bluuebunny/crossref_metadata_2025 huggingface dataset:
HIGH-PRESSURE GAS ATMOSPHERES AND ANESTHETICS ALTER THE CHILLING SENSITIVITY OF PLANTS
Authors: Saltveit Mikal E.
Published: April 2024

Changes in membrane fluidity at low, non-freezing temperatures are thought to be involved in chilling injury - a physiological disorder of many economically important plants, e.g. banana, cucumber, maize, rice, and tomato. Atmospheres of 12 MPa He or N2 increased the rate of ion leakage from excised cucumber cotyledon discs, cucumber hypocotyl segments and tomato pericarp discs and also increased the threshold temperature at which chilling occurred by 2° to 6°C. Exposure to vapors of the mammalian anesthetics halothane and methoxyflurane reduced chilling injury in the same tissues. The relative effectiveness of the two anesthetics in reducing chilling injury was similar to their relative effectiveness in inducing anesthesia in animals and their relative lipid solubilities. The response of the tissues to halothane and methoxyflurane, which are known to increase membrane fluidity, and to high pressures, which are known to reduce membrane fluidity, are consistent with the hypothesis that a cold-induced phase transition of membranes could be responsible for chilling injury.
GROWTH AND DEVELOPMENT OF CATHARANTHUS ROSEUS UNDER VARIOUS ENVIRONMENTAL CONDITIONS
Authors: Pinchbeck Margaret , McAvoy Richard J.
Published: April 2024

In recent years, Catharanthus roseus has become a popular bedding plant, but at present there is little cultural information available for growers. This study examines the effects of four different temperature regimes and two light levels on three cultivars of Catharanthus. Average daily temperature regimes ranged from 15.3°C to 27.3°C; light intensities were 125 μmolm-2s-1 and 250 μmolm-2s-1. Plants were harvested as each successive pair of true leaves reached 1.5 cm in length, from the first true leaf stage until flowering. Measurements included internode length, leaf length, leaf area, dry weight of stem and leaves, and number and length of shoots. The plants grown at the lowest temperature regime took four times as long to flower as those grown at the highest temperature regime. Plants grown at the coolest temperature also exhibited chlorosis, stunting, and unusual flower formation. Information obtained from this study should assist growers in determining their planting schedule and the optimum greenhouse temperature for desired plant habit.
STEM ELONGATION IN `CARA MIA' ROSES
Authors: Bravo-Plasencia Francisco , Lieth J. Heinrich
Published: April 2024

Stem length of cut flower roses is one of the primary determinants of the sales price. Thus knowledge of the process of shoot elongation is useful in optimization of rose production. In this study shoot elongation was investigated by continuously logging `Cara Mia' rose shoot length using linear displacement position sensors (LDPS). Under natural conditions, elongation was found to occur mainly at night. The objective of this study was to investigate the role of environmental factors on rose stem elongation and to determine whether the process was related to an endogenous circadian rhythm or the absence of light. Measurements were made under various photoperiodic conditions (0, 8, 10, 12 and 24 hours night) and various temperature regimes. Under alternating light/dark regimes, regardless of photoperiod, shoot elongation rates follow a cyclical pattern with maximum values during dark periods and lower rates during periods of light. The elongation rate declined abruptly with the beginning of the light, suggesting that phytochrome activity might be responsible for this cessation of elongation. Under continuous light and constant temperature, the cyclical behavior was also observed, although the amplitude of the rhythm was smaller than under continuous light.
LETTUCE FOR PROCESSING IN LATIN AMERICA: A McGROWING PROBLEM FOR THE FAST FOOD INDUSTRIES
Authors: Decoteau Dennis R. , McMahon Margaret J.
Published: April 2024

