Salt can have drastic effects on the growth and yield of horticultural crops; studies have estimated that salinity renders an about one-third of the world’s irrigated land unsuitable for crop production. Imbalances in soil salinity can cause ion toxicity, osmotic stress, mineral deficiencies, and drastic physiological and biochemical changes in plants. Salt stress can even cause plants to adjust their water usage — to conserve water, some plants close their stomata, thus restricting the entry of carbon dioxide (CO2) into the leaf and reducing photosynthesis. Scientists performed a comparative study of carbon fixation by different plant species under conditions of salinity. Tomato, lettuce, pepper, melon, and watermelon were tested in a greenhouse in southeast Spain. The net photosynthetic rate, gS, and transpiration rate of the plants were measured at atmospheric CO2 during the daytime and were related to the total chlorophyll, carbon, and mineral contents of each species.
Results have shown that the melon genome has 450 millions of base pairs and 27.427 genes. It is much bigger than the genome of its nearest “relative’, the cucumber that has 360 millions base pairs. “This difference is due mainly to the amplification of transposable elements. We didn’t find recent duplications within the genome, which are very common in plant species. We have identified 411 genes that can be related in disease resistance. They are few but, nevertheless, the melon has a high capacity of adaptation to different environments,” explains the CSIC scientist. During the work, when comparing this genome with others that are near philogenetically, they have observed how changes occur to the genome of this species, which is known for its high variability.