Effects of fruiting on the growth of Arabica coffee trees as related to carbohydrate and nitrogen status and to nitrate reductase activity

Abstract

Active vegetative and reproductive growth in field-grown trees of Coffea arabica L. in Viçosa (20º45’S, 650 m altitude), south-eastern Brazil, occur concurrently. The overall patterns of branch growth and leaf area gain were to a certain extent altered by fruit removal, with growth rates being remarkably greater in de-fruited trees. The content of N-NO3 was not affected by fruiting, whilst that of amino-N was greater in de-fruited than fruiting trees most of the time, but the differences were not large enough to have significantly contributed to the increased growth rates in de-fruited trees. Leaf nitrate reductase activity was greater in plants bearing fruit than in non-bearing ones most of the time; activity was roughly inversely associated with growth. Although the roots contained much more nitrate than the leaves, the root nitrate reductase activity was much lower and not affected by fruiting. Much of the restrictive effects of fruiting on vegetative growth appeared to be associated to starch exhaustion, in addition to the outstanding effect of supra-optimum temperatures per se.

Aspects of nitrogen metabolism in coffee plants

“…In accordance, coffee trees (or branches) bearing fruits exhibited higher leaf NRA than the deblossomed ones (Taleisnik et al 1989;Carelli et al, 1989;Amaral et al, 2001). Leaf nitrate concentrations followed the same trend of NRA suggesting that there is a preferential course of nutrient flow to the higher consuming branches (sink strength) (Cannell and Kimeu, 1971;Taleisnik et al, 1980;Carelli et al, 1989).…”

“…Nevertheless, there is a lot of controversy about this subject in the literature. Some reports have shown higher NRA in leaves (Carelli et al, 1990a;Da Matta et al, 1999;Amaral et al, 2001), and others in roots (Carelli and Fahl, 1991, Queiroz et al, 1991, 1993a.…”

“…These findings could explain, at least in part, the contrasting data in the literature concerning the partitioning of NRA in coffee plants. In this sense, higher NRA was obtained in roots than leaves when experiments were conducted under low irradiance (Carelli et al, 1991;Queiroz et al, 1991Queiroz et al, ,1993aCarelli and Fahl, 2005), and vice-versa under higher irradiances (Carelli et al, 1990a;Da Matta et al 1999, Amaral et al 2001Carelli and Fahl, 2005).…”

Ecophysiology of coffee growth and production

“…These fluctuations are unlikely to have been associated with soil moisture since irrigation does not alter the overall pattern of growth, although it may affect the rates of shoot growth . Such a periodicity is also apparently independent of reproductive growth, although fruitless trees may outgrow those bearing fruit Amaral et al, 2001;Castro, 2002). In fact, lowering temperatures in Viçosa would to a large extent trigger the declining growth rates through the quiescent phase; by contrast, temporary depression in shoot growth during the active growing season seems to be chiefly associated with high temperatures, as noted by Barros et al (1997).…”

Metabolismo de nitrogênio em dois sistemas de cultivo de café sob veranico da estação úmida

“…De acordo com CHeng & Schupp (2004), o transporte, metabolismo e acúmulo de açúcares nos frutos, de maneira geral, estão condicionados por fatores ambientais e práticas culturais. Os cafezais arborizados caracterizam-se por um período mais longo de permanência de fruto nas plantas (Muschler, 2001), resultando em maior capacidade de acúmulo de metabólitos, principalmente açúcares solúveis (Franck et al, 2006) e compostos nitrogenados (Amaral et al, 2001). Dessa forma, em janeiro, devido ao estágio de -foliar de cafeeiro (Coffea arabica L.) cv.…”