Reduction In Total Uptake Research Articles

Macro- and micro-nutrient uptake pattern and their use efficiencies for maize (Zea mays) in maize-wheat (Triticum aestivum) cropping system under nutrient omissions

A 2-year (2012 and 2013) field experiment was conducted at ICAR-Indian Agricultural Research Institute, New Delhi to assess the effect of omitted nutrients on nutrient concentration and uptake and (nutrient use efficiency) NUE for maize (Zea mays L.) in maize–wheat (Triticum aestivum L.) cropping system. The STCR-based application of nutrients was more rewarding in terms of improved concentrations, uptakes and better NUE of macro (N, P, K) and micro-nutrients (Zn) in maize. This treatment increased the total uptake of N, P and K by 14.9, 12.5 and 9.3 %, respectively, over recommended rates of NPKZn application. The continuous omission of P resulted in 13.7, 11.5 and 4.7 % reduction in total uptake of N, P and K, respectively. Similar to P, omitting K to both crops continuously also resulted in reduction of total uptake of N, P, K, Zn by 22.1, 13.6, 23.4, 1.9, respectively. Omitting Zn to both maize and wheat crop during 2012 and 2013 did not influence total nutrient uptake significantly. Omitting P and K also exhibited reduced agronomic efficiency and apparent recovery. Balanced application of NPK to preceding wheat crop resulted in higher uptake of N, P and K by maize compared to absolute control and imbalanced application of N, NP or NKZn directly to maize crop during experimentation. Omitting N, P or K to maize resulted in reduction in NUE and uptake in maize during second study year.

Mechanisms for altered carnitine content in hypertrophied rat hearts.

Carnitine levels are reduced in hypertrophied hearts of rats subjected to aortic constriction (banding) and elevated in hypertrophied hearts of spontaneously hypertensive rats (SHR). In an attempt to determine the mechanisms for these alterations, L-[14C]carnitine transport was examined in isolated perfused hearts. Total carnitine uptake was significantly reduced by approximately 20% in hypertrophied hearts of banded rats at all perfusate carnitine concentrations employed. The reduction in total uptake was due to a 40% reduction in carrier-mediated carnitine uptake with no difference in uptake by diffusion. In contrast, carnitine uptake was not altered in isolated hypertrophied hearts of SHR. However, serum carnitine levels were elevated in SHR, which could result in increased myocardial carnitine uptake in vivo. The data suggest that altered carnitine content in hypertrophied hearts of aortic-banded rats is due to an alteration in the carrier-mediated carnitine transport system in the myocardium. However, altered carnitine content in hypertrophied hearts of SHR is not due to a change in the carnitine transport system per se but may rather be due to a change in serum carnitine levels.

Effect of Ethylene on the Uptake, Distribution, and Metabolism of Indoleacetic Acid-1-14C and -2-14C and Naphthaleneacetic Acid-1-14C

The effect of ethylene on the uptake, distribution, and metabolism of indoleacetic acid (IAA)-1-(14)C, IAA-2-(14)C, and naphthaleneacetic acid (NAA)-1-(14)C in cotton stem sections (Gossypium hirsutum L., var. Stoneville 213) was studied. Stem sections excised from plants pretreated with ethylene for 15 hours transported significantly less (14)C-IAA and (14)C-NAA than control sections. Concomitant features of the reduction of (14)C-IAA transport were an increase in decarboxylation and a trend toward a reduction in total uptake. With (14)C-NAA, however, total uptake was significantly increased, and decarboxylation was unaffected.(14)C-IAA was rapidly converted to indoleacetylaspartic acid and many other metabolites in both control and ethylene-pretreated stem sections. Following transport, similar amounts of (14)C-IAA were recovered in the apical absorbing portion of the control and ethylene-pretreated sections. Significantly more (14)C-IAA metabolites, however, were recovered in this region of the ethylene-pretreated sections.Conversely, (14)C-NAA was metabolized more slowly than (14)C-IAA under identical experimental conditions, with the only major metabolite being naphthaleneacetylaspartic acid. Following transport the apical absorbing portion of ethylene-pretreated stem sections contained significantly more (14)C-NAA than the controls. These results suggested that the disruption of auxin transport by ethylene cannot be explained in terms of a more rapid metabolism of auxin in the treated sections. The increased (14)C-IAA metabolites in the absorbing portion of ethylene-pretreated sections appear to be the result, rather than the cause, of the ethylene-mediated disruption of IAA transport.