Latin America is targeted as one of the most rapidly growing areas for expansion for McDonald's International. For example, McDonald's opened its first store in Mexico in 1985 and now has over 50 stores in that country. McDonald's is projecting to have over 100 stores in Mexico by the year 2000. Producing vegetable crops in the same country as a store is desirable to reduce shipping problems and to enhance vegetable production within the country. Problems with lettuce in Latin America include field production (poor growth and yields) and postharvest processing and handling (short shelf life). Beginning in 1992, field studies in cooperation with McDonald's International and Asgrow Seed Company were established in three field sites in Mexico and one site in Panama to determine seasonal uses of varieties (Mexico and Panama) and sites (Mexico) in order to provide quality year round production of lettuce for processing. Results suggest that varieties acceptable for trade in fresh market may not have desirable characteristics during processing (color and cut) and storage (shelf life and odor). In addition, the introduction of new varieties may be needed for year-round production.
IMPACT OF PLANTING METHOD AND SEED COLOR ON ROOT DEVELOPMENT OF JICAMA (Pachyrizus erosus (L) Urban).
Authors: Fernandez Maria V. , Warid Warid A. , Loaiza Juan M. , Martínez Jaime J.
Published: April 2024

Direct seeding and transplanting were implemented on April 3, 1991. Plants aged 20 to 45 weeks were monthly sampled. Fresh and dry weight of root, diameter, length, and root type were recorded. Fresh and dry weight of root were significantly affected only by plant age. The increase occurred at the age of 39 up to 45 weeks. This period coincided with a daylength of 10 hours. Roots of 45-week-old plants had the maximun fresh weight, 187.7 g and dry weight, 26.7 g. The interaction between planting method and plant age had significantly affected root diameter. It averaged 17.7 cm in directly seeded, 45-week old plants. The incidence of forking was significantly affected by the interaction among planting method, plant age, and root type. The least occurrence of forked roots was in directly-seeded plants aged 22 to 39 weeks. Three colors: green, brown, and brownish-green of commercial seeds were recognized. Root characters of mature plants grown from transplants were studied. Brownish-green seeds produced plants having greater and thicker roots. Average fresh and dry weight was 202 and 25 g, respectively. Root diameter averaged 12.9 cm.
STUDIES ON THE PRODUCTION OF OFF-SEASON JEWS' MALLOW IN EGYPT.
Authors: Abou-Hadid A. F. , Gaafer S. A. , El-Shinawv M. Z. , Medany M. A , El-Beltagy A. S.
Published: April 2024

Jews' Mallow (Melokhia) Corchorus olitorus, is a very important leafy vegetable for the Egyptians all year round, except for winter period. Short days and low temperatures accelerate the flower initiation and inhibits the vegetative growth entirely. Some supplimentary light of 8000 lux for one or two hours after sun-set, or as a flash for 10 min. at mid-night have been tried. The obtained results showed that two hours of artificial light after sun set inhibits the flowering and encourages leaf number, leaf area, plant height, plant fresh and dry weight, and leaf/height ratio. The obtained data were discussed in relation to the prevailed microclimatic conditions.
KANGKONG — A PROMISING SUMMER LEAFY VEGETABLE OF BANGLADESH
Authors: Sarkar Asit K. , Chadha M.L. , Hossain A.K.M. Amzad
Published: April 2024

There is shortage of vegetables in general in Bangladesh during rainy season. So, Kangkong (Ipomoea reptans) was introduced almost forty years back in Bangladesh as a fast growing nutritious green leafy vegetable suitable for growing during summer and rainy season. However, being a vine type vegetable, it quickly spreads over the land and leaves get soiled up, making them unsuitable for marketing. For search of an errect type variety the scientists of BARI were able to develop a line of kangkong which was released in 1983 in the name of Gimakalmi. This has become very popular in many parts of the country and thus contributing towards alleviation of vitamin A deficiency which is very much prevalent in the country. In the above context, two more kangkong lines, namely KG 002 (broad leaf) and KG 003 (pointed leaf) were introduced from AVRDC and their adaptibility and performance were evaluated during 1991. The leaf yield of KG 002 was found to be higher (46.0 t/ha) than Gimakalmi (35.8 t/ha) and KG 003 (32.0 t/ha). However all the lines were similar in growth habit and reaction to diseases and pests.
LOW-TEMPERATURE STORAGE OF ALYSSUM, VINCA, NEW GUINEA IMPATIENS, AND TUBEROUS BEGONIA PLUGS
Authors: Heins Royal D. , Wallace Thomas F.
Published: April 2024

