5mm630. Omm425/2028/23 4157. 5mm315. Omm>>>> 4157. 5mm 44PSII157. 5mm630. Omm 4157. 5mm630. Omrn

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Cathaya argyrophylla100%45%3%3Pnmax(CE)3%1(LCP)(LSP)3%6h45%Pnmax(CE)(LCP)(LSP)1 0-40cm50%;;10cm80%;;

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(Pinus armandi)23 30'-3630'8850'-11330'13: 1)152-3 2)(EIS) 3)(15) 4) 5)36KD 6)36KD 7)4680nm670nm670nm 8)a(Fv/Fo)(Fv/Fm)(Qp)(Qn)QnQp 36KD680nm4(Fv/Fo)(Fv/Fm)

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(ABA)(Pn)(C02)(CE)II (PSII)(PSII)ABAPSII(Fv/Fm)1025mol L-I ABA750mol L-1ABA25mol L-lABAABAPnCEPS II(qP)(NPQ)(qm)Fv/FmABAPsnABA(V)(A)(Z)(V+A+Z)ABAABAPsIIPn(SOD)(APX)(DHAR)(GR)(AsA)(DHAsA)(GSH)(GSSH)ABAMehler-peroxidase III(300molm-2 S-l)655nm700-770 nmI(PSI)II(PSII)1Psn( Fml)PSII( Frri2)20nunPsn2l2PSIIDTTPsII( Fv/Fm)PSII(F0')20minPSIIPSII(B)PSI(a)ABA7PSII(Fm2)Fm1/Fm21-1ABA(qm)NEMABAqm12ABA77KF684/F732ABA 25mol L-l ABA7LT1STC02PsIILTST( Fv/Fm)(CE)(Pn)(Gs)LTST1500mol m-2 s-1Fv/FmLTFv/Fm60minSTFv/FmPS IIPnCELTLT(NPQ)MDASTNPQMDASTLTABAC02

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"5 1 0100200400 mM NaCl;050100150 mM NaCl5IIFv/FmFv/FmPSIIqP;CO2CO2;4CO2CO2PSII4 2 36484245CO2CO2Fv/FmFv/FmqPPSII55 3 30;42MDA42 4 PSII0~800 mMPSIIFv/Fm400 mM800mM NaCl(3040)PSII 5 304230354045504245PSIIFv/Fm;42PSII 6 ;MGDGDGDGPG;42"

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PSIIPSIIPSIIPSIIPSIIPSII 1 00.20.40.60.8M NaCl12ChlacarotenoidPCAPC 2 PS IIPS II 3 TLWestern PS IIOEC33PS II;TL B-bandQ-band0-0.6M NaClB-band0.8M NaClSS ;Fm JIPPS IIOEC33S 4 OJIPJIP-testTLPS II JIP-testoEo,QA-QB ;QA-QB QBPQPQQB;TL B-bandQ-bandQAQBPSII 5 PS II 6 PS IIPSIIPSIIQA QBPS IIPSIIPSIIPSII 7 WesternPSIIPSIIPSIICP43CP47OEC33 8 PS IIPC/chlaAPC/chla;IIPS IIPS II;DIo/RC;TRo/RC;I PSII

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IIPSIIPSIIPSIIQA-PSIIPSII 1.PS II PSIIFv/FmFv/Fm5-15% 2.QA-QB PQQBQA-QB(160 ms)(2 ms)S2QA- 4sQAQBPQQBQA-S25II 3. 77K580nm436nmPS IF725F751IPBSPS IIII643nmPBSPS IIIIIICP43CP47 .TLS2QA-S2QB-S2QA-S2QB-TLPSIIQB/QB-QAQBQAQB 5. OJIPKSTLS1S2S2S3OJIP