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R. M. Taylor

Abstract

A lanolin - potassium gibberellin (GA3) mixture when applied to the trunks of pecan seedlings, beginning 7-10 days after emergence and continuing at 10-14 day intervals for a total of 4 treatments, resulted in sufficient trunk growth for successful patch budding to be accomplished by the end of the third month of growth.

Free access

M.D. Taylor, S.J. Locascio, and M.R. Alligood

`Equinox' tomatoes (Lycopersicon esculentum Mill.) were grown during the springs of 2001 and 2002 with black polyethylene-mulch and drip irrigation on an Arredondo fine sand in Gainesville, Fla., to study the influence of water quantity, Ca source, and reduced K on incidence of blossom-end rot (BER), marketable fruit yield, and fruit and leaf Ca concentration. Tensiometers were used to schedule irrigation in main plots when the soil matric potential reached 10 or 25 kPa. Subplot nutritional treatments were no added Ca, Ca(NO3)2, Ca thiosulfate, CaCl2, CaSO4, and K rate reduced by 50%. Interactions between year and treatment were significant. During 2001, total marketable yields were higher with Ca(NO3)2 or CaCl2 compared to plants that received Ca thiosulfate and were higher from plants irrigated at 10 kPa than irrigated at 25 kPa. Number and weight of BER fruit were lower with Ca(NO3)2 and reduced K than with no added Ca and CaSO4. Leaf and fruit Ca concentrations were generally higher with Ca(NO3)2 compared to all other nutritional treatments. Leaf and fruit Ca concentrations were generally higher from plants irrigated at 10 kPa than at 25 kPa. The reduction of NH4 +-N, by the supply of N as NO3 -, and the addition of supplemental Ca reduced the incidence of BER, and increased the leaf and fruit Ca concentrations. During 2002, marketable yields were higher with CaSO4 than with CaCl2 and reduced K. Weight and number of BER fruit were lower with irrigation at 10 kPa than at 25 kPa. Leaf and fruit Ca concentrations were higher or similar from plants that received Ca(NO3)2 than with all other nutritional treatments. During the 2002 season, rainfall was less and temperatures and daily evapotranspiration (ET) were higher than in the 2001 season. In the 2002 season, 3.28 × 106 L·ha-1 of irrigation was applied as compared to 1.58 × 106 L·ha-1 in 2001. With an average Ca concentration of 76 mg·L-1 in the irrigation water, much more Ca was applied during the higher ET 2002 season. With the higher transpiration and temperature, water uptake and hence, Ca uptake were increased. During both seasons, the lowest Ca concentration was observed at the blossom end of the fruit and the highest Ca at the stem end of the fruit. Fruit Ca concentrations were lower and BER was 5 times higher in the lower ET, higher rainfall (lower irrigation) 2001 season compared to the higher ET, lower rainfall (higher irrigation) 2002 season. These data support that BER was a symptom of Ca deficiency and this deficiency was aggravated by high rainfall, low ET, and the resulting reduced irrigation applied and reduced Ca uptake.

Open access

R. M. Taylor and L. B. Fenn

Abstract

Water was translocated from pecan [Carya illinoinensis (Wangenh.) K. Koch ‘Burkett’], grape (Vitis vinifera L. ‘Thompson Seedless’) and tomato (Lycopersicon esculentum Mell. ‘Ace’) roots growing in a moist soil medium, across stem or crown tissue into roots growing in a dry soil medium, and was exuded during periods of high transpiration. Those portions of pecan and grape roots in a dry soil medium (wilting point) were maintained in an absorptive condition for 30 days, whereas tomato roots were injured.

Open access

R. Holubowicz, A.G. Taylor, M.C. Goffinet, and M.H. Dickson

Abstract

During imbibition, water always follows the same pattern when entering the seed testa in semihard seeds (SHS) of snap bean (Phaseolus vulgaris L.). Water first enters the raphe and the chalazal region of the testa (R-CT), then migrates circumferentially along the midline of the seed, leaving the lateral faces the last to be fully imbibed. The R-CT region is the main site of primary uptake of both water vapor and liquid water by SHS. The hilum, micropyle, and strophiole play only a minor role in water uptake in SHS. In comparison to the readily permeable seeds of ‘Bush Blue Lake 47’, SHS have more total phenols in the osteosclereid cells and more pectic substances in the palisade cells of the CT. The presence of these compounds may account for the impermeable nature of SHS. Measurements made of palisade cell length and width in the R-CT region revealed that cell length increased and width decreased in the chalazal testa region (CT) as seed moisture content increased from 6% to 12%. It is proposed that semihardening of bean seeds is mainly a result of the reversible physical changes in the length and width of the palisade cells in the R-CT region. Seeds imbibe at high moisture content (12%) because the palisade cells have stretched, which allows water uptake. Seeds are impermeable at low moisture content (6%) because the palisade cells change in size and form a physical barrier to water movement.

Open access

R. M. Taylor, L. B. Fenn, and C. A. Pety

Abstract

Several different split-root techniques, both horizontal zonation (1, 3, 6) and vertical zonation (2, 4, 7, 8), have been employed to study plant growth and water and nutrient uptake from differentially salinized root zones. High salinity level in one portion of the root zone may not affect overall plant performance if other portions of the root zone are relatively salt free (1, 3, 8). With uniform salinization, sodium chloride concentrations up to −0.8 MPa did not affect the 15N absorption rate in cotton, but osmotic pressures of −1.2 MPa substantially reduced it. However, water uptake and plant growth were affected to a greater extent than was 15N absorption (5).

Free access

N.R. Rice, M.W. Smith, R.D. Eikenbary, D.C. Arnold, W.L. Tedders, B.W. Wood, G.G. Taylor, B.S. Landgraf, and G.E. Barlow

Annual legume ground covers were evaluated in pecan (Carya illinoinensis) orchards to supply nitrogen and increase beneficial arthropods. Treatments were established at two sites, each with 5 ha of a `Dixie' crimson clover (Trifolium incarnatum) /hairy, vetch (Vicia villosa) mixture and 5 ha of grass sod. Data indicated that the legume mixture supplied over 100 kg·ha-1 N to the pecan trees. Beneficial arthropods were greater in orchards with legume ground covers than in orchards with a grass groundcover. Lady beetles and green lacewings were the most important spring predators, and green lacewings were the most important fall predator. The Species distribution on the ground covers differed from that in the canopy. Coleomegilla maculata lengi, Hippodamia convergens and Coccinella septempunctata were the most abundant lady beetle species in the legume ground covers, and Olla v-nigrum, Cycloneda munda, and Hippodamia convergens were the most abundant species in the pecan canopies. Beneficial arthropods appeared to suppress injurious pecan aphids.