Effect of water deficit on gas exchange parmeters, growth and yield of two strawbery cultivars grown under greenhouse conditions

The response of two strawberry cultivars (‘Elsanta', ‘Sonata') 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. Cultivar ‘Sonata' presented high rates of net photosynthesis with high value of water use efficiency (a ratio of photosynthetic rate to transpiration rate) under water shortage conditions. Drought stress reduced leaf area in all cultivars, but root development was retarded only in ‘Elsanta'. Under water deficiency conditions reduction of yield was higher for ‘Elsanta'. ‘Sonata' appeared to be more drought resistant which was reflected by both growth and yield parameters.     ...

Controlled irrigation of poinsettia – a tool to plant shape regulation

The experiment was conducted to evaluate the effect of different irrgation managements during poinsettia cultivation. The existing systems of calculationg evaporative demand and thus irrigation frequency are usually based on growing media moisture sensors or climatic sensors (temperature, relative humidity and solar radiation). Poinsettia ‘Primero Red' was grown in pots (1,2 dm3) in greenhouse and irrigated using drippers, according to three different levels: I - irrigation at 40% ±2, (v/v) of water content in growing medium, II - automatically controlled irrigation according to continuous readings of plant weight (all plants placed on special balance connected with irrigation controller) III - irrigation at 72% ±2, (v/v) of water content. The water content in growng media in each treatments was controlled using capacitance probes ECH2O-10 (Decagon Devices, USA). The obtained results showed that irrigation control system based on continuous readings of specially designed balance connected to the computer gave very good results in poinsettia cultivation. Plant in this treatment had the best plant shape and the highest bract area. Moderate water deficit (irrigation at 40% of water content in growing medium) resulted in significant reduction in transpiration and stomatal conductance and thus reduced plant growth and quality. ...