Bottom-cold stress was less harmful than cold-air stress on tomato seedling production treated with boric acid

Abstract

Boron is beneficial element can help plants face chilling stress. This research was arranged using factorial experiment based on randomized complete block design on Lycopersicon esculentum var. Infinity in Isfahan University of Technology due to having a new idea about bottom-cold and cold-air stress tomato seedling with boron application. There were two treatments having different boron (B1) concentrations (B1) 50.5 mM, and (B2) 75.82 mM. Three temperature treatment used as following: (1) the cold treatment used with vegetation chambers with low temperature (10 °C) (cold air), (2) the low nutrient solution (10 °C) temperature but the aerial part exposed to optimum temperature (bottom-cold) and (3) the last part, was the control plant (opt) keep in optimum root and shoot temperature (22 °C). Some physiological and biochemical characteristics were measured. The results were shown that boron uptake decreased in cold or stress as well as the water status of the plant which is suffering from cold-air stress greater than bottom-cold. Boron application, especially in higher concentration, improved some deleterious effect of cold stress, especially in the bottom-cold. The reason may refer to keeping photosynthesis traits in better level with B application. Cold-air stress, increased stress indices such as antioxidant and proline as well as glucose level and saturated/unsaturated fatty acid greater than bottom-cold stress. It was concluded that tomato was more resistant to bottom-cold stress than cold-air stress. Boron application increased the boron of leaves more effectively in the bottom-cold consequently increase plant tolerance to a chilling condition at the bottom-cold too.