Proline, which increases proportionately faster than other amino acids in plants under water stress, has been suggested as an evaluating parameter for irrigation scheduling and for selecting drought-resistant varieties. The necessity to analyze numerous samples from multiple replications of field grown materials prompted the development of a simple, rapid colorimetric determination of proline. The method detected proline in the 0.1 to 36.0 ~moles/g range of fresh weight leaf material.Cooperative investigations of D e p a r t m e n t of Grain Science a n d I n d u s t r y , C o n t r i b u t i o n no. 796, a n d E v a p o t r a n s p i r a t i o n L a b o r a t o r y , D e p a r t m e n t of Agronomy, C o n t r i b u t i o n no. 1306, K a n s a s Agricultural E x p e r i m e n t Station, M a n h a t t a n , K a n s a s 66506.

Stage of growth descriptions were developed for winter wheat (Triticum aestivum L.) which will apply to single plants or a community of plants. The growth stages are easily discernable and precise. Accumulations of dry matter, N, P, and K in leaves, culms, head, and grain were measured at each growth stage. Observations and plant samples were taken of fieldgrown winter wheat (cultivar ‘Centurk’) over the 3‐year period of 1975‐77. Plants were grown at the Univ. of Nebraska Agronomy Farm, Lincoln, on a Sharpsburg silty clay loam (Typic argiudoll). Plants for growth stage description and chemical analysis were randomly sampled from a field population and separated into leaves, culms, head, and grain as these plant parts developed. Growth stages are defined and illustrated. The 10 developmental stages are: O—Emergence, 1—Crown development and tillering, 2—Leaf sheath elongation, 3—Culm elongation (jointing), 4—Flag leaf emergence, 5—Peduncle elongation (heading), 6—Flowering (anthesis), 7—grain filling, 8—Stiff dough, 9—Hard dough (ripening), and 10—Maturity. Dry matter accumulation increased rapidly from stage 3 through stage 8. Translocation of dry matter from leaves to grain began at stage 6 and from culms and head to grain at stage 7. Nitrogen uptake was most rapid from stage 2 to stage 4 with 80% of the total accumulation occurring by stage 7. Over 70% of the total N uptake was translocated to the grain at maturity. Uptake of P and K was most rapid from stage 3 to stage 7. Seventy‐five percent of P uptake was translocated to the grain at maturity but only 15% of K present in the plant was found in the grain at maturity. The stage descriptions provide a standard for researchers, extension workers, producers, students, and agribusiness personnel to accurately define and determine the growth stages of winter wheat. The dry matter accumulation and nutrient uptake data provides part of the information necessary in making correct management decisions.

Free proline accumulation was measured in leaves of intact sorghum (Sorghum bicolor L. cv. Pioneer 846) and soybean (Glycine max. L. cv. Calland) grown in growth chambers and subjected to 'normal' drought stress. Stomatal diffusive resistance and leaf water potential were used to determine the degree of stress at the time of proline analysis.F.ree proline did not accumulate markedly in either species until each was severely stressed, indicating that proline is not a sensitive indicator of drought stress. Free proline accumulated under less stress in soybean than in sorghum. Since soybean is less drought resistant than sorghum, proline accumulation may be an indicator of drought resistance or susceptibility.

Net photosynthesis, respiration, and transpi-for the awnless and awn-clipped heads than ration were determined on heads and flag for the awned head. Respiration rates of the leaves of two isogenic lines of wheat (Tri-heads were L.7 and 3.0 times greater than ticum aestivum Ll em Thell) by measdring the respiration rates of the flag leaves of the the difference in CO, and water-vapor

A modern rainout shelter designed to open and close with an improved electronic control sytsem and to withstand high winds is described. It was installed in conjunction with drainage lysimeters to quantitatively evaluate evapotranspiration, physiological indicators of drought stress, and irrigation scheduling.