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Abstract
The relationship between canopy position and foliage concentrations of several phloem-mobile and -immobile essential nutrients was determined over a 20-fold range of average incident photosynthetic photon flux (PPF) (50 to 1000 μmol·s−1·m−2) in 7-year-old prune (Prunus domestica L., syn. ‘Prune d’Agen’) tree canopies. Mineral weight per unit of leaf area (LA) increased with increasing PPF within the canopy according to the relationship N > Ca > Mg > K > P. Dry weight per leaf area (DW/LA) increased 3-fold over the range of light exposures sampled. Leaf nutrient concentration expressed as percent dry matter (DM) did not vary with PPF. Both DW/LA and leaf N/LA appear to integrate the light microenvironment at the canopy coordinates of leaves sampled and may be correlated with photosynthetic capacity. Thus, these parameters may have diagnostic value in orchard management and crop production.
growth media nutrient analysis. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.
, Warren Stiles, and Mary Jo Kelly for their review and Mike Rutzke for assistance with nutrient analysis. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby
All leaves from 10 replicate Cocos nucifera L. `Malayan Dwarf' (COC) and Phoenix canariensis Chabaud (CID) trees were sampled for leaf nutrient analysis. In addition, the leaflets of the youngest fully expanded leaves and the third oldest leaves were divided into five groups along the primary leaf axis and these leaflets were then cut into thirds to determine nutrient distribution patterns within leaves and leaflets. Nutrient remobilization rates were calculated for N, P, K, Mg, and Mn. Results showed that N, P, and K were highly mobile within and between leaves of both species of palms. Up to 31% of the N, 66% of the K, and 37% of the total P in the oldest leaves were ultimately remobilized to newer leaves within the palm. Magnesium remobilization rates averaged ≈71% for CID but only ≈10% for COC. The middle-aged leaves appeared to be the primary sink for Mg in COC, rather than the youngest leaves as in CID. Manganese was also quite mobile in both species, with up to 44% of the total Mn remobilized in CID. Samples consisting of recently matured leaves were determined to be the most appropriate for Ca, Fe, Mg (COC only), and Zn, but oldest leaves are more suitable for N, P, K, and Mn analysis.
Growth and mineral nutrient content of creeping bentgrass [Agrostis stolonifera (L.) var. palustris (Huds.) Farw.] in response to salinity and humic acid (HA) application were investigated, and the effects of HA application on salinity tolerance was evaluated. Bentgrass plugs were grown hydroponically in one-quarter-strength Hoagland's nutrient solution containing HA at 0 or 400 mg·L-1 with salinity levels of 0, 8.0, or 16.0 dS·m-1. Clipping dry weight (DW), tissue water content, and net photosynthesis (PN) were measured weekly for 1 month. Maximum root length, and root DW from 0 to 10 cm and >10 cm root zones were determined 31 days after treatment (DAT). The turfgrass plugs were mowed three times weekly, with clippings collected and dried for mineral nutrient analysis. Salinity was inversely related to clipping DW, tissue water content, PN, and maximum root length. Salinity had less effect on root growth than top growth. HA treatment did not affect tissue water content, PN, or root growth of salt-stressed turf. Salinity decreased uptake of N, P, K, Ca, and S; increased uptake of Mg, Mn, Mo, B, Cl, and Na; and had no influence on uptake of Fe, Cu, and Zn. Application of HA at 400 mg·L-1 during salinity stress neither increased uptake of the mineral nutrients inhibited by salinity, nor decreased uptake of nutrients which were excessive and toxic in the salinity solution. In general, application of HA did not improve salinity tolerance of creeping bentgrass.
the optimum concentration, whereas the N and Fe concentration were lower than the critical soil test values ( Obreza and Morgan, 2008 ) ( Supplemental Table 1 ). Leaf nutrient analysis of 10 elements (N, P, K, Ca, Mg, Fe, Mn, Cu, Zn, and B) showed that
nutrient analysis. Soil and leaf tissues were sampled on day 60 to determine mineral nutrient concentrations in response to the treatment. Leaves were washed with a 1% acidic soap solution, oven-dried at 65 °C for 72 h, and finely ground using an analytical
leaves were removed from each plant at the end of the growth chamber study and sent to a commercial laboratory for complete nutrient analysis (nitrogen, phosphorus, potassium, magnesium, calcium, sulfur, boron, zinc, manganese, iron, and copper; Waters
the study, only ethylene data are available at 12 dS·m −1 . Nutrient analysis. About 100 mg of oven-dried leaf and root tissue was homogenized in 1 mL concentrated nitric acid. The extract was analyzed for Na + , K + , and Ca 2+ using an inductively
length, volume, surface area, and diameter. Shoot and root nutrient analysis. Roots were washed free of fritted clay and severed from shoots at 20 d after salinity initiation. They were washed with deionized water and dried at 80 °C for 3 d. The dry plant