Effect of LED light irradiation on morphology, chlorophyll content and photosynthetic activity of strawberry (Fragaria × ananassa DUCH.) cuttings

Manipulating the light characteristics with LEDs (light-emitting diodes) allows the regulation of various aspects of plant growth and development. The aim of the study was to investigate the effect of supplementary irradiation with LEDs emitting blue, red or far-red light on the growth, chlorophyll content, and photosynthetic activity of in vitro-derived plants of two strawberry cultivars with different photoperiod requirements, short-day cultivar ‘Elsanta’ and photoneutral cultivar ‘Selva’. Supplementary irradiation with blue light significantly affected the growth parameters of plants of the photoneutral strawberry ‘Selva’, but had no effect on the growth of ‘Elsanta’ plants. Exposure to blue light did not affect the chlorophyll content index (CCI) or the maximum efficiency of the photochemical reaction of photosystem II (Fv/Fm) of any strawberry cultivars. Red and far-red light supplementary irradiation did not significantly affect plant growth, but it improved the Fv/Fm parameter in both strawberry cultivars after 57 days of the experiment. Irradiation with red and far-red light inhibited the formation of runners, while blue light limited their development by 50%

Effect of LEDs lampson strawberry growth and development during ex vitro acclimatization

W doświadczeniu oceniano wpływ doświetlania lampami LED na rozwój mikrosadzonek truskawki podczas aklimatyzacji. Nieukorzenione mikrosadzonki odmiany „Pink Rosa” z laboratorium in vitro, oczyszczone z agaru. posadzono do multiplatów, do podłoża składającego się z wełny mineralnej chłonącej i niechłonacej (1:1). Rośliny uprawiano w kamerach wzrostowych zapewniając im wysoką wilgotność (80-90%), temperaturę 20-22°C oraz doświetlając je 16 godzin na dobę. Źródłem światła były: lampa sodowa 400 W (HPS), lampa LED – DAPLON-plus/2011 skonstruowana w Instytucie Elektrotechniki, emitująca światło w zakresach widmowych: czerwonym 68,5%, niebieskim 28,4% i bliskiej podczerwieni 3,1% (LED I) oraz lampa LED GrowBox emitująca światło czerwone i niebieskie 8:1 (LED II). Ze względu na wrażliwość mikrosadzonek początkowo rośliny cieniowano tak by natężenie napromienienia wynosiło 50 µmol m-2s-1, natomiast po 3 tygodniach zwiększono je do poziomu 100-120 µmol m-2s-1. Wszystkie rośliny nawożono identycznie płynną pożywką nawozową zawierającą makro i mikroskładniki. Wzrost i rozwój mikrosadzonek oceniono po 7 tygodniach aklimatyzacji. Zastosowane do doświetlania lampy LED wpłynęły bardzo korzystnie na wzrost mikrosadzonek truskawki. Mikrosadzonki doświetlanie lampami DAPLON-plus/2011 (LED I) miały największą świeżą masę, powierzchnię liści oraz najdłuższe korzenie. Nieznacznie słabiej rozwiniętą część nadziemną miały rośliny doświetlane drugim wariantem lamp, LED II. Rośliny doświetlane lampami LED wytworzyły więcej korzeni oraz miały grubsze szyjki korzeniowe niż doświetlanie lampami HPS.The effect of artificial lighting, using HPS and LED lamps during acclimatization of strawberry was evaluated. Unrooted strawberry plantlets ‘Pink Rosa’ obtained from in vitro laboratory were planted into growing media consisted of mineral wool granulates, water repellent and water absorbent (50:50 v/v). Plantlets were grown in growth chambers, with high humidity (80-90%), temp. 20-22°C and with artificial lighting using HPS (400 W) and LED lamps, photoperiod 16/8 h (day/night). Two types of LED lamps were used: LED I (Daplon-plus/2011 - emitted, red, blue and far red diodes at ratios 68,5%, 28,4% and 3,1%, respectively) and LED II (LED GrowBox – emitted red and blue light at ratios 8:1). Quantum irradiance was maintained at the same level in all treatments: 50 µmol m -2 s-1 during the first 3 weeks and later on 100-120 µmol m -2 s-1. All plants were fertigated twice a week using the same nutrient solution, contained macro and microelements. Plants were evaluated after 7 weeks of acclimatization. Both LED lamps used in this experiment resulted in greater weight, higher leaf area and better root development comparing to plantlets grown with HPS lamps

Carbohydrate content in the roots of strawberry tray plants as affected by the duration of cultivation and storage and its influence on fruit field

Changes in the levels of starch, sucrose and fructose in the roots of strawberry tray plants (cv. ‘Elsanta’) as affected by the duration of the gro wing period (8, 12, 18 or 20 weeks) were examined. Measurements of air temperature during the growing period were used to calculate cumulative chilling hours (<7 ̊ C). The largest accumulation of starch in the roots was found in the plants grown for 20 weeks , which was associated with the increased amount of chilling received by this group of plants (707 h). The lowest amount of starch was recorded in the roots of tray plants cultivated for 8 weeks (this group of plants had not been exposed to chilling temper atures at all). After storage ( - 1.5 to - 2 ̊ C in a cooling chamber) no starch and low concentrations of soluble carbohydrates (sucrose and fructose) were detected in the roots of the plants which had not been exposed to chilling (cultivated for 8 weeks). Als o, post - storage vigour and productivity were the lowest in this group of plants. There were no differences in fruit yield between the plants cultivated for 12, 18 or 20 weeks

