sources used were limestone ammonium nitrate (LAN, N = 28%) (for N trial), single superphosphate (P = 10.5%) (for P trial), and potassium chloride (K = 50%) (for K trial) applied as post plant 1 week after planting in the form of granules. All plants
A xylem mutant (vse) was isolated from a Bambusa edulis (Odashima) Keng plantlet following vegetative micropropagation and subculture for 7 consecutive years and induced to proliferate in medium supplemented with 0.1 mg·L-1 (0.5 μm) thidiazuron (TDZ) and to develop roots in medium supplemented with 5 mg·L-1 (26.9 μm) α-naphthaleneacetic acid (NAA). Subsequent investigations comparing the growth habits of mutant plantlets with those of the wild type indicated that the growth of the former was retarded in a greenhouse. Several morphological abnormalities were observed in the vse mutant: it had thinner stems with fewer trichromes on the surface; the xylem vessels were smaller in diameter and contained crystal-like structures in the pith; the leaves were shorter and narrower with a sharp leaf blade angle; the roots were thinner and contained fewer xylem cells. The cation concentrations of both the mutant and wild type were similar in the in vitro analysis, except for those of iron and potassium, which were lower in mutant leaves in vivo. In 2-month-old mutant plants, iron chlorosis was observed on young leaves and a potassium deficiency was observed on older leaves. After 1 year of growth in the greenhouse, all of the wild-type plants had survived, but only 27% (16/60) of the mutant vse plants were alive.
monocots, palms have different nutritional requirements than dicot trees or shrubs. Most notable is the high potassium requirement of palms, an element that is rarely deficient in dicot trees. The purpose of this article is to review the most common
A 4-year field study on pecan [Carya illinoinensis (Wangenh.) K. Koch] provided indirect support of the supposition held by some U.S. pecan growers that air-blast foliar sprays of potassium nitrate (KNO3) plus surfactant enhances nut yield. While these treatments did not measurably influence yield components, foliar K nutrition, or net photosynthesis, they did suppress “yellow-type” aphid populations. While air-blast sprays of water alone suppressed aphid populations, the inclusion of KNO3 plus surfactant provided an additional level of suppression.
The influence of potassium (K) on respiratory behavior, flesh firmness, and internal color of watermelon (Citrullus lanatus) was studied. Two cultivars (Crimson Sweet and Sangria) were planted at the Univ. of Florida research station, Gainesville. The fruits from both cultivars were harvested at two different stages of maturity (25 days and 35 days after anthesis). Respiration and ethylene production were measured using gas chromatography under a static system. The internal color was measured by a colorimeter, while the flesh and rind firmness were measured by a instron Universal pressure tester. Carbon dioxide and ethylene production were non-climacteric in behavior and were not greatly affected by K treatment or cultivar.
Release rates for 13 commercially available soluble and controlled-release K fertilizers were determined in sand columns at 21C. Potassium chloride, KMgSO4, and K2CO3 were leached completely from the columns within 3 or 4 weeks. Osmocote 0N-0P-38.3K, Multicote 9N-0P-26.7K, the two S-coated K2SO4 products, and Nutricote 2N-0P-30.8K Ty 180 all had similar release curves, with fairly rapid release during the first 20 to 24 weeks, slower release for the next 10 to 12 weeks, and virtually no K release thereafter.
A field planting of ‘Bluecrop’, a mature highbush blueberry (Vaccinium corymbosum L.), on a Berryland soil type was subjected to differential levels of K fertilization over a 6-year period. Fruit yield and berry size were related to fertilizer treatment, leaf composition, and available soil K analysis. Blueberry production was highest at a 40 kg K/ha rate of potassium sulfate fertilizer which resulted in a leaf K sufficiency range between 0.45% and 0.55% K. Available soil K was significantly correlated to fruit yield.
Pot chrysanthemums (Chrysanthemum ☓ morifolium Ramat. ‘Bright Golden Anne’) were grown vegetatively for 5 weeks at 10 application rates of K. Two critical K levels were determined by correlating top fresh weights with K concentration in the most recently mature leaves. The critical foliar level associated with maximum yield was 2.3% K and that associated with 90% of maximum yield was 1.3% K. Potassium concentrations in leaves showing the earliest signs of K deficiency symptoms ranged from 0.6 to 0.7% K.
species examined by Frantz et al. (2008) , all 14 accumulated additional amounts of Si in their leaves when supplemented with potassium silicate. Leaf tissue concentration varied from 237 mg·kg −1 Si for petunia ( Petunia × hybrida Vilm. ‘White madness
Almond [Prunus dulcis (Mill.) D.A. Webb] yields have increased substantially since the 1961 publication of the Univ. of California (UC) guidelines for leaf potassium (K). Numerous growers and reputable analytical laboratories are concerned that the recommendations for leaf K are inadequate. A highly productive almond orchard with low leaf K was selected to reassess the leaf K critical value of 1.1% to1.4% and determine the relative sensitivity of various yield determinants to inadequate K availability. Baseline yields for 100 individual trees were measured in 1998 and four rates of potassium sulfate were applied under drip irrigation emitters to establish a range of July leaf K concentrations between 0.5% and 2.1%. No relationship was observed between leaf K and post-treatment yield measurements made in 1999. We also monitored individual limb units on trees from the treatment extremes for effects of low K availability on flower number, percentage fruit set, fruit size, spur mortality, and vegetative growth (potential fruiting sites in subsequent years). Those measurements indicated that although current-year yield determinants (percentage fruit set and fruit size) were not influenced by K deficiency, components of future yield were impacted negatively by low K availability: mortality of existing fruiting spurs was increased by K deficiency and growth of fruiting wood was reduced.