Carbohydrate and protein metabolism of marandu grass affected by nitrogen fertilisation and number of cuts
¹State University of Southwest Bahia, Post-graduate programme in Animal Science, Spring Square, 40, Spring, 45700000, Itapetinga, Bahia, Brazil
²State University of Southwest Bahia, Department of Exact and Natural Science,
Spring Square, 40, Spring, 45700000, Itapetinga, Bahia, Brazil
³State University of Feira of Santana, Department of Biological Sciences, New Horizon, 44036900, Feira of Santana, Bahia, Brazil
⁴4State University Paulista Júlio of Mesquita Filho, Faculty of Agricultural and Veterinary Scienses of Jaboticabal, Vila Industrial, 14884900, Jaboticabal, São Paulo, Brazil
*Correspondence: angelseixas11@hotmail.com
Abstract:
Understanding the metabolism of tropical grasses in response to management practises imposed in pastoral environments allows for improvements in the management and use of mineral fertilisers. This study aimed to quantify metabolite content in different plant parts of Marandu grass (Urochloa brizantha), with a specific focus on the influence of nitrogen fertilisation and its effects following successive cuts. The treatments corresponded to four nitrogen (N) rates (0, 75, 150, and 225 kg N ha-1) and the number of cuts (one, two and three cuts). The plants were fractionated into leaves, stems, and roots to assess the content of water-soluble carbohydrates (WSC), starch, albumin, globulin, prolamin, and glutelin content. N fertilisation influenced the WSC and starch content in different parts of the plant, varying according to the cuts made. In the leaves and roots, fertilisation reduced the content of WSC and starch with one cut, as these were utilised as energy sources for assimilating the excess nitrogen in the soil. There was an increase in the concentration of all protein groups with nitrogen fertilisation in all parts of the plant with one cut. In plants cut two and three times, N fertilisation led to specific increases and decreases in different parts of the plants as an adaptive strategy for allocating resources as the number of cuts increased. Our results broaden our understanding of carbohydrate and protein metabolism in tropical grasses, thereby providing subsidies for the rational use of nitrogen fertilisers.
Key words:
cuttings, grasses, nitrogen, regrowth, reserves