Total non-structural carbohydrates in two well-drained native savanna grasses

Abstract

Variations of total non-structural carbohydrates (CNET) were studied in two native savanna grasses (Axonopus purpusii and Leptocoryphium lanatum) in 1989-1990 in Apure, Venezuela. In both species, the CNET concentration was determined in roots (0-20 cm) and lower stratum (0-7 cm) and upper (> 7 cm) above ground, at cut and at 1, 2-, 4-, 8-, and 12-weeks post-cut in rainy, transitional and dry seasons. In A. purpusii the highest values ​​were in roots and lower strata (4.8%), and in L. lanatum they were located in roots (9.0%). The highest values ​​(P <0.05) of CNET occurred during the dry season (4.6% in A. purpusii and 7.8% in L. Lanatum) and the lowest during the transition seasons (3.4% in A. purpusii) and rainy season. (2.4% in L. lanatum). After the cut-off, the CNET decreased (P <0.05) in all strata. In roots of A purpusii and L. lanatum, the CNET decreased (P <0.05) during two weeks postcut from 6.9 to 2.2% and from 5.4 to 1.4% in the rainy season; from 5.4 to 3.0% and from 15.5 to 4.0% in the transition and from 7.4 to 2.4% and from 21.1 to 6.6% in drought, respectively.