Fonctionnement sympodial continu et multiplication végétative chez l’Arum italicum

1981 ◽  
Vol 59 (2) ◽  
pp. 238-250 ◽  
Author(s):  
A. Nougarède ◽  
P. Rondet
Keyword(s):  
Close Contact ◽  
Winter Season ◽  
Base Plate ◽  
Climatic Conditions ◽  
Continuous Growth ◽  
Asexual Multiplication ◽  
Storage Products ◽  
Bulbous Plant ◽  
Sympodial Growth ◽  
Arum Italicum

The vegetative and floral development of Arum italicum Mill. displays no resting period under western European climatic conditions. Between two flowering seasons several sympodial units ending with an inflorescence are successively built. The meristem of each new unit is generally initiated in the axil of a sagittate leaf of the preceding unit but it can also grow in a nonaxillary position at the base of the meristem. The leaves of the first unit spend the winter season above the ground. Their petiole sheaths surround all the later sympodial units. On each sympodial unit a number of axillary buds give rise to tunicated bulbils which provide for the asexual multiplication of the species. The ontogeny of the bulbils on the mother plant and their behaviour after they become autonomous are described, as well as those of young plantlets grown from seed germination. In rhizomes, bulbils, and plantlets the shoot apex is in close contact with a subapical region (base plate) built from interlocked leaf or scale bases which are rich in storage products. This base plate will give rise to a new rhizome. Although Arum italicum has a tuberous rhizome with sympodial growth, it has nevertheless some characters of a bulbous plant (base plate and bulbils) but it differs from it by continuous growth and development and the lack of dormancy of the bulbils.

scholarly journals Changes in Air Temperature and Snow Cover in Winter in Poland

Atmosphere ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 68
Author(s):  
Arkadiusz M. Tomczyk ◽  
Ewa Bednorz ◽  
Katarzyna Szyga-Pluta
Keyword(s):  
Snow Cover ◽  
Air Temperature ◽  
Winter Season ◽  
Primary Objective ◽  
Climatic Conditions ◽  
Cover Depth ◽  
North Eastern ◽  
Northern Regions ◽  
Maximum Air Temperature ◽  
Snow Cover Depth

The primary objective of the paper was to characterize the climatic conditions in the winter season in Poland in the years 1966/67–2019/20. The study was based on daily values of minimum (Tmin) and maximum air temperature (Tmax), and daily values of snow cover depth. The study showed an increase in both Tmin and Tmax in winter. The most intensive changes were recorded in north-eastern and northern regions. The coldest winters were recorded in the first half of the analyzed multiannual period, exceptionally cold being winters 1969/70 and 1984/85. The warmest winters occurred in the second half of the analyzed period and among seasons with the highest mean Tmax, particularly winters 2019/20 and 1989/90 stood out. In the study period, a decrease in snow cover depth statistically significant in the majority of stations in Poland was determined, as well as its variability both within the winter season and multiannual.

Field survey on frost damage to roof tiles under climatic conditions

2016 ◽  
Vol 34 (2) ◽  
pp. 135-149 ◽  
Author(s):  
Chiemi Iba ◽  
Ayumi Ueda ◽  
Shuichi Hokoi
Keyword(s):  
Field Survey ◽  
Winter Season ◽  
Frost Damage ◽  
Climatic Conditions ◽  
Weather Data ◽  
Measured Temperature ◽  
Content Type ◽  
Roof Tile ◽  
Deterioration Process ◽  
The Impact

Purpose – Frost damage is well-known as the main cause of roof tile deterioration. The purpose of this paper is to develop an analytical model for predicting the deterioration process under certain climatic conditions. This paper describes the results of a field survey conducted to acquire fundamental information useful to this aim. Design/methodology/approach – A field survey of roof tile damage by freezing was conducted in an old temple precinct in Kyoto, Japan. Using detailed observations and photographic recordings, the damage progress was clarified. To examine the impact of climatic conditions upon the damage characteristics, weather data and roof tile temperatures were measured and logged in the winter season. Findings – The deterioration process was observed under the climatic conditions associated with the measured temperature of the roof tiles. In particular, it was revealed that the orientation has a significant influence on increasing or decreasing the risk of frost damage. For certain distinctive forms of damage, the deterioration mechanisms were estimated from the viewpoint of the moisture flow and temperature distribution in the tile. Originality/value – This study contributes to the elucidation of the mechanism behind frost damage to roof tiles. The findings will guide the construction of a numerical model for frost damage prediction.