Alyssum, vinca, New Guinea impatiens, and tuberous begonia seedlings in plug cells were stored in coolers to determine the effects of temperature, light, and storage time on growth and forcing time of seedlings after transplanting. Optimum storage temperatures for each crop were also determined. Photosynthetic photon flux densities of 0, 1, and 5 μmol m–2 s–1 were combined with temperatures of 0.0, 2.5, 5.0, 7.5, 10.0, and 12.5C to create 18 storage environments. Sample plants were removed from each treatment at 1-week intervals for 6 weeks, and were forced into flower. Temperatures of 5°C or less caused chilling injury on New Guinea impatiens and vinca. No chilling injury occurred on Alyssum at any temperature while chilling injury occurred on tuberous begonia after 3 weeks at 0C. Flowering of New Guinea impatiens and vinca was not delayed on plants not damaged by chilling injury. Increasing duration of dark storage resulted in flowering delay of alyssum and tuberous begonia. As dark-storage duration increased, alyssum plants elongated, etiolated, and then died. In general, all plants stored better in the light than in darkness. Optimal storage temperatures were 0-5C for alyssum, 7.5-12.5C for vinca and New Guinea impatiens, and 5 to 7.5C for tuberous begonia.
FACTORS ASSOCIATED WITH REDUCED POSTPRODUCTION QUALITY OF CHRYSANTHEMUM FOLIAGE PRODUCED UNDER HIGH NUTRITIONAL REGIMES
Authors: Carver Stephen A. , Tayama Harry K.
Published: April 2024

Dendranthema grandiflora Tzvelev., `Spirit' and `Torch' were produced under three water-soluble fertilizer (WSF) and one controlled-release fertilizer (CRF) regimes, with or without weekly CaCl2 sprays during the last three weeks of production to evaluate their influence on postproduction foliar longevity. Foliage of plants produced with 400 mg·liter–1 N (Peter's 20N-4.4P-16.6K) declined 1 to 2 weeks earlier than those produced with 400 mg·liter–1 N (Hydrosol + NH4 NO3), and 3.5 to 5 weeks before plants fertilized with 100 mg·liter–1 N (Hydro-sol + urea + NH4 N03) or 1 kg N·meter–3 growing medium (Osmocote 14N–6.2P–11.6K). Calcium chloride had no influence on foliar longevity. Plants receiving either 400 mg·liter–1 N treatment were generally larger (plant height and diameter), fuller (total and average leaf area), more vigorous (leaf dry weight per unit leaf area), and darker green in color (`Spirit' only, chlorophyll content per unit leaf area). Plant receiving WSF treatments had less than 0.5x the root system (dry weight) of CRF plants at harvest. Postproduction foliar longevity was most significantly and consistently correlated with foliar and growing medium nitrogen content. Relationship of postproduction foliar longevity with leaf soluble protein, carbohydrate, and starch content will be presented.
EFFECTS OF LOW O2 ON SENESCENCE OF CARNATION FLOWERS (DIANTHUS CARYOPHYLLUS L. cv. ELLIOTT'S WHITE)
Authors: Solomos Theophanes
Published: April 2024

