Does age matter under winter photoinhibitory conditions? A case study in stems and leaves of European mistletoe (Viscum album)

2015 ◽  
Vol 42 (2) ◽  
pp. 175 ◽  
Author(s):  
Fátima Míguez ◽  
Beatriz Fernández-Marín ◽  
Antonio Hernández ◽  
José Maria Becerril ◽  
José Ignacio García-Plazaola
Keyword(s):  
Carbon Balance ◽  
Photosynthetic Activity ◽  
Photochemical Efficiency ◽  
Winter Season ◽  
Protein Composition ◽  
Woody Species ◽  
Viscum Album ◽  
Photochemical Efficiency Of Psii ◽  
Seasonal Acclimation

European mistletoe (Viscum album L.) is a hemiparasitic plant with perennial leaves and photosynthetic stems easily discernible according to their age. These properties make V. album the perfect species to (i) compare the mechanisms of seasonal acclimation of photosynthetic stems with those of leaves, and (ii) evaluate the influence of ageing in the efficiency of photosynthetic tissues. To achieve these general objectives, photosynthetic pigments, maximal photochemical efficiency of PSII (Fv/Fm), recovery kinetics and key thylakoidal proteins were analysed during winter and spring in leaves and at different age stems. During winter, some woody species are able to maintain photosynthetic activity, but at lower rates than during spring. In the case of V. album, photosynthetic relevance of green stems appears equal to leaves in terms of total area. Besides, mistletoe stems are able to maintain higher Fv/Fm and lower level of antioxidants than leaves, especially during winter season. The recovery from winter photoinhibition is also faster in stems than in leaves. Thylakoidal protein composition (mainly high levels of D1) also supports the idea of stems as main photosynthetic organs in V. album during winter. Further, in winter, the level of photoinhibition of V. album stems decreased concomitantly with ageing. This work highlights the importance of stem photosynthesis in plant carbon balance and demonstrates that ageing does not necessarily imply a loss of vitality in stems.

Inflight icing data gathering during routine flight operations — a case study

2001 ◽  
Vol 105 (1051) ◽  
pp. 501-516 ◽  
Author(s):  
A. P. Brown
Keyword(s):  
Data Gathering ◽  
Winter Season ◽  
Leading Edge ◽  
General Aviation ◽  
Data Sets ◽  
Large Droplet ◽  
Event Data ◽  
Flight Operations ◽  
Lower Corner

Abstract For the purpose of the design and certification of inflight icing protection systems for transport and general aviation aircraft, the eventual re-definition/expansion of the icing environment of FAR 25/JAR 25, Appendix C is under consideration. Such a re-definition will be aided by gathering as much inflight icing event data as reasonably possible, from widely-different geographic locations. The results of a 12-month pilot programme of icing event data gathering are presented. Using non-instrumented turboprop aircraft flying upon mid-altitude routine air transport operations, the programme has gathered observational data from across the British Isles and central France. By observing a number of metrics, notably windscreen lower-corner ice impingement limits, against an opposing corner vortex-flow, supported by wing leading edge impingement limits, the observed icing events have been classified as ‘small’, ‘medium’ or ‘large’ droplet. Using the guidance of droplet trajectory modelling, MVD values for the three droplet size bins have been conjectured to be 15, 40 and 80mm. Hence, the ‘large’ droplet category would be in exceedance of FAR/JAR 25, Appendix C. Data sets of 117 winter-season and 55 summer-season icing events have been statistically analysed. As defined above, the data sets include 11 winter and five summer large droplet icing encounters. Icing events included ‘sandpaper’ icing from short-duration ‘large’ droplets, and a singular ridge formation icing event in ‘large’ droplet. The frequency of ‘large’ droplet icing events amounted to 1 in 20 flight hours in winter and 1 in 35 flight hours in summer. These figures reflect ‘large’ droplet icing encounter probabilities perhaps substantially greater than previously considered. The ‘large’ droplet events were quite localised, mean scale-size being about 6nm.

scholarly journals Physiological and Biochemical Responses ofUlva proliferaandUlva linzato Cadmium Stress