scholarly journals Atmospheric blocking induced by the strengthened Siberian High led to drying in west Asia during the 4.2 ka BP event – a hypothesis

2019 ◽  
Vol 15 (2) ◽  
pp. 781-793 ◽  
Author(s):  
Aurel Perşoiu ◽  
Monica Ionita ◽  
Harvey Weiss
Keyword(s):  
Climate Variability ◽  
Winter Season ◽  
Balkan Peninsula ◽  
Climatic Conditions ◽  
Boreal Winter ◽  
Winter Climate ◽  
Heterogeneous Distribution ◽  
Climate Conditions ◽  
Causal Explanations ◽  
Siberian High

Abstract. Causal explanations for the 4.2 ka BP event are based on the amalgamation of seasonal and annual records of climate variability that was manifest across global regions dominated by different climatic regimes. However, instrumental and paleoclimate data indicate that seasonal climate variability is not always sequential in some regions. The present study investigates the spatial manifestation of the 4.2 ka BP event during the boreal winter season in Eurasia, where climate variability is a function of the spatiotemporal dynamics of the westerly winds. We present a multi-proxy reconstruction of winter climate conditions in Europe, west Asia, and northern Africa between 4.3 and 3.8 ka. Our results show that, while winter temperatures were cold throughout the region, precipitation amounts had a heterogeneous distribution, with regionally significant low values in W Asia, SE Europe, and N Europe and local high values in the N Balkan Peninsula, the Carpathian Mountains, and E and NE Europe. Further, strong northerly winds were dominating in the Middle East and E and NE Europe. Analyzing the relationships between these climatic conditions, we hypothesize that in the extratropical Northern Hemisphere, the 4.2 ka BP event was caused by the strengthening and expansion of the Siberian High, which effectively blocked the moisture-carrying westerlies from reaching W Asia and enhanced outbreaks of cold and dry winds in that region. The behavior of the winter and summer monsoons suggests that when parts of Asia and Europe were experiencing winter droughts, SE Asia was experiencing similar summer droughts, resulting from failed and/or reduced monsoons. Thus, while in the extratropical regions of Eurasia the 4.2 ka BP event was a century-scale winter phenomenon, in the monsoon-dominated regions it may have been a feature of summer climate conditions.

Evaluation of the productivity of the hybrid vine Seyval blanc in function of several types of protection against frost in Quebec

OENO One ◽  
2003 ◽  
Vol 37 (1) ◽  
pp. 1
Author(s):  
T. Telebak ◽  
Yvon Jolivet ◽  
Jean-Marie Dubois
Keyword(s):  
Mortality Rate ◽  
Snow Cover ◽  
Sugar Content ◽  
Winter Season ◽  
Ambient Air ◽  
Bare Soil ◽  
Climatic Conditions ◽  
The Other ◽  
Potential Yield ◽  
Natural Snow

