AbstractSalt tolerance is largely dependent on a plant’s ability to maintain optimal water status in leaves. The adjustment of water relations under salinity involves changes in the transcriptional activity of genes encoding plasma membrane aquaporins (PIPs). Here, we report the effects of long-term or short-term treatments with moderate or strong salt stress on the expression of BvPIP1;1, BvPIP2;1 and BvPIP2;2 in the leaves of sugar beet, Beta vulgaris cv. Huzar, and its halophyte relative, Beta vulgaris ssp. maritima. Plants subjected to long-term treatment were watered with salt-supplemented media during a 32 day long culture period. Short-term salt treatments were executed either by immersing the petioles of excised leaves into salt solutions for 48h, or incubating excised leaf blades in salt-supplemented media for 20h. B. vulgaris ssp. maritima reacted to long-term salt treatment with a decrease in BvPIP1;1, BvPIP2;1 and BvPIP2;2 expression. Contrastingly, only BvPIP2;2 transcript was down-regulated by salinity in leaves of B. vulgaris cv. Huzar, whereas BvPIP1;1 and BvPIP2;1 did not vary in response to salt-treatments. On the other hand, the expression of BvPIP1;1, BvPIP2;1 and BvPIP2;2 was enhanced by salinity if salt solutions was supplied through leaf petioles, irrespective of genotype. PIP expression in excised leaf blades revealed a complex pattern of changes. BvPIP1;1 and BvPIP2;1 expression underwent a period of transient increase in both the control and salt-treated leaves. Furthermore, BvPIP1;1 expression was enhanced by strong salinity. BvPIP2;2 expression was up-regulated by strong salinity or up- or down-regulated by moderate salinity during the treatment period.
The Effect of Potassium Application on Sugar Beet (Beta vulgaris L.) under Salt Stress