Morphophysiological Changes of Cotton under Saline Stress in the Presence of Fusarium oxysporum sp
Feb 21, 2019
Fusarium wilt in cotton causes the greatest damage on sandy soil, acid, potassium deficient and saline soils. Because Fusarium wilt is more virulent under saline stress, the morphophysiological variations predisposing cotton plants under saline stress to the disease were evaluated. Seed of two cotton (Gossypium hirsutum L.) cultivars, Coker 304 (susceptible to wilt) and Acala SJ-2 (wilt resistant but susceptible in saline soils) were cultivated in hydroponic culture with non-saline nutrient solution (control group) or a range of nutrient solutions containing only FOV or only NaCl to EC 20mS/cm, or NaCl plus FOV. After 61 days, two transverse sections were cut from each plant of the four groups, one from the collar and one from the stem. From each sample, two characteristic were determined in the SEM, the average diameter of the xylem vessels (random selection, enlargement x156) and the total number of vessels per unit area. The experimental data (LSD test p<0.05) showed that the saline groups of plants had a lower diameter of the xylem vessels but a larger number of vessels per unit area. Both the greater number of vessels and the reduced lymph flow through these narrower vessels seem to be a precondition for cotton plants to be more susceptible to wilt.