Nuclear DNA content and ploidy level of apple cultivars including Polish ones in relation to some morphological traits

Apple species and cultivars differ in nuclear (2C) DNA content and ploidy level. The majority of these genotypes are diploids, but there are some triploids and a few tetraploids. Nuclear DNA content is a specific feature and its flow cytometric evaluation can be helpful in differentiating taxa. For many apple genotypes – including all the Polish ones, these characteristics are not known. 2C DNA was evaluated in relation to leaf, flower, fruit, pollen grain and stomata sizes as well as to the flowering time for seventy genotypes (including 46 Polish cultivars) gathered in the gene bank of the Research Institute of Horticulture, Skierniewice, Poland. For standard cultivars with the known chromosome number, 2C value was 1.71 pg for diploid cultivar ‘Alwa’ (2n=2x=34), 2.55 pg for triploid ‘Boskoop’ (3x=51), and 3.37 pg for tetraploid genome (4x=68) of mixoploid ‘McIntosh 2x+4x’. In 61 cultivars (including 41 Polish ones), the nuclear DNA content ranged from 1.58 to 1.78 pg indicating their diploid chromosome number. Five cultivars were identified as triploids (‘Bursztówka Polska’, ‘Pagacz’, ‘Rapa Zielona’, ‘Rarytas Śląski’ and ‘Witos’) owing to their nuclear DNA amount ranging between 2.42 and 2.58 pg. Leaf, flower, fruit, stomata and pollen grain sizes were on average significantly larger in triploids. Thus, in 3x plants the mean leaf surface was 49.1 cm², flower diameter – 52.4 mm, fruit weight – 204.7 g, stomata length – 32.1 μm and pollen grain diameter – 33.7 μm, whereas in diploids – 36.0 cm², 46.1 mm, 162.7 g, 28.4 μm and 30.7 μm, respectively. Pollen grain viability was on average significantly higher in diploids (75.6%), compared to triploids (22%). These results confirm that in apple, as in many other plant species, the higher ploidy level of triploids is generally associated with increased sizes of pollen grains, stomata, flowers, fruits and leaves but decreased pollen viability. No clear correlation between ploidy level and flowering time was found. In the case of mixoploid apple genotypes possessing diploid and tetraploid genomes, some phenotype observation is helpful in describing the ploidy level of the histogenic layers, L1 and L2. Small stomata sizes (similar to diploid) indicate diploid L1 and larger leaf sizes, compared to diploid counterparts, show tetraploid L2. The results will be used for breeding, in which it is important to determine maternal and paternal genotypes as well as the direction of the crossing that is of great importance in obtaining seeds and materials for further selection

Comparison of response of three strawberry cultivars grown under greenhouse conditions to water deficiency

W doświadczeniu określono wpływ deficytu wody w podłożu na wybrane parametry fizjologiczne, wzrost i plonowanie roślin trzech odmian truskawki (‘Elsanta’, ‘Elkat’, ‘Grandarosa’) uprawianych w szklarni. Wykazano zróżnicowanie reakcji poszczególnych odmian truskawki na suszę. Deficyt wody w podłożu (potencjał wody był utrzymywany na poziomie -30 kPa) ograniczył aktywność fotosyntetyczną oraz potencjał wody w liściach roślin. Największą stabilność aparatu fotosyntetycznego (wyrażoną parametrami wymiany gazowej i fluorescencji chlorofilu) w warunkach suszy stwierdzono w przypadku odmiany ‘Elsanta’. Rośliny tej odmiany charakteryzowały się także najwyższym plonowaniem, co wskazywałoby na jej większą odporność na niedobór wody w podłożu. Deficyt wody spowodował największe ograniczenie intensywności fotosyntezy, wzrostu oraz wielkości plonowania u roślin odmiany ‘Elkat’.The response of three strawberry cultivars (‘Elsanta’, ‘Elkat’, ‘Grandarosa’) to drought was examined by evaluating the yield and selected morphological and physiological parameters. Plants were subjected to two different water regimes: optimal irrigation (control), and reduced irrigation (water potential in the growing medium was maintained at a level -30 kPa, stress treatment). Genotypes differed in their response to water deficiency. Under water shortage conditions, the rate of CO2 assimilation and efficiency of photosynthetic apparatus (expressed by chlorophyll fluorescence parameters) were the highest in ‘Elsanta’. On the other hand, the severe inhibition of photosynthesis was observed in ‘Elkat’, which corresponded to the reduced biomass production. Taking all data into consideration it was concluded that cultivar ‘Elsanta’ appeared to be more drought resistant which was reflected by enhanced physiological and yield parameters