<p style="text-align: justify;">In Quebec, winter frost is one of the determining factors influencing vine survival and yield. To evaluate the quality of the different types of winter protection, ground temperature data under different covers (ground knolls, leaf mounds, carried over snow and natural snow) and ambient air temperatures were recorded. Results show that the Seyval blanc, if not protected against winter frost, can sustain quite serious damages when the air temperature reaches -30 °C. Ridging, leaf covering and the natural snow cover as well as carried over snow have a positive effect on ground temperatures, since over the site without protection, frost penetrated down to a depth of 50 cm. However, it seems that the root System did not sustain significant damages from the ground frost since regrowth occurred in the Spring. Because of its direct exposure to radiation and surface climatic conditions, bare soil warms up more quickly in the Spring compared to the other sites benefiting from protection. Results also indicate that the mortality rate of the vine stock fruit buds without protection is nearly 100 % compared to the protected vine stocks with a fruit bud mortality rate varying from 22.5 to 35.8 %. The protected vine stocks, regardless of the type of protection used, had satislactory yields from 7.2 t/ha to 24.4 t/ha. On the other hand, the raisin yield of the vine stocks without any winter protection is null. The best raisin yields were obtained over sites where vine stocks were protected by ridging (40 cm of earth), while the vine stocks protected by leaf covering showed an average yield. We also observed that when vine stock leaf covering is coupled with lodged vine shoots, raisin yields are higher than when the vine shoots are erect. However, in both cases, potential yield per hectare is satisfactory. Hence, the lodging of vine shoots becomes a useless operation. The vine stocks protected by natural snow as well as by leaf covering (30 cm + carried over snow and lodged vine shoots) gave the fruit with the highest sugar content. Snow is also an excellent insulator because a 37 cm high snow cover permitted the survival of the vine stocks protected by snow even when the temperature reached -30 °C. The only problem still posing a threat is snow cover variability during the winter season. A reduced snow cover, coupled with temperature conditions under the threshold of tolerance of the vine to cold, could not insure satisfactory protection ol the fruit buds.</p>

European vegetation during Marine Oxygen Isotope Stage-3

2003 ◽  
Vol 59 (2) ◽  
pp. 195-212 ◽  
Author(s):  
Brian Huntley ◽  
Mary Jo Alfano ◽  
Judy R.M Allen ◽  
Dave Pollard ◽  
Polychronis C Tzedakis ◽  
...  
Keyword(s):  
Climate Model ◽  
Global Climate ◽  
Analytical Data ◽  
Winter Season ◽  
Climatic Conditions ◽  
Sensitivity Analyses ◽  
Climate Feedback ◽  
Vegetation Model ◽  
Oxygen Isotope Stage ◽  
Simulated Climate

AbstractEuropean vegetation during representative “warm” and “cold” intervals of stage-3 was inferred from pollen analytical data. The inferred vegetation differs in character and spatial pattern from that of both fully glacial and fully interglacial conditions and exhibits contrasts between warm and cold intervals, consistent with other evidence for stage-3 palaeoenvironmental fluctuations. European vegetation thus appears to have been an integral component of millennial environmental fluctuations during stage-3; vegetation responded to this scale of environmental change and through feedback mechanisms may have had effects upon the environment. The pollen-inferred vegetation was compared with vegetation simulated using the BIOME 3.5 vegetation model for climatic conditions simulated using a regional climate model (RegCM2) nested within a coupled global climate and vegetation model (GENESIS-BIOME). Despite some discrepancies in detail, both approaches capture the principal features of the present vegetation of Europe. The simulated vegetation for stage-3 differs markedly from that inferred from pollen analytical data, implying substantial discrepancy between the simulated climate and that actually prevailing. Sensitivity analyses indicate that the simulated climate is too warm and probably has too short a winter season. These discrepancies may reflect incorrect specification of sea surface temperature or sea-ice conditions and may be exacerbated by vegetation–climate feedback in the coupled global model.

Thermal Modeling of a Rooftop Photovoltaic/Thermal System With Earth Air Heat Exchanger for Combined Power and Space Heating

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Sanjeev Jakhar ◽  
Manoj S. Soni ◽  
Robert F. Boehm
Keyword(s):  
Renewable Energy ◽  
Heat Exchanger ◽  
Las Vegas ◽  
Renewable Energy Sources ◽  
Winter Season ◽  
Climatic Conditions ◽  
Heating Capacity ◽  
Photovoltaic Thermal System ◽  
Maximum Cell ◽  
Useful Heat

Earth air heat exchanger (EAHE) systems are inefficient to provide thermal comfort in winter season for semi-arid regions. The performance of such systems could be improved by coupling them with other renewable energy sources. One of the renewable energy technology is rooftop photovoltaic/thermal (PV/T) air collectors which could utilize the incident solar insolation to obtain both electricity as well as useful heat. In the current paper, the thermal performance of an EAHE coupled with a PV/T system has been numerically investigated for climatic conditions of Pilani, Ajmer (India), and Las Vegas (U.S.). For the comparative analysis, a thermodynamic model has been developed and compared with experimental data available in the literature which seems to be in good comparison with the results. Further, a parametric analysis has been carried out for assessing the effect of different operating parameters. Results showed that for the winter season, the maximum cell temperature without any cooling goes up to 54.3 °C, 54.5 °C, and 44.4 °C for Pilani, Ajmer, and Las Vegas, respectively, while with cooling it drops to 43.4 °C, 44.2 °C, and 35.6 °C, respectively, for 0.053 kg/s flow rate. The heating capacity of the EAHE was observed to be improved with PV/T air collector by 23.47 Wh–298.74 Wh, 71.18 Wh–315.93 Wh, and 41.43 Wh–270.75 Wh for the Pilani, Ajmer, and Las Vegas, respectively.

