Sand Abrasion Injury and Plant Survival In Cotton Seedlings of Different Ages.

Several studies in Texas on cotton seedlings (Gossypium hirsutum L.) have shown that shoot growth efficiency is increased following sand abrasion injury compared with that of untreated controls.  Our overall hypothesis is that cotton seedlings with greater root-to-shoot biomass ratio (R/S), prior to soil abrasion injury, should be better able to withstand and recover from abrasion injury compared with cotton seedlings with lower R/S ratio. In a study conducted in a greenhouse we utilized the Texas wind tunnel to expose cotton seedlings of different ages to wind velocities of 15.2 m s^-1 with sand abrasive flux density of 0.42 g cm^-1 width per second for six treatment durations ranging from 0 (control) 5, 10, 20 30 to 40 minutes and mechanical pruning to remove all leaves with no wind. Cotton relative growth rate was expressed based on growing degree days rather than chronological time. Growth analysis (Relative Growth Rates, Net Assimilation Rates and Leaf Area Ratios) as well as biomass increments of the whole plant (including the roots) were calculated at two periods, 2 and 4 weeks after the wind-blown treatments.