Lower Thermal Requirements Research Articles

ВОЗДЕЛЫВАНИЕ СЕЛЬСКОХОЗЯЙСТВЕННЫХ КУЛЬТУР В УСЛОВИЯХ ПОНИЖЕННЫХ ТЕМПЕРАТУР

Humanity at the present stage of development has already faced the consequences of its economic activities, which has caused global changes in the world around it. Climate change on our planet is observed in all regions. As is known, this period is geologically anthropogenic, which is characterized by alternating glaciations. The main development and implementation of the country's food security program is the creation of a sustainable food supply. And also, the growth of livestock production in line with population growth. Corn is widely distributed in the world due to its high productivity and nutritional value, as well as its ability to adapt to different climatic zones. Corn is a crop sensitive to cold, and it has a serious delay in growth and development when exposed to sudden cold spells in the early period of growth and development. For the successful promotion of this crop to more northern regions, it is necessary to include hybrids with low thermal requirements in agricultural production. It is also equally important to create favorable conditions for plants in new regions. The purpose of the research was to build a dynamic model of corn cultivation at low temperatures due to climate change at the global level. The main area of research was to identify the possibility of normal functioning of corn in conditions of low temperatures. The first experiment (2004-2007) was aimed at a comparative study of various subspecies and varieties of corn to identify morphobiological factors of adaptation process management. In the second experiment (2012-2013), the subject of the study was the effect of various drugs, including derivatives of indolylacetic acid, and the timing of crop sowing on its productivity. Thus, the morphobiological, agrotechnical and microbiological issues of increasing the cold resistance of corn as the main food and feed crop have been studied. The influence of the studied factors on the growth processes and yield of green mass has been determined.

Seed Dormancy and Soil Seed Bank of the Two Alpine Primula Species in the Hengduan Mountains of Southwest China.

The timing of germination has long been recognized as a key seedling survival strategy for plants in highly variable alpine environments. Seed dormancy and germination mechanisms are important factors that determining the timing of germination. To gain an understanding of how these mechanisms help to synchronize the germination event to the beginning of the growing season in two of the most popular Primula species (P. secundiflora and P. sikkimensis) in the Hengduan Mountains, Southwest China, we explored their seed dormancy and germination characteristics in the laboratory and their soil seed bank type in the field. Germination was first tested using fresh seeds at two alternating temperatures (15/5 and 25/15°C) and five constant temperatures (5, 10, 15, 20, and 25°C) in light and dark, and again after dry after-ripening at room temperature for 6 months. Germination tests were also conducted at a range of temperatures (5–30, 25/15, and 15/5°C) in light and dark for seeds dry cold stored at 4°C for 4 years, after which they were incubated under the above-mentioned incubation conditions after different periods (4 and 8 weeks) of cold stratification. Base temperatures (T b) and thermal times for 50% germination (θ 50) were calculated. Seeds were buried at the collection site to test persistence in the soil for 5 years. Dry storage improved germination significantly, as compared with fresh seeds, suggesting after-ripening released physiological dormancy (PD); however, it was not sufficient to break dormancy. Cold stratification released PD completely after dry storage, increasing final germination, and widening the temperature range from medium to both high and low; moreover, the T b and θ 50 for germination decreased. Fresh seeds had a light requirement for germination, facilitating formation of a persistent soil seed bank. Although the requirement reduced during treatments for dormancy release or at lower alternating temperatures (15/5°C), a high proportion of viable seeds did not germinate even after 5 years of burial, showing that the seeds of these two species could cycle back to dormancy if the conditions were unfavorable during spring. In this study, fresh seeds of the two Primula species exhibited type 3 non-deep physiological dormancy and required light for germination. After dormancy release, they had a low thermal requirement for germination control, as well as rapid seed germination in spring and at/near the soil surface from the soil seed bank. Such dormancy and germination mechanisms reflect a germination strategy of these two Primula species, adapted to the same alpine environments.

Phenology and thermal requirements of disease-resistant genotypes (PIWI) grown in the Goethe Grape Valley region of Brazil

