|EPHRATH, JHONATHAN - Ben Gurion University Of Negev|
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/13/2009
Publication Date: 11/1/2009
Citation: Baker, J.T., McMichael, B.L., Burke, J.J., Ephrath, J., Gitz, D.C., Lascano, R.J. 2009. Sand abrasion injury and biomass partitioning in cotton seedlings. Agronomy Journal. 101(6):1297-1303.
Interpretive Summary: Millions of acres of crops are exposed to wind blown sand abrasion injury each year and in many instances the damage is thought to be sufficiently severe to require replanting. The goal of this study was to determine the effects of wind blown sand abrasion duration on cotton seedlings. Threes varieties of cotton seedlings were exposed to wind blown sand at abrasive flux densities. Seedlings of three cotton cultivars were exposed to no wind (untreated controls) or sand abrasive flux densities of 0, 0.1, 0.25, 0.35 and 0.5 g/cm width/s at a wind velocity of 13.4 m/s in a suction-type laboratory wind tunnel. Increasing exposure increased the amount of damage the plants received. Growth rates were measured during two time intervals following the sand abrasion treatments. The first time interval of two weeks following the sandabrasion treatment revealed a decrease in growth rate with increasing sand abrasion duration caused by the injured plants shedding damaged leaves. In the second time interval of two weeks after the first time interval we measured growth rates of the recovering plants. We conclude that damaged plants were receovered from sand abrasion damage by reallocating new biomass to the damaged shoots at the expense of roots.
Technical Abstract: Millions of acres of crops are exposed to wind blown sand abrasion injury each year and in many instances the damage is thought to be sufficiently severe to require replanting. The goal of this study was to determine the effects of wind blown sand abrasion duration on cotton seedlings. Seedlings of thress cotton (Gossypium hirsutum L.) cultivars were exposed to wind velcities of 13.4 m s-1 with sand abasive flux density of 0.42 g/cm width per second for six treatment durations ranging from 0 to 40 minutes. Plants were destructively sampled at the time of the sand abrasion treatment and also at approximately two and four weeks after exposure. These three sampling dates provided two time intervals for assessing the amount of plant damage and re-growth using classical growth analysis. With increasing sand abrasion treatment time, leaf area and lear stem, and total biomass were all significantly reduced while final number of mainstem nodes were increased (P< 0.05). Cultivar differences in leaf mass were significant only at the second destructive sampling date (P<0.05). For the first harvest interval, between the first and second destructive sampling, shoot relative growth rate (RGR) and net assimilation rate (NAR) decreased with increasing sand abrasion treatment time presumably due to the loss of damaged leaf biomass and reductions in light interception. Re-growth during the second harvest interval revealed the opposite pattern with RGR and NAR both increasing with increasing sand abrasion treatment time. During the second harvest interval, the increase in shoot RGR and NAR with increasing prior sand abrasion damage may be the result of remobilization of stored assimilate. Leaf area ration (LAR) was not affected by treatment time in either harvest interval. Thus, in both harvest intervals variation in RGR depended mainly on NAR rather than LAR.