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
He-ping Jiang ◽  
Bing-bing Gao ◽  
Wen-hui Li ◽  
Ming Zhu ◽  
Chun-fang Zheng ◽  
...  
Keyword(s):  
Amino Acids ◽  
Photochemical Efficiency ◽  
Cadmium Stress ◽  
Nutrient Content ◽  
Ulva Prolifera ◽  
Cadmium Resistance ◽  
Relative Growth ◽  
Biochemical Responses ◽  
Photochemical Efficiency Of Psii ◽  
Physiological And Biochemical

Responses ofUlva proliferaandUlva linzato Cd2+stress were studied. We found that the relative growth rate (RGR), Fv/Fm, and actual photochemical efficiency of PSII (Yield) of twoUlvaspecies were decreased under Cd2+treatments, and these reductions were greater inU. proliferathan inU. linza.U. proliferaaccumulated more cadmium thanU. linzaunder Cd2+stress. WhileU. linzashowed positive osmotic adjustment ability (OAA) at a wider Cd2+range thanU. prolifera.U. linzahad greater contents of N, P, Na+, K+, and amino acids thanU. prolifera. A range of parameters (concentrations of cadmium, Ca2+, N, P, K+, Cl−, free amino acids (FAAs), proline, organic acids and soluble protein, Fv/Fm, Yield, OAA, and K+/Na+) could be used to evaluate cadmium resistance inUlvaby correlation analysis. In accordance with the order of the absolute values of correlation coefficient, contents of Cd2+and K+, Yield, proline content, Fv/Fm, FAA content, and OAA value ofUlvawere more highly related to their adaptation to Cd2+than the other eight indices. Thus,U. linzahas a better adaptation to Cd2+thanU. prolifera, which was due mainly to higher nutrient content and stronger OAA and photosynthesis inU. linza.

scholarly journals Analysis of Catania Flash Flood Case Study by Using Combined Microwave and Infrared Technique

2014 ◽  
Vol 15 (5) ◽  
pp. 1989-1998 ◽  
Author(s):  
Francesco Di Paola ◽  
Elisabetta Ricciardelli ◽  
Domenico Cimini ◽  
Filomena Romano ◽  
Mariassunta Viggiano ◽  
...  
Keyword(s):  
Real Time ◽  
Flash Flood ◽  
Weather Prediction ◽  
Rapid Evolution ◽  
Cell Formation ◽  
Winter Season ◽  
National Research Council ◽  
Severe Weather ◽  
Synoptic Situation

Abstract In this paper, the analysis of an extreme convective event atypical for the winter season, which occurred on 21 February 2013 on the east coast of Sicily and caused a flash flood over Catania, is presented. In just 1 h, more than 50 mm of precipitation was recorded, but it was not forecast by numerical weather prediction (NWP) models and, consequently, no severe weather warnings were sent to the population. The case study proposed is first examined with respect to the synoptic situation and then analyzed by means of two algorithms based on satellite observations: the Cloud Mask Coupling of Statistical and Physical Methods (MACSP) and the Precipitation Evolving Technique (PET), developed at the National Research Council of Italy. Both of the algorithms show their ability in the near-real-time monitoring of convective cell formation and their rapid evolution. As quantitative precipitation forecasts by NWP could fail, especially for atypical convective events like in Catania, tools like MACSP and PET shall be adopted by civil protection centers to monitor the real-time evolution of deep convection events in aid to the severe weather warning service.

Chemical Composition of Woods of 37 Woody Species of Tamaulipan Thorn Scrub, Northeast Mexico: A Case Study

2020 ◽  
pp. 129-151
Author(s):  
Humberto Gonzalez Rodriguez ◽  
Ratikanta Maiti ◽  
Natalya S. Ivanova ◽  
Ch. Aruna Kumari
Keyword(s):  
Chemical Composition ◽  
Woody Species

scholarly journals THE INFLUENCE OF BIO-ALGEEN S90 ON THE GROWTHOF MULTIFLORA ROSE SEEDLINGS (Rosa multiflora Thunb.)