scholarly journals Influence of Vermicompost as the Source of Nitrogen in Various Combinations with Chemical Fertiliser on Winter Wheat Productivity

2021 ◽  
Vol 16 ◽  
pp. 1-9
Author(s):  
Sruti Karmakar ◽  
Deepak Kashyap
Keyword(s):  
Agricultural Land ◽  
Arid Zone ◽  
Block Design ◽  
Winter Season ◽  
Climatic Conditions ◽  
Growth And Yield ◽  
Wheat Crop ◽  
Plant Laboratory ◽  
Semi Arid ◽  
Chemical Fertiliser

There is rarely any study that deals with the application of vermicompost in combination with chemical fertiliser to study the growth and yield variables of wheat crop in the typical agro-climatic conditions of saline sandy agricultural land of tropical semi-arid climatic condition with vast fluctuations of temperature between summer and winter seasons. Hence, the current study has been planned with a broader objective of utilising the organic resources by preparing vermicompost and applying it as the partial substitute of chemical fertiliser to cultivate wheat in an eco-friendly manner in saline sandy agricultural land of the tropical semi-arid zone. For achieving the intended goal, an experiment was conducted in the field of ‘Soil-Water-Plant Laboratory’, Department of Civil Engineering, IIT Ropar, Punjab, India during the winter season (rabi) of 2018-19. In this experiment, Randomised Block Design (RBD) was followed, and four treatments were used, including T1: 100% RD using chemical fertilisers, T2: 50% RD using chemical fertilisers + 50% of nitrogen through vermicompost, T3:75% RD using chemical fertilisers + 25% of nitrogen through vermicompost and T4: control (without any additional nutrients). Each treatment was replicated nine times. Plot size was 4m × 6m, and row to row spacing was 0.2 m. Following statistical analysis, it was found that treatment T2 (50% RD using chemical fertilisers + 50% of nitrogen through vermicompost) showed the best results, which were reflected in different parameters such as number of effective tillers per plant, ear length, number of grains per ear, and test weight, grain yield and straw yield of the wheat crop in comparison to other treatments. In this case, an almost equal amount of nitrogen supply from both organic and inorganic sources is responsible for getting the best results.

scholarly journals Performance analysis of a solar-assisted ground source heat pump system in climatic conditions of Turkey

2020 ◽  
Vol 24 (2 Part A) ◽  
pp. 977-989
Author(s):  
Salih Coskun
Keyword(s):  
Power Consumption ◽  
Heat Pump ◽  
Winter Season ◽  
Climatic Conditions ◽  
Cold Climate ◽  
Hot Water ◽  
Ground Source Heat Pump ◽  
Pump System ◽  
Heat Pump System ◽  
Ground Source

In order to contribute to widespread use of RES in Turkey, a solar-assisted ground source heat pump system was modeled using TRNSYS software and simulated for heating and supplying daily hot water to meet the needs of a restaurant in five sample provinces having different climatic conditions. During the simulation, the dining room temperature of the restaurant was kept constant at 22?C during the winter season and a total of 300 Lph of water (55?C) was used for 15 minutes four times a day. According to the simulation results, power consumption rates in the solar-assisted ground source heat pump system were determined as about 60% for the heat pump, 16% for heaters, 14% for the ground pump and 8% for fans and other pumps. The highest power consumption, as expected, was obtained for Hakkari Province (6723 kW) in the Eastern Anatolia region, which has a cold climate, while the lowest power consumption was obtained for Izmir Province (2822 kW) in the Aegean region, which has mild climatic conditions. The lowest seasonal performance factor and solar factor values were calculated as 2.27 and 32% for Hakkari and the highest as 2.71 and 56% for Izmir, respectively.

