Each perennial woody plant is a highly integrated system of competing carbohydrate sinks (utilization sites). Internal competition for carbohydrates is shown by changes in rates of carbohydrate movement from sources to sinks and reversals in direction of carbohydrate transport as the relative sink strengths of various organs change. Most carbohydrates are produced in foliage leaves but some are synthesized in cotyledons, hypocotyls, buds, twigs, stems, flowers, fruits, and strobili. Although the bulk of the carbohydrate pool moves to sinks through the phloem, some carbohydrates are obtained by sinks from the xylem sap. Sugars are actively accumulated in the phloem and move passively to sinks along a concentration gradient. The dry weight of a mature woody plant represents only a small proportion of the photosynthate it produced. This discrepancy results not only from consumption of plant tissues by herbivores and shedding of plant parts, but also from depletion of carbohydrates by respiration, leaching, exudation, secretion, translocation to other plants through root grafts and mycorrhizae and losses to parasites. Large spatial and temporal variations occur in the use of reserve- and currently produced carbohydrates in metabolism and growth of shoots, stems, roots, and reproductive structures. A portion of the carbohydrate pool is diverted for production of chemicals involved in defense against fungi, herbivores, and competing plants. Woody plants accumulate carbohydrates during periods of excess production and deplete carbohydrates when the rate of utilization exceeds the rate of production. Stored carbohydrates play an important role in metabolism, growth, defense, cold hardiness, and postponement or prevention of plant mortality.

Carbohydrate sources and sinks in woody plants

The experiment to determine the effects of KNO3 and urea in manipulating the harvesting time and increasing yield as well as quality of nine years old mango ( Mangifera indica L.) cv. Amrapali plants was carried out at the BAU Germplasm Centre, Department of Horticulture, Bangladesh Agricultural University, Mymensingh during the period from September 2006 to July 2007. The five treatments included in the experiment were potassium nitrate at 4%, 6% and 8%; urea at 2% and 4% and the control (water spray). Foliar spraying of urea at 4% exhibited better performance in relation to terminal shoot length, number of leaves and leaf area and potassium nitrate at 4% gave superior results with respect to length and breadth of panicle and number of secondary branches per panicle compared to control. The plants sprayed with KNO 3 at 4% expressed earlier panicle appearance by 17 days as compared to delayed appearance of panicle in untreated control plants. The plants received KNO 3 at 4% produced the highest number of panicles per plant (220.67) whereas the control plants had the least number of panicles (107.67). Regardless of concentration, KNO 3 and urea manifested slightly earlier harvest (5 days) compared to control. Plants treated with KNO 3 at 4% noted the highest number of fruits per plant (136.67) compared to control (62.67). The treatment urea at 4% resulted in the biggest fruit (202.83g) and the control plants exhibited the smallest fruit (175.00g). Potassium nitrate at 4% gave maximum yield (23.14 kg/plant) as compared to minimum yield (9.12 kg/plant) in the control (water spray). Bangladesh J. Agril. Res. 38(1): 145-154, March 2013 DOI: http://dx.doi.org/10.3329/bjar.v38i1.15201

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Yield And Quality Of Mango (Mangifera indica L.) As Influenced By Foliar Application Of Potassium Nitrate And Urea

The shoot maturation phase is important for growing mangoes because it precedes the floral induction, when plants are under stress caused by high temperatures and low water availability. Abiotic stress could be alleviated by using plant biostimulant which alters the phytohormone and carbohydrates biosynthesis. Thus, an experiment was conducted to evaluate the use a plant biostimulant containing Ascophyllum nodosum to induce shoot maturation of mango cv. Palmer grown in semi-arid environment. The experimental design consisted of randomized blocks with four treatments, ten replications and five plants per parcel. Treatments consisted of: T1) biostimulant foliar spray + K fertilizer; T2) foliar spray with biostimulant alternating with K fertilizer; T3) individual foliar sprays with magnesium sulfate, potassium sulfate, sulfur and calcium fertilizers, potassium fertilizer and Ethrel®; and T4) Control treatment. The total soluble carbohydrates in leaves, buds and shoots, N, K and S leaf concentrations and fruit production were recorded. The carbohydrate concentrations, nitrogen, sulphur and potassium leaf concentrations and fruit production of mango depend on shoot maturation strategy. Shoot maturation strategy using biostimulant containing Ascophyllum nodosum alternating with K fertilizer from 30 days after PBZ could  be recommended for the production of mango cv. Palmer.

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A new approach to induce mango shoot maturation in Brazilian semi-arid environment

Abstract Poor uptake of nutrients not only deteriorates the quality but also the yield of horticultural crops. Among various macro and micronutrients, the role of K, Ca and B is very important. Therefore, balanced application and uptake of K and Ca and B can improve the quality and yield of mango trees. So, a field study was conducted with the hypothesis that combined application of K and Ca along with B would be effective to improve yield and quality of Mango cv. Summer Bahisht (SB) Chaunsa. There were two sources of Ca(CaCl2 and Ca(NO3)2) and three sources of K(KNO3, K2SO4 and K-Citrate) combined with boric acid (BA). All Ca and K sources were applied at the rate of 1% while BA was applied at 0.2%. As compared to control, a significant improvement in fruit set panicle-1 (35.7% and 50.0%), fruit retention (125% and 40%), shelf life (73.3% and 36.6%), total soluble solids (35.1% and 40.6%) and fruit yield (52.5% and 49.2%) in 2016 and 2017 respectively, confirmed the effectiveness of KNO3 (1.0%) + BA (0.2%). Between CaCl2 and Ca(NO3)2, application of Ca (NO3)2 was found more efficacious regarding improvement of quality and yield of SB Chaunsa. It is concluded that to improve the quality and yield of Mango cv. SB Chaunsa, KNO3 (1.0%) + BA (0.2%) is the best nutrients combination, and Ca(NO3)2 is a better option as compared to CaCl2.

