Short Interval Leaf Movements of Cotton

Abstract

Gossypium hirsutumn L. cv. Lankart plants exhibited three different types of independent short interval leaf movements which were superimposed on the circadian movements. The different types were termed SIRV (short interval rhythmical vertical), SIHM (short interval horizontal movements), and SHAKE (short stroked SIRV). The 36-minute period SIRV movements occurred at higher moisture levels. The 176-minute period SIHM occurred at lower moisture levels and ceased as the stress increased. The SHAKE movements were initiated with further stresses. The SLEEP (circadian, diurnal) (1-3, 6, 9). The shorter cycle leaf movements are known to occur in several species of plants (4).In this study, evidence will be presented that the short interval leaf movements are separate and distinct from the circadian movements and that there are different types which occur at different moisture stresses. MATERIALS AND METHODSSeed of Gossypium hirsutum L. cv. Lankart were planted in 20-cm diameter plastic pots which contained a 50:50 mixture of peatmoss and perlite. The plants were grown in a greenhouse and were watered with the equivalent of 0.5 strength Hoagland's solution in tap water with periodic tap water flushing until they were at the 5 to 10 true-leaf stage. Routinely, the plants were transported into the laboratory in the afternoon and placed under the continuous illumination from a light bank containing six 40-w, 4-foot Gro-Lux F-40 lamps and two 200-w incandescent lights. The tops of the plants, depending on their height, were between 1 and 3 feet from the light bank and thus received between 3,000 and 15,000 ,uw/cm2 radiation which peaked at 660 nm. The temperatures were maintained between 29 40%. The plants were photographed with a 16-mm movie camera fitted with a time lapse drive and timers. After development, the sequences were projected directly on the chart paper of a recorder with the use of a special projector. The position of the tip of the leaf was marked as to its vertical components. In one case, the horizontal components were also graphed.Moisture Stress Series. For this series, the cotton seeds were planted in three pots each containing 650 g dry weight of peatmoss-perlite mixture. Another three pots were planted, each of which contained 3,000 g dry weight of Miller clay. Those in Miller clay were watered with distilled water only. At 12, 21, and 41 days after planting, respectively, one pot of the seedlings in the Miller clay containing two seedlings per pot was placed under continuous light at conditions previously described for about 2 weeks of photographic observation.The seedlings planted at different times in the peatmossperlite mixture were watered with 0.5 strength Hoagland's and were 20, 25, and 28 days from planting, respectively, at the time of initial photography. Each pot was placed on a scale so that weights could be observed and recorded. Only one of the pots was watered during the period of observation.At the end of the moisture stress sequences, the plants were pulled up, the potti...

Leaf Temperature and Transpiration of Field Grown Cotton and Soybean under Arid and Humid Conditions

“…In addition, leguminous crops including soybean would control leaf temperature by paraheliotropic leaf movement during midday (Hirata et al, 1983;Berg and Hsiao, 1986;Reed and Travis, 1987;!soda et al, 1993;!soda et al, 1994) . On the other hand, cotton leaves move diaheliotropically during the daytime, the movement increases leaf temperature (Lang, 1973;Miller, 1975).…”