scholarly journals Raising Climate-Resilient Embolden Rice (Oryza sativa L.) Seedlings during the Cool Season through Various Types of Nursery Bed Management

2021 ◽  
Vol 13 (22) ◽  
pp. 12910
Author(s):  
Mousumi Mondal ◽  
Benukar Biswas ◽  
Sourav Garai ◽  
Saju Adhikary ◽  
Prasanta Kumar Bandyopadhyay ◽  
...  
Keyword(s):  
Management Practices ◽  
Field Experiments ◽  
Oryza Sativa L ◽  
Winter Season ◽  
Biochemical Properties ◽  
Climatic Conditions ◽  
Central Research ◽  
Seedling Production ◽  
Root Characteristics ◽  
Potential Yield

Facing cold stress is amajor constraint in seedling production during the winter season as, most particularly in recent times due to uncertain climatic conditions, no sustainable technology has been reported that could be easily adopted by farmers withlimited resources. Therefore, field experiments were carried out during winter 2017–2018 and 2018–2019 at the Central Research Farm of Bidhan Chandra KrishiViswavidyalaya, West Bengal, India to study the growth, survival potential, yield and nutritional and biochemical properties of boro rice seedlings as influenced by two seedbed management practices viz. conventional seedbed (farmers’ practice) and improved seedbed (polythene protected with micronutrient supplementation). The major objective was to lower the nurserybed duration without compromising seedlings’ health and to studythe economic viability during the winter season. The experiment was laid out in ten experimental units and deployed anindependent-sample t-test to compare the performance of the seedlings. The microclimatic changes were also itemized from both seedbeds. The seeds sownunder improved nursery conditions resulted in better seedling emergence (~90%) and survival percentage (~85%) as compared to the conventional seedbed (~70% and 65%). Growth attributes in terms of plant height, biomass accumulation, root characteristics, tiller count, and growth rate were observed to be better from the polythene-protected nursery bed. Theimproved nursery bed accounted for 20% higher seedling count at the time of transplantation over the conventional bed. The microclimatic situation under a polythene covering was also favorable for germination and seedling growth. Maximum nutrient (N, P, and K) concentrations, as well as chlorophyll content, wererecorded from improved seedlings. Results suggested that the improved seedbed management was apotential alternative toearly embolden seedling production during the winter to avoid climatic abnormalities. Most importantly, improved seedbeds ensured a comprehensive route from germination to healthy seedling production without any failure in thesmalltime window, which involvedless input as well as cost involvement. This technique could diffusethe problem oflate sowing conditions in the rice–rice cropping system.

Casazeroenergy: An Italian Prototype of Zero Energy Building

2013 ◽  
Vol 38 (3) ◽  
pp. 25-30
Author(s):  
Antonio Frattari
Keyword(s):  
Natural Ventilation ◽  
Cooling System ◽  
Winter Season ◽  
Heat Pumps ◽  
Climatic Conditions ◽  
Geothermal System ◽  
Geothermal Heat ◽  
Renewable Sources ◽  
Zero Energy Building ◽  
Natural Building

CasaZeroEnergy is the prototype for a building that does not use energy produced from non-renewable sources, but produces its require energy by using alternative energetic systems. Designed according to the principles of bioclimatic architecture, the building was integrated with passive systems for optimizing the site's climatic conditions for heating in winter and for cooling and ventilation in summer. The house was constructed with natural, renewable, recycled and recyclable materials. For this reason it can be classified as a “natural building”. Its main feature is the integration between the building and the alternative systems in order to produce energy from renewable sources: sunspace, solar collectors, photovoltaic panels, a geothermal system and a pellet boiler system. Home automation manages all the mechanical systems to ensure comfort and reduced energy consumption at the same time. The sunspace is a passive solar system used mainly for heating indoor spaces during the winter season. The building's cooling system is based on natural ventilation strategies and on geothermal heat pumps. The building is provided with shading systems. A smart system was devised to guarantee user safety and security. This kind of system can be controlled remotely and provides constant security for the building.

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