THE INFLUENCE OF CLIMATIC FACTORS AND TECHNOLOGY IN SOME POTATO VARIETIES GROWN ON SANDY SOILS

Less favorable conditions on sandy soils in southern Oltenia limited number ofspecies and varieties grown in the area. Drought and high temperatures in recent years (maximum 430 C in air, ground 700 C) acted as dehydrating forces on plants, disrupting their metabolism.Very high air temperature in July and August at 30 to 38.40 C relative humidity decreased to 25%, high soil surface temperature and lack of rainfall during the growing season, producing an imbalance of the water balance of plants.Excessive sweating can dehydrate plants leaf level, close osteolele and diminish gasexchange in photosynthesis

Research on the activity of some oxidative enzymes from potato leaves

Oxidative enzymes catalyze the decomposition of reactive oxygen species: hydrogen peroxide, superoxide, hydroxyl and singlet oxygen, which are formed during the normal plant physiological processes. The hydrogen peroxide is decomposed by peroxidase and catalase along with superoxide dismutase. This research studies the activity of those enzymes in potato leaves from plants subjected to thermo-hydric stress. The activity of oxidative enzymes studied had a similar dynamic in the potato leaves. The highest activity was determined during budding phase, in which the leaves are most sensitive to the action of thermo-hydric stress. All three enzymes analyzed had increased activity in the leaves of plants grown at a 50% AHI hydric regime compared with those from the variants grown at 80% AHI regime. Under thermo-hydric stress conditions the highest activity of catalase, peroxidase and superoxide dismutase was determined in Robusta variety, which proved to be more sensitive to the action of these factors, and the lowest activity of those enzymes was determined for Sante and Tresor varieties

Dynamics of tubers' accumulation and the nutritional quality of the potatoes cultivated on the sandy soils from the South plain area from Romania

Potato production is very high performing culture, but also very demanding environmental conditions (climatic) and technological (fertilization, protection). Potato yields are influenced by a complex of biological factors, environmental and technological. The strongest factor limiting production is drought period from May to September, when training and intense accumulation of tubers that occurs with great frequency in all areas of the country's culture. Potato varieties tested in 2008-2010 to the Research-Development Station for the Culture of the Plants on the Sandys Soils Dăbuleni, Dolj County, Romania, regarding the dynamics of accumulation in tubers showed that the variety is an important factor in culture technology. Choosing the right variety of potato crop leads to success. To highlight the ability of potato cultivars to accumulate as early substances in tuber harvesting were done at 45 days of vegetation at 55 days after physiological maturity vegetation and potato plants. Production of tubers in the trade conditions of the area by plain ranged greatly depending on the variety grown and harvest time. Determinations on quantitative accumulation and nutritional quality of potato tubers were performed according to the variety and amount of fertilizer applied to sandy soils in climatic conditions in southern of Oltenia

RESULTS ON THE INFLUENCE SPACE NUTRITION ON GROWTH AND DEVELOPMENT OF SWEET POTATO PLANT UNDER SANDY SOILS IN SOUTHERN OLTENIA

Microclimate created in the psamo-pelitic soils in southern Oltenia, offers great conditions for growth and development of sweet potato (Ipomoea batatas) which is a thermophilic plant specific tropical and subtropical areas. The results obtained during 2013-2015 from Dabuleni, Development Research Center for Plants Crops on Sands, emphasizes productions between 19221 -21634 kg / ha, depending on the size space nutrition and variety cultivated. Those two factors in the study have significantly influenced the conduct from plant physiological processes. The highest value from plant photosynthesis rate (28.81 micromoles CO2 / m2 / s) was recorded at 11 am, at a density of 40,000 plants / ha, when sweet potato plant has lost through sweating about 5.69 millimoles H2O / m2 / s

Influence of some agrotechnical factors on physiological indices of potato grown on sandy soils

Less favorable conditions on sandy soils in southern Oltenia (Romania) limited number of species and varieties grown in the area. Drought and high temperatures in recent years have acted as forces dehydrated plants, disturbing their metabolism.Very high air temperature, relative humidity decreased to 25%, high surface temperature and lack of rainfall during the growing season, producing an imbalance of fluid balance in plante. Excessive foliar transpiration level can dehydrate plants, close osteoles and diminuted gas exchange in the process of photosynthesis. Irrigation plants can remove the stress factor action in the area, maintaining a positive fluid balance, that evaporated water is replaced by water traspiration administered by irrigation. On the sandy soils plant photosynthesis shows a depression at noon when the action is the maximum stress factors. Research early require selection of species with short growing season, to avoid atmospheric and soil drought in July and August. Potatoes meet these requirements, and research in the present study we aimed directing agrotechnical factors (variety, irrigation, fertilization) in order to obtain high yields and efficient, in economic terms

Research on thermo hydric stress effect on some early potato physiological processes

The main climatic factors that affect the metabolism of horticultural plants are high temperature, low precipitation (drought) and increased soil salinity, as a result of those. This research aimed to clarify key physiological changes in Solanum tuberosum L. plants exposed to thermo hydric stress compared to those grown under normal conditions. Potato plants grown on sandy soil in two active humidity interval (A.H.I.) 50% and 80% were analyzed. Water stress conditions (50% from AHI) reduced the average intensity of the photosynthesis process of the five varieties of potatoes with an average of 16%, compared with irrigated (80% AHI). Under water stress, the average intensity of respiration process of the five varieties was higher by 7.8% compared with the variants grown at soil moisture of 80% AHI. Water stress occurred in the case of the 50% AHI, caused inhibition of transpiration in all varieties. Thermo hydric stress had no net influence on leaf chlorophyll content. Tresor variety grown in water stress conditions (50% AHI) was characterized by the most intense metabolic activity, with the highest intensity of the processes of photosynthesis, respiration, transpiration and highest chlorophyll content in leaves