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Anthurium (Anthurium andraeanum L.) is a cold-sensitive species originating from the tropical region of the world. This plant is widely cultivated all around the globe for the beauty of its ornamental spathes. Here, the effect of light quality on water loss of cut anthurium flowers was tested under chilling conditions. Cut flowers of two anthurium cultivars, ‘Calore’ (red spathe) and ‘Angel’ (withe spathe), were exposed to a cold temperature (4°C) under different light spectra, including darkness (D), red (R), blue (B), 7:3 ratio of red:blue (RB), and white (W). The results showed that ‘Angel’ flowers under the B light spectrum had the lowest relative water content (RWC) and specific surface area. It also showed the lowest spathe water content on a dry weight basis. The lowest vase life was obtained for ‘Angel’ under the B light spectrum, while the longest vase life was obtained under the R light, for both studied cultivars. Under the B light treatment, more open stomata were observed. Accordingly, the highest water loss was observed in all treatments with the B light, and the lowest percentage of water loss was observed in the D and R light, especially in ‘Angel’ flowers. In conclusion, the B light spectrum negatively influences vase life of cut anthurium flowers, through its effect on water relations of the spathes.

Quality of irrigation water is a critical factor for greenhouse production. A high concentration of soluble salts is the main reason for high electrical conductivity (EC) of irrigation water. The low water quality available for agriculture is the main problem in many places of the world. Plant growth-promoting bacteria are free-living soil bacteria that can help plant growth without having pathogenic effects. In the current study, three concentrations of NaCl (0, 40 and 80 mM, which resulted in EC of 1, 4 and 8 mS, respectively) were added to the irrigation water. Half of the salt-treated plants were fed with the rhizobacterium Bacillus subtilis (OD=0.6) to test whether it can reduce the problems of medium and high EC of irrigation water on lettuce plants, cultivated in Perlite medium. Growth parameters, including fresh and dry weights, leaf area, leaf number and plant height of control plants, were considerably improved by application of B. subtilis in the root medium of lettuce plants. Furthermore, the growth of plants exposed to medium and high EC was improved by the presence of B. subtilis in their rhizosphere. Polyphasic chlorophyll fluorescence transient parameters such as absorption flux, trapping flux and quantum yield for energy dissipation were decreased in plants with B. subtilis in their rhizosphere, while electron transport flux per reaction center was increased in B. subtilis-treated plants. In conclusion, B. subtilis can be used in the root medium of greenhouse plants to prevent the toxic effects of high EC of irrigation water.

In the current century, global warming is becoming an alarming issue causing an increase in the area of barren lands. Arid and semi-arid regions are characterised with shortage of water in both under- and above-ground environments. Plants with high water use efficiency should be considered for cultivation in those regions. Water loss is needed for cooling plant and absorbing minerals, however, excessive water loss can result in wilting. Plants control the water loss through adjusting the volume of stomatal guard cells and fine tuning the movements of stomata. Fine tune-functioning of stomata can help the plants to cope with drought conditions. Vapour pressure difference (VPD) between stomatal cavity and surrounding environment determines the water status of the leaf. In the short term, stomata respond in a regular way to VPD. However, when plants are exposed for a long term to conditions triggering stomatal opening (such as low VPD, prolonged lighting duration and air pollutants), the behaviour of the stomata in response to drought stress changes and the stomata are incapable of suitable response to closing stimuli (stomatal malfunctioning). Finding the reasons for occurrence of stomatal malfunctioning can help us to improve plant acclimation to dried environments. Exploring genetic variation in stomatal response among naturally occurring populations is the first step to figure out the mechanism controlling stomatal movements in different environments.