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Effect of Foliar Application of Boron with Calcium and Potassium on Quality and Yield of Mango cv. Summer Bahisht (SB) Chaunsa

Combinations of fertilizer rates, foliar N sprays, irrigation practices, and paclobutrazol were studied to determine how much they could alter and/or improve mango (Mangifera indica L.) growth, flowering, and yield. Two treatment combinations derived from several years of prior studies of individual practices were compared: one combination was comprised of the best (BT) individual practices from the prior studies and included three applications of fertilizer, a 4% KNO3 spray application before flowering, paclobutrazol at 7.5 g/L, and weekly irrigation, and the other combination was comprised of the next best (NB) individual practices including two applications of the same amount of fertilizer, a 4% urea spray before flowering, paclobutrazol at 10.0 g/L, and biweekly irrigation. Both combinations significantly reduced terminal shoot growth and leaves per terminal shoot, advanced the date of flowering and harvest, increased panicle number, length and secondary branching, increased fruit set, fruit number at harvest, fruit size, and yield, with BT producing larger fruit and a greater yield than NB. Although both combinations produced fruit with higher quality than the control, the BT combination produced fruit with the higher total soluble solids, reducing, non-reducing, and total sugar content, and vitamin C content than the NB combination. Both BT and NB combinations of the optimums identified in the prior studies were successful at advancing bloom and harvest and increasing yield more than any of the optimum individual components alone, by 14-fold more than untreated trees for the BT combination, suggesting there were additive, if not synergistic, effects on mango. Further studies are warranted to assess the sustainability of these effects over longer periods of time, and to ascertain if the effects occur across mango cultivars and production environments.

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Combined Effects of Fertilizer, Irrigation, and Paclobutrazol on Yield and Fruit Quality of Mango

The effects of leaf applications of potassium nitrate (KNO3), alone and in combination with urea at different concentrations on flowering, fruit set and fruit quality of Tommy Atkins' mango grown in the rift valley of Ethiopia were evaluated. The trees were characterised by erratic flowering, continuous and high intensity of vegetative growth as well as irregular bearing. Uniform trees were selected for a randomised complete block design experiment with three replications and three trees per plot. Spraying was conducted initially on the immature postharvest flushes and then repeated after the flushes had matured and had dark green leaves. Potassium nitrate concentrations especially in combination with urea (5 litre solution of 4% KNO3+0.5 g urea tree−1 and 5 litres of 4% KNO3+I g urea tree−1) produced better results for most of the flowering and yield parameters. There was a non-significant difference for the qualitative parameters between the treated and non-treated trees. The supplementation of nitrogen...

Potassium nitrate and urea sprays affect flowering and yields of 'Tommy Atkins' (Mangifera indica) mango in Ethiopia

Gereelde ontledings van die koolhidraatfraksies in jong appelbome het getoon dat suiker 'n relatief klein gedeelte van die koolhidrate in die boomdele uitmaak, en veral in die wortels voorkom. Stysel akkumuleer in die wortels tot finale blaarval in die winter, waarna 'n afname in styselinhoud begin, en voortduur tot ongeveer sewe weke na bottyd. Hemisellulose kom in groot hoeveelhede in die houtweefsel voor waar dit hoofsaaklik struktureel van aard is. Dit wil voorkom asof hemisellulose gedurende die herfs in die wortelweefsel gemobiliseer word, moontlik om aktiefgroeiende haarwortels te onderhou. S.-Afr. Tydskr. Plant Grond 1984, 1: 92–95

Seisoensveranderinge in die koolhidraatinhoud van jong appelbome

Sterk eenjarige winterlote van 'n tien-jaar-oue Merton-793-moederplantasie is opgedeel in steggies van 30 cm lengte. Die basale steggie is gesny vanaf die punt van aanhegting, met die tweede en derde steggie in opeenvolgende posisies nader aan die lootpunt. Die posisie van steggies op die loot het geen verskil in bewortelings- persentasie voor bot tot gevolg gehad nie. Verskille in persentasie oorlewing tussen steggies vanaf verskillende lootposisies is egter verkry nadat steggies toegelaat was om te bot en te groei. Hierdie verskille het verband gehou met die werklike hoeveelhede koolhidrate wat die steggies bevat het. S.-Afr. Tydskr. Plant Grond 1985, 2: 127–129

P. J.C. Stassen

Papers

Potassium nitrate and urea sprays affect flowering and yields of 'Tommy Atkins' (Mangifera indica) mango in Ethiopia

Seisoensveranderinge in die koolhidraatinhoud van jong appelbome

Die rol van koolhidraatreserwes by kwekeryprestasie van appelhardehoutsteggies