2019 ◽  
Vol 18 (3) ◽  
pp. 35-43
Author(s):  
Mariusz Szmagara ◽  
Krystyna Pudelska ◽  
Wojciech Durlak ◽  
Barbara Marcinek ◽  
Kamila Rojek
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photochemical Efficiency ◽  
Morphological Characteristics ◽  
Rosa Multiflora ◽  
Plant Growth And Development ◽  
Agent Based ◽  
Photochemical Efficiency Of Psii ◽  
Stimulate Plant Growth ◽  
Maximum Photochemical Efficiency ◽  
Natural Agent

Striving to intensify horticultural production, new and more effective bio-preparations are being sought to stimulate plant growth and development. Bio-algeen S90 is a natural agent based on sea algae, the high bi- ological activity of which results from the high content of natural growth regulators. The aim of the study was to verify the influence of Bio-algeen S90 on the growth, morphological characteristics and chlorophyll fluorescence of Rosa multiflora seedlings. The bio-preparation was applied one, two and three times at con- centrations: 0.1, 0.2, 0.4 and 0.6 mg.dm−3. Following parameters were measured to evaluate the response of plants to the bio-preparation: F0 – initial fluorescence, Fm – maximal fluorescence in the dark-adapted state, Fv/Fm – maximum photochemical efficiency of PSII. All concentrations of the bio-preparation and frequency of its application stimulated the number of shoots in a bush, the length of shoots and the diameter of the root crown of plants intended for budding. The most beneficial was the two-fold bio-preparation application at a concentration of 0.4 mg.dm–3. Bio-algeen also positively influenced the chlorophyll fluorescence parame- ters. The highest mean F0 and Fm values were recorded with the two-fold preparation treatment. There was no significant effect of the bio-preparation on the Fv/Fm index, which was within the range of 0.75–0.66.

scholarly journals Chemical Free Vegetable Cultivation and Outcomes in Winter Season in Bangladesh : A case study on BOP farmers in five districts

2017 ◽  
Vol 62 (1) ◽  
pp. 255-262
Author(s):  
Mansur Ahmed ◽  
Akinori Ozaki ◽  
Dipok K. Choudhury ◽  
Kazuo Ogata ◽  
Shoichi Ito ◽  
...  
Keyword(s):  
Winter Season ◽  
Vegetable Cultivation

Meteorological Analysis of the Sea Fog in Winter Season on Gyeonggi Bay, Yellow Sea: A Case Study for the 106-vehicle Pileup on February 11, 2015

2017 ◽  
Vol 79 ◽  
pp. 124-128
Author(s):  
Yoo-Keun Kim ◽  
Hyunsu Kim ◽  
Jang-Won Seo ◽  
Hye-Yeon An ◽  
Yo-Hwan Choi
Keyword(s):  
Yellow Sea ◽  
Winter Season ◽  
Sea Fog ◽  
Meteorological Analysis

scholarly journals Impacts of Restoration Projects on a Sahelian Woody Vegetation after 21 Years: The Simiri Plateaus (Niger) Case Study

2019 ◽  
pp. 1-12
Author(s):  
Laouali Abdou ◽  
Boubacar Moussa Mamoudou ◽  
Habou Rabiou ◽  
Ali Mahamane ◽  
Josiane Seghieri
Keyword(s):  
Vegetation Cover ◽  
Recovery Rate ◽  
Crop Yields ◽  
Basal Area ◽  
Tree Height ◽  
Woody Species ◽  
Woody Vegetation ◽  
Number Of Stems ◽  
Similar Site

To face the soil and vegetation degradation in Niger, anti-erosion structures, such as scarification of the surface of the ground, half-moons, benches, trenches, stony cordons, were built in 1989 on three Simiri plateaus. Native and introduced woody species were planted and grasses were sown within the structures. This study aims at evaluating what has become the restoration of the woody vegetation cover compared to an un-restored woody cover located on a nearby similar site. Dendrometric parameters and alpha and beta diversities of the four woody stands in 36 sampled plots were analyzed and compared. The following dendrometric values were found significantly lower in the control than in the restored stands: 3.9% against 12.4-16.8% for the recovery rate, 4.3 against 6.3-10.2 cm for the largest stem diameter, 0.2 against 0.8-1.2 m²/ha for the basal area, and 1.6 against 2.0-2.5 m for the tree height. However, the number of stems per trees was found significantly greater in the un-restored stand (6.6) than in the restored ones (1.8-2.7). The values of dendrometric parameters remained low, as well as the alpha and beta diversities whatever the stand. Nevertheless, population perceptions on the restoration impacts that were collected through focus groups indicated positive impacts on downstream crop yields.

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