Orchard Planting Density and Tree Development Stage Affects Physiological Processes of Apple (Malus domestica Borkh.) Tree

One of the most important factors affecting photosynthesis and metabolism is light absorbance by leaves and penetration through the canopy. The aim of this study was to evaluate the influence of planting density and tree development stages on photosynthetic activity, photosynthetic pigments, and carbohydrates in apple (Malus domestica Borkh.) trees in a combined way. The apple tree, Auksis, was grafted on dwarfing rootstock P 22. Space between rows was 3 m, trees were planted in 2001 in four distances: 0.25 m, 0.50 m, 0.75 m, and 1.00 m. Measurements and leaf samples were taken in the end of May (leaves fully expanded BBCH 20–25), in the middle of July (beginning of apple maturity BBCH 73–75) and at the end of August (harvest time BBCH 87–88) according BBCH—growth stages. Photosynthetic rate was significantly the lowest in the spring and tended to rise until fruit ripening, when it increased up to 19.4% compared to spring. Significantly the highest chlorophyll b and carotene α and β contents were found at the BBCH 73–75. The lowest levels of fructose and sorbitol in leaves were found at BBCH 73–75. The amount of starch accumulated in the leaves increased three times in summer compared to spring. Reduced distance between trees to four times (from 1 m to 0.25 m) showed clear competitive stress, as the decrease of photosynthetic rate (up to 36.4–38.6%) and total starch (up to 37–53%) was observed. The photosynthetic behaviour of apple trees was significantly affected by the development stage during the particular season which is related with physiological changes of metabolites transport and their distribution during fruit ripening and leaf senescence.publishedVersio

Orchard Planting Density and Tree Development Stage Affects Physiological Processes of Apple (Malus domestica Borkh.) Tree

One of the most important factors affecting photosynthesis and metabolism is light absorbance by leaves and penetration through the canopy. The aim of this study was to evaluate the influence of planting density and tree development stages on photosynthetic activity, photosynthetic pigments, and carbohydrates in apple (Malus domestica Borkh.) trees in a combined way. The apple tree, Auksis, was grafted on dwarfing rootstock P 22. Space between rows was 3 m, trees were planted in 2001 in four distances: 0.25 m, 0.50 m, 0.75 m, and 1.00 m. Measurements and leaf samples were taken in the end of May (leaves fully expanded BBCH 20–25), in the middle of July (beginning of apple maturity BBCH 73–75) and at the end of August (harvest time BBCH 87–88) according BBCH—growth stages. Photosynthetic rate was significantly the lowest in the spring and tended to rise until fruit ripening, when it increased up to 19.4% compared to spring. Significantly the highest chlorophyll b and carotene α and β contents were found at the BBCH 73–75. The lowest levels of fructose and sorbitol in leaves were found at BBCH 73–75. The amount of starch accumulated in the leaves increased three times in summer compared to spring. Reduced distance between trees to four times (from 1 m to 0.25 m) showed clear competitive stress, as the decrease of photosynthetic rate (up to 36.4–38.6%) and total starch (up to 37–53%) was observed. The photosynthetic behaviour of apple trees was significantly affected by the development stage during the particular season which is related with physiological changes of metabolites transport and their distribution during fruit ripening and leaf senescence

Dynamical Study of Heat Transport Properties of Porous Silicon

A new technique to determine thermal conductivity of porous silicon is proposed. Transient thermoelectric voltage is measured after a pulsed laser irradiation, and knowledge of the voltage decay time constant and porosity of the structure gives the value of the thermal conductivity. For n-type Si of 70% porosity we show the value of 35 W m-1 K-1. The method can be easily applied for any other porous or otherwise structured low-dimensional media.DOI: http://dx.doi.org/10.5755/j01.ms.21.2.5785</p

Wpływ jakości CO₂ na młodą sałatę uprawianą pod zoptymalizowanym spektrum światła

The cost and yield are two the most important criteria in agriculture by which optimization of environmental factors are needed to carry out. In the present study, we investigated the efficient lighting spectrum and elevated CO2 concentration for cultivating healthier plants more rapidly. One of the aims of our study is to optimize LEDs light spectrum for healthier vegetable production in greenhouses and maximum economical benefits for growers. The impact of elevated carbon dioxide (CO2) concentration on antioxidant and nutritional properties of green leaf ‘Multigreen 3’ and red leaf ‘Multired 4’ baby leaf lettuce (Lactuca sativa L.), grown under optimized light spectrum was investigated. CO2 concentrations of 0.963 g · dm-3and 1.938 g · dm-3 were maintained in the growth chambers. Lettuce was grown under four wavelength (640, 455, 660 and 735 nm) light-emitting diode based (LED) illumination. Under 0.963 g · dm-3 CO2 conditions, ‘Multired 4’ lettuce represented higher antioxidant value due to higher ascorbic acid, anthocyanin, tocopherol contents and higher sucrose concentration, as compared to ‘Multigreen 3’ lettuce. Higher CO2 concentration (1.938 g · dm-3) had uneven effect on the quality of both baby leaf lettuce cultivars. Red leaf lettuce reacted to the higher CO2 level by lowered D tocopherol, ascorbic acid concentrations and significantly higher glucose contents in their leaves, when green leaf lettuce – contrarily – contained higher ascorbic acid and D tocopherol concentrations under 1.938 g · dm-3 of CO2.Koszty i plon to dwa najważniejsze kryteria w rolnictwie, według których należy wybierać optymalne czynniki środowiska. W niniejszym badaniu oceniano spektrum światła i podwyższone stężenie CO2 w celu szybszej hodowli zdrowych roślin. Jednym z celów badania było zoptymalizowanie spektrum światła LED w celu produkcji zdrowszych warzyw w cieplarniach oraz dla maksymalnych korzyści ekonomicznych hodowców. Badano wpływ podwyższonego stężenia dwutlenku węgla (CO2) na cechy anytoksydacyjne i żywieniowe młodej sałaty zielonej ‘Multigreen 3’ i czerwonej ‘Multired 4’ (Lactuca sativa L.) hodowanych w warunkach zoptymalizowanego spektrum światła. W komorach wzrostu utrzymywano stężenia CO2 wynoszące 0,963 g · dm-3 oraz 1,938 g · dm-3. Sałata wzrastała oświetlana diodą emitującą światło (LED) o czterech długościach fal (640, 455, 660 i 735 nm). W warunkach 0,963 g · dm-3 CO2 sałata ‘Multired 4’ miara większą wartość antyoksydacyjną ze względu na wyższy poziom kwasu askorbinowego, antocyjanin, tokoferolu oraz wyższe stężenie sacharozy w porównaniu z sałatą ‘Multigreen 3’. Wyższe stężenie CO2 (1,938 g · dm-3) miało nierówny wpływ na jakości obu odmian sałaty. Sałata czerwona reagowała na wyższy poziom CO2 obniżonym Į-tokoferolem i stężeniem kwasu askorbinowego oraz istotnie wyższą zawartością glukozy w liściach, natomiast zielona sałata miała wyższe stężenie kwasu askorbinowego i Į-tokoferolu w warunkach 1,938 g · dm-3 of CO2