The Goethe Grape Valley (GGV) is a traditional southern Brazilian region for grape and wine production, mainly planted with hybrid vines. High temperatures and rainfall conditions hamper the cultivation of Vitis vinifera cultivars susceptible to disease, especially Plasmopara viticola. New PIWI (from the German word ‘Pilzwiderstandsfahige’) genotypes of V. vinifera with resistance to P. viticola are under evaluation in this region. The aim of this work was to characterize the phenology and thermal requirements of PIWI genotypes grown in the GGV. The experiment was carried out in an experimental vineyard (28°32’S 49°19’W, altitude 60 m a.s.l.), established in 2016, and evaluations were done for the 2018 vintage. The evaluated PIWI cultivars were ‘Aromera’, ‘Baron’, ‘Calardis blanc’ and ‘Felicia’. Minimum and maximum air temperatures were recorded daily, using 10°C as the low temperature threshold, 25°C as the optimum temperature for development, and 35°C as the upper temperature threshold of development. The evaluated phenological stages were budbreak to flowering, flowering to veraison and veraison to maturity. The total thermal requirement mean was 1360°C day; ‘Felicia’ showed the lowest thermal requirement (1260°C day), which contrasted with ‘Aromera’, which presented the highest thermal requirement (1454°C day). ‘Baron’ and ‘Calardis blanc’ needed 1337 and 1391°C day, respectively, to reach maturity. From budbreak to flowering, the average thermal requirement was 229°C day, from flowering to veraison the mean was 679°C day, and from veraison to maturity the mean was 452°C day. The four evaluated cultivars exhibited adaptive development in the field with thermal requirements compatible with the region of GGV. The results also revealed the lower thermal requirement, and consequently shorter cycle, for ‘Felicia’, as well as the greater thermal requirement of ‘Aromera’.

Phenology and thermal requirements of grapevine cultivars in Dois Vizinhos, Paraná State, Brazil

ABSTRACT: This study aimed to characterize the phenology and thermal requirements of grapevine cultivars Bordô, BRS Carmem, BRS Lorena, BRS Magna, BRS Rubea, BRS Violeta, Concord, Concord Clone 30, Isabel, Isabel Precoce, Moscato Bailey, Moscato Embrapa, Niagara Branca, Niagara Rosada, and Seibel 5455 grafted on Paulsen 1103. The study was conducted in the fruit growing sector of the Federal Technological University of Paraná, Câmpus Dois Vizinhos, Paraná State, Brazil, during the cycles of 2015/2016 and 2016/2017. The experimental design was completely randomized, with four replicates and two evaluated plants per plot. Plants were grown in a vertical trellis system and spur pruned with two buds. Evaluations of phenology and thermal requirements were carried out from pruning to harvest. Cultivars Moscato Bailey and Seibel 5455 had high thermal requirements and longer cycles, while cultivars BRS Magna, BRS Violeta, and Isabel Precoce had lower thermal requirements and shorter cycles. The cycle and the thermal requirements of cultivars ranged from 98 to 132 days, and from 1065 to 1548 degree-days, respectively.

Cardinal temperatures and thermal requirements for the initial development of two Brazilian native species

Abstract: The objective of this work was to estimate the cardinal temperatures and to quantify the thermal requirements for the initial development of seedlings of the native tree species Citharexylum myrianthum and Bixa orellana. A field experiment was carried out in a completely randomized design, in a 2?12 factorial arrangement (2 tree species and 12 sowing dates), with five replicates. The base, optimum, and maximum temperatures for the development of C. myrianthum were 11.4, 18.1, and 36.6°C, and, for B. orellana, 12.0, 18.4, and 46.4°C. The thermal requirements for the development of C. myrianthum was 66.7°C day per leaf, and, for B. orellana, 82.5°C day per leaf. In the initial development, B. orellana shows a large thermal amplitude and is tolerant to extreme temperatures, while C. myrianthum shows a large thermal amplitude, but a lower thermal requirement and a more rapid development than B. orellana.

From Hydrindane to Decalin: A Mild Transformation through a Dyotropic Ring Expansion.

An unexpected ring expansion converting hydrindane cores into decalins has been observed. The process occurs under very mild conditions and with exquisite transfer of chiral information. The ring expansion provides access to decorated decalins with complete stereocontrol. The reaction mechanism is studied in order to gain insight into the underlying causes for the low thermal requirements in this reaction and the nature of the chirality transfer process. Interestingly, both result from an unprecedented dyotropic reaction involving a mesylate group.

Energy consumption and optimization of internally cooled/heated liquid desiccant air-conditioning system: A case study in Hong Kong

LDAC (liquid desiccant air-conditioning system) is promising for reducing the energy consumption, and improving the indoor air quality. In this paper, the operation performance of LDAC with internally cooled/heated dehumidifier/regenerator was simulated and optimized. The cooling tower and solar collectors were employed as the cooling/heating source. Four nested iteration loops were developed and solved for system modeling. A typical commercial building in Hong Kong was selected as a case study, which air-conditioning load was obtained by Energy-plus. Results show that with the increase of solar collector area, the electricity consumption of AC (air-conditioning systems) system reduced by 11–35% in original system, but only a part of dehumidification demand was handled with liquid desiccant ventilation, which led to a low chiller COP (coefficient of performance). By adding a cooling coil for the solution entering dehumidifier, the electricity saving effectively increased to 22–47%, while the heat demand for regeneration also increased by 17%. So, a heat exchanger between water leaving regenerator and solution leaving dehumidifier was introduced. With the lower thermal requirement (reduced by 20%) and higher solar fraction (increased from 30 to 40%), the saving further increased to 29–49%, and the required collector area obviously reduced by 50–60% for the similar energy saving purpose.

