THE INFLUENCE OF PROTECTING METHOD ON PHYSIOLOGICAL INDICES AT CAPSICUM GROWN ON SANDY SOILS

Research conducted in the field of plant physiology aimed at monitoring physiological reactions under the influence of climatic and agrotechnical factors. Agrotechnical factors can lead in order to increase photosynthetic efficiency, which influence qualitative and quantitative the production of pepper grown on sandy soils. The methods used to protect contributed to achieving a different microclimate, with positive impact both on plant metabolism and the earliness and high production compared to control plants unprotected. The amount of water in the leaves recorded values between 84% at plants protected with mulch and 88% at plants protected with Agryl. The dried substance hasregistered values between 12% at plants protected with Agryl and 16% at plants protected with mulch. At plants protected with Agrylis ensuredan aeration and circulation of air currents, maintaining a maximum foliar humidity. The rate of photosynthesis in April registered high values at the protected plants, compared with the unprotected plants. Foliar hydration registered high values due to rainfalls, which ensured a good supply of water at this stage of vegetation. Leaf transpiration rate recorded high values in May at 12 o'clock, ranging from 7,41 to 11,84 mmol H2O/m2/s, pepper being a plant that consumes a large amount of water

BEHAVIOR OF SOME POTATO VARIETIES UNDER THE INFLUENCE OF THE THERMO-HYDRIC STRESS FACTORS SPECIFIC TO THE SANDY SOILS AREA

During the vegetation period, was analyzed the diurnal and seasonal variation of the physiological processes (the rate of photosynthesis and foliar transpiration) at 4 varieties and 2 lines of potato grown on sandy soils. The rate of photosynthesis showed a diurnal variation, being influenced by the active radiation in photosynthesis and air and soil humidity, as well as by the studied varieties and lines. In the tuber growth phase, the average of photosynthesis oscillated between 12,49μmol CO2/m2/s at the Castrum variety and 21,03 μmol CO2/m2/s at the L 15-1677/31. At this stage of vegetation, the L 15 line  was net detached of the other varieties, having a maximum photosynthesis which has positively influenced the production of tubers, recorded at 45 days after the emergence of plants (42,4 tons/ha). The high air temperature of 37,3 °C and the relative air humidity below 30% increased the evaporation of water through foliar transpiration at all varieties and lines studied. High values at the transpiration rate were recorded at 12-15 o'clock, when the action of stress factors was maximal, at the Sarmis variety (8,35mmol H2O/m2/s), and at line L 15-1677/31 (8,74 mmol H2O/m2/s)

REACTION OF SUNFLOWER GENOTYPES TO THERMAL STRESS CONDITIONS IN THE SANDY SOILS AREA OF SOUTHERN OLTENIA

The researches carried out during 2016-2017 at RDCSPS Dabuleni aimed at the behavior of biological sunflower material, created at NARDI Fundulea, under conditions of thermal water stress from the sandy soils in southern Oltenia. The results obtained at 109 sunflower genotypes underline the favorability of Romania's southern area for sunflower culture. It showed significantly distinct positive correlation between the rate of  photosynthesis in the plant, and photosynthetic active radiation (r = 0.282 **) as well as between foliar sweating rate and leaf surface temperature (0.412 **). The production was differentiated according to the genotype and the climatic conditions of the agricultural year, ranging from 2299-5180 kg / ha, with an average of 4307 kg / ha

RESEARCH ON THE PHYSIOLOGY OF SWEET POTATO PLANTS ACCORDING TO BIOLOGICAL MATERIAL AND CLIMATIC CONDITIONS IN THE AREA OF SANDY SOILS

Climate changes in recent years also had repercussions on physiological processes in plants, with varying degrees of adaptation to stress. The sandy soils area has a natural background favorable to a significant impact of drought on agricultural crops, forcing us to grow new plants that can more easily withstand the thermo-hydric stress. The research of the physiology laboratory of the Research - Development Center for Field Crops on Sandy Soils Dabuleni aimed at monitoring the physiological reactions on vegetation phenophases at 5 sweet potato genotypes cultivated on transparent mulch in the first decade of May (the first epoch) in order to determine their tolerance to characteristic thermo-hydric stress of the sandy soils area. Were determined in diurnal variation: photosynthesis, foliar transpiration, photosynthetic active radiation and temperature at leaf level, as well as water forms and leaf-dried substance. The results obtained revealed that sweet potato is a plant ho loves light and heat, tolerant to the thermo-hydric stress characteristic of sandy soils. Most of the studied varieties have efficiently used the evaporation of water through foliar transpiration found in the high photosynthetic yield throughout the vegetation period