Nitrogen storage and its interaction with carbohydrates of young apple trees in response to nitrogen supply

Abstract

Bench-grafted 'Fuji/M.26' apple (Malus domestica Borkh.) trees received a constant nitrogen (N) supply (10.7 mM) from bud break to the end of June, and were then fertigated with 0, 5, 10, 15 or 20 mM N in a modified Hoagland's solution for 2 months during the summer. In mid-October, half of the trees fertigated at each N concentration were sprayed twice with 3% urea, whereas the remaining trees served as controls. All trees were harvested after natural leaf fall and were stored at 2 degrees C. Five trees from each of the N treatment combinations were destructively sampled during dormancy to determine the composition of N and total nonstructural carbohydrates (TNC). As the N supply from fertigation increased, amounts of N in both free amino acids and proteins increased, whereas C/N ratios decreased. Foliar urea applications in the fall significantly increased amounts of N in both free amino acids and proteins, but decreased their C/N ratios. Arginine, the most abundant amino acid in both free amino acids and in proteins, accounted for an increasing proportion of N in free amino acids and proteins with increasing N supply from fertigation or foliar urea application. The ratio of protein N to free amino acid N decreased from about 27.1 to 3.2 as N supply from fertigation increased from 0 to 20 mM, and decreased further to 3.0 in response to foliar urea applications in the fall. Concentrations of glucose, fructose, sucrose and TNC decreased as the N supply from fertigation increased, whereas concentrations of sorbitol and starch remained relatively unchanged. Foliar urea applications decreased the concentration of each TNC component and the TNC concentration in each N fertigation treatment. A negative linear relationship was found between carbon in TNC and N in proteins and free amino acids. The sum of carbon in TNC, proteins and free amino acids remained constant in response to N supply from fertigation. However, foliar urea applications decreased the sum of carbon in proteins, free amino acids and TNC because about 21% of the decrease in TNC carbon was not recovered in free amino acids or proteins. Young apple trees store N and carbon dynamically in response to N supply. As N supply increases, an increasing proportion of N is found in the form of free amino acids, which have a low carbon cost, although proteins remain the main form of N storage. Furthermore, part of the carbon from TNC is incorporated into amino acids and proteins, decreasing the carbon stored as TNC and increasing the carbon stored as amino acids and proteins.

The effects of water, nutrient availability and their interaction on the growth, morphology and physiology of two poplar species

“…Similar results have been reported in an earlier study (Hamerlynck et al, 2004). Cheng et al (2004) have also found that as the N supply increases, the amounts of N in both free amino acids and proteins increase whereas the C/N ratio decreases. Water stress together with fertilization increased WUE (i.e., ␦ 13 C) in poplars, this result is consistent with previous studies (Brück et al, 2000;Welander and Ottosson, 2000;Li et al, 2003;Kondo et al, 2004) stating that WUE is significantly lower in well-watered treatments than in waterstressed treatments, but it increases with an increasing nutrient supply.…”

Effect of Postharvest Defoliation on Carbon and Nitrogen Resources of High-Yielding Sauvignon blanc Grapevines

“…N is the mineral nutrient for which vines have the greatest demand and the nutrient that most often limits growth (Keller 2010). Differences in vegetative growth and yield were mainly determined by reserve N and not CHO (Cheng et al 2004). Nitrogen and carbon are incorporated together in many physiologically important plant compounds such as amino acids, proteins, and enzymes (Kozlowski and Pallardy 1997).…”

Influence of Dormancy Level and Carbon Concentration on Freezing Hardiness in Bourse Shoot of 'Fuji' Apple Tree

“…앞서 언급한 바와 같이 사과나무의 내동성은 수체 내 탄수화물(carbohydrate)과 질소(nitrogen)의 함량에 영 향을 받지만 (Schupp et al, 2001), 탄수화물과 질소의 비 율인 C/N율에 의해서도 영향을 받는다 (Cheng, 2002;Cheng et al, 2004). 일반적으로 탄수화물은 단당류, 과 당류 및 다당류의 3가지 군으로 크게 나눌 수 있으며 (Byun et al, 2006), 식물 체내에 단당류 혹은 이당류가 많을수록 식물의 내동성은 증가하지만 다당류인 전분이 많으면 감소되는 것으로 알려져 있다 (Chae et al, 2006).…”