Flutuação estacional de glicídios não-estruturais em alfafa

A field trial was carried out at the Agriculture Experimental Station of the Federal University of Rio Grande do Sul, located in Guaiba, RS, Southern Brazil, to evaluate the seasonal (spring, summer and winter) changes in the total non structural carbohydrates (TNC) reserves in plant roots and crowns of three alfalfa ( Medicago sativa L.) cultivars (Crioula, Hunter River and WL-518) and three progenies (1/7, 2/7 and 5/12) of the Crioula cultivar. Intensity or vigor of regrowth after cutting was evaluated also. In each season, a decrease in TNC reserves was observed: during spring and summer TNC content was reduced up to fourteen days after cutting, and 42 days in winter, recovering thereafter. The highest TNC level fluctuation occurred in spring, when forage yields were maximal. The highest TNC contents were obtained during spring and winter respectively, by cv. Crioula (29.6% and 25.8%), and progenies 1/7 (26.3% and 24.8%), 2/7 (27,1% and 23.1%) and 5/12 (25.7% and 28.0%). In each season, there was a significant (P<0,05) negative correlation between forage regrowth and TNC content. The productive and physiological performance of the 1/7, 2/7 and 5/12 progenies were similar to that of cv. Crioula, while the exotic cvs. Hunter River and WL-518 performed less satisfactorily.

[1]  J. Riboldi,et al.  Teste de progênies de policruzamento e cultivares de alfafa , 1984 .

[2]  C. Hoveland,et al.  Forage Yield and Quality of Phalaris as Affected by N Fertilization and Defoliation Regimes1 , 1978 .

[3]  Larry M. White,et al.  Carbohydrate reserves of grasses: a review. , 1973 .

[4]  K. Hodgkinson Physiological aspects of the regeneration of lucerne. , 1970 .

[5]  M. Massengale,et al.  Effect of Harvest Management and Temperature on Forage Yield, Root Carbohydrates, Plant Density and Leaf Area Relationships in Alfalfa (Medicago sativa L. cultivar 'Moapa')1 , 1968 .

[6]  Dale R. Smith,et al.  Effects of temperature and nitrogen supply on the growth of timothy (Phleutn pratense L.) , 1966 .

[7]  R. Blaser,et al.  Relationships Between Reserve Carbohydrate Accumulation and Growth Rate in Orchardgrass and Tall Fescue 1 , 1965 .

[8]  G. O. Mott,et al.  The Development of Carbohydrate Reserves in Alfalfa Seedlings Under Various Levels of Shading and Potassium Fertilization 1 , 1963 .

[9]  J. H. Reynolds,et al.  Trend of Carbohydrate Reserves in Alfalfa, Smooth Bromegrass, and Timothy Grown Under Various Cutting Schedules 1 , 1962 .

[10]  S. Dale Carbohydrate Root Reserves in Alfalfa, Red Clover, and Birdsfoot Trefoil under Several Management Schedules 1 , 1962 .

[11]  A. Dotzenko,et al.  Response of alfalfa in an alfalfa-bromegrass mixture to various cutting treatments. , 1950 .

[12]  V. G. Sprague,et al.  COMPOSITION OF THE ROOTS AND STUBBLE OF PERENNIAL RYEGRASS FOLLOWING PARTIAL DEFOLIATION. , 1943, Plant physiology.