Low-temperature deposition of ultrathin SiO2 films on Si substrates

We present a detailed investigation of the properties of silicon dioxide deposited at a low temperature. The advantages of this process include its low thermal requirements (about 200 °C), the absence of corrosive by-products and the lack of need of vacuum equipment. Sol solutions were prepared for the deposition of ultrathin SiO2 films by spin-coating at the low annealing temperature of 200 °C. The layers' thickness was 24 nm and 5 nm. We describe in detail the material properties of this novel low-temperature SiO2 layers obtained by extensive characterization using Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), XPS spectroscopy, capacitance-voltage (C-V) and current-voltage (I-V) measurements. The ultrathin oxide layers on Si substrates show good dielectric properties.

Local differentiation of flowering phenology in an alpine-snowbed herb Gentiana nipponica

Phenological events of alpine plants are strongly influenced by the seasonal thermal conditions at the local scale that are caused by heterogeneity in snowmelt time. Populations in late-snowmelt locations suffer from a short period for seed maturation, in which rapid flowering that occurs soon after snowmelt (i.e., a low thermal requirement for flowering) is advantageous. To test the possibility of local adaptation of flowering phenology, we compared reproductive phenology, the preflowering period, and the thermal requirement for flowering of the alpine-snowbed species Gentiana nipponica Maxim. between populations inhabiting early- and late-snowmelt sites within a local area. Plants in the late-snowmelt population showed a shorter preflowering period than in the early-snowmelt population; nevertheless, they often failed to set fruit owing to the short growth period. To test the plasticity and genetic regulation of flowering phenology, we performed a reciprocal transplant experiment between early- and late-snowmelt populations. Although the preflowering period showed clear plastic responses depending on the transplanted habitats, the lower thermal requirement for flowering was retained in plants originating from the late-snowmelt populations, even after transplantation. Therefore, habitat-specific differentiation of flowering phenology was genetically determined between these local populations.

Living with your food: geckos in termitaria of Cantão

AbstractWe tested three non‐exclusive hypotheses that the lizard, Gymnodactylus carvalhoi, lives in termitaria to avoid thermal extremes, to avoid predators, or because of an abundance of food (dietary specialist). We first confirm that these geckos are restricted to termitaria in the region studied. Body temperatures (Tb) of geckos averaged below environmental temperatures during day outside of termitaria and above outside temperatures at night; Tb averaged only slightly higher than temperatures inside termitaria. We conclude that thermal constraints in Cerrado habitats lacking rocks restrict Gymnodactylus to termite nests. High frequencies of tail loss and the presence of many potential predators within termitaria suggest high encounter rates with predators, indicating that predation pressure does not restrict these geckos to termite nests. Dietary data indicate that G. carvalhoi is a termite specialist. Published data indicate that other Gymnodactylus species and populations are also termite specialists, even though several live primarily outside termitaria (in crevices and under rocks). An evolutionary history of termite specialization and low thermal requirements in the clade (Gymnodactylus) predispose them to feed on termites within the termitaria.

Thermal Requirements and Parasitism Capacity of Trissolcus brochymenae (Ashmead) (Hymenoptera: Scelionidae) Under Constant and Fluctuating Temperatures, and Assessment of Development in Field Conditions

In order to understand the relative importance of Trissolcus brochymenae , a common egg parasitoid of the predatory stinkbug Podisus nigrispinus in areas where this predator is released, the thermal requirements and developmental periods (egg to adult) at constant (17, 20, 25, 28 and 32°C) and fluctuating (10-20, 13-23, 15-25, 17-27, 20-30 and 25-35°C) temperatures, and the effect of constant and fluctuating temperatures systems on the longevity and parasitism capacity of T. brochymenae were investigated. Based on thermal requirements of the parasitoid and field day/night temperature variation in the regions where P. nigrispinus was released, we calculated monthly and yearly number of generations of the parasitoid. Parameters of biological and thermal requirements of T. brochymenae were not affected when the insects were reared under constant or fluctuating temperatures. It was shown that males have a shorter developmental period and lower thermal requirements than females. The lowest parasitism capacity and shortest longevity of T. brochymenae were observed under fluctuating temperature regimes of 10-20oC and 25-35°C. A higher parasitism capacity was obtained under a 20-30°C regime (96.0 - 33.6 offspring per female), while longevity was longer at a constant temperature of 27°C (17.6 - 0.6 days). T. brochymenae showed a continuous development during all seasons through the year under field conditions, accomplishing 2.7, 2.4, 2.9 generations per month in the CAF, Pains, and Refloralje areas. An average of 26.4 and 25.8, 25.8 and 25.3, and 24.7 and 23.6 generations per year under constant and fluctuating temperatures systems was estimated for the CAF, Pains, and Refloralje areas, respectively. No significant difference between thermal systems in each area was observed; however, a significantly smaller number of generations per year were estimated to occur in the Refloralje area. Implications of these results for the forecasting of parasitoid population development and its impact on the host stinkbug predator are discussed.