Additions of adjuvants which inhibit the biosynthesis or action of C2H4 show that the climacteric rise in respiration during senescence of cut carnations is a facet of ethylene action and not senescence as such. The rate of CO2 output of carnation flowers was diminished in a dose-dependent mode by low O2. The data indicate that the diminution of respiration by low O2 may not be attributed to the restriction of either of the mitochondrial terminal oxidases. The steady-state concentration of ATP was similar in both air and 2% O2-treated flowers. 2% O2 eliminated for 32 days any rise in C2H4 evolution. In addition the longevity of the flowers kept under 2% O2 was longer than those which were treated with STS. The results are taken to indicate that hypoxia affects developmental events leading to the induction of C2H4 and/or the synthesis of transducer of C2H4 action.
DOSE RESPONSE CURVES AND CARRIER EFFECTS ON ROOTING
Authors: Maynard Brian K. , Johnson William A.
Published: April 2024

Auxins are indispensable for vegetatively propagating many woody plants. The rooting of stem cuttings treated with auxin varies with shoot maturation, phenological age and stock plant nutrition. Sensitivity to applied auxin is important both practically and for understanding the physiology of root formation. Applying optimal auxin concentrations is often the key to successful cutting propagation. Auxin dose-response curves for rooting usually show increased rooting with increasing auxin concentration to an optimum, followed by rooting inhibition and phytotoxicity at supra-optimal rates. These curves will be used to analyze dose response kinetics for common rooting hormones and carrier formulations. Dose-response curves were developed, using cuttings of Ilex glabra — inkberry holly, to evaluate IBA and NAA dissolved in 50% aqueous ethanol (EtOH) or 40% aqueous polyethylene glycol (PEG). Few differences were evident in the response curves of auxin dissolved in EtOH or PEG at concentrations of 0 to 75 mM. PEG yielded higher root numbers at the optimal concentrations of 10-20 mM NAA and 30-50 mM IBA. Both the stimulation and inhibition of rooting were more sensitive to NAA than IBA. Decreasing root length and increasing basal rooting inhibition were good indicators of auxin toxicity. These results further our knowledge of carrier effects on rooting and the potential of dose response analysis for studying adventitious root formation in cuttings.
EFFECTS OF IN VITRO-FORMED ROOTS ON WATER STATUS AND PHOTOSYNTHESIS OF TISSUE CULTURE APPLE SHOOTS.
Authors: Díaz Juan C. , Shackel Kenneth , Sutter Ellen
Published: April 2024

Apple shoots were cultured in a MS medium with agar. Whole-plant stomatal conductance and net photosynthesis were measured in a temperature-controlled room with a modified steady state porometer coupled to an IRGA. The gas exchange cuvette was maintained at a steady 95% RH. Once a steady state conductance was reached, a light stimulus (about 350 μmol m–2 s–1) was applied to measure photosynthesis. At the end of the gas exchange measurements, shoot relative water content was determined. Rooted shoots had higher values stomatal conductance, net photosynthesis and shoot relative water content compared to shoots without roots. Both conductance and photosynthesis were correlated to shoot RWC. These results suggest that in vitro roots improve plant function, measured as conductance and photosynthesis, by allowing the plant to have a higher water status compared to shoots that lack shoots.
RESPONSES OF YOUNG PEACH TREES TO ROOT CONFINEMENT
Authors: Rieger Mark , Marra Franco
Published: April 2024

Rooted cuttings of Nemaguard peach (Prunus persica (L.) Batsch.) were grown in 0.18, 0.36, 0.90, and 2.40 liter containers for 16 weeks to study the influence of root confinement on growth, gas exchange, water uptake, and leaf carbohydrate and nutrient content. Leaf area and stem length were reduced by root confinement beginning 6-7 weeks after transplanting, and differences among treatments increased through week 16. Final tree dry weights were reduced 51% over a 13-fold change in rooting volume, but dry weight partitioning was largely unaffected. Consistent reductions in CO2 assimilation and leaf conductance for confined trees did not occur until after week 11. Sorbitol and starch accumulated earlier in leaves of trees in smaller containers, but sorbitol was reduced and starch was unaffected by container volume at week 16. Despite similar soil fertility, leaf nutrient concentrations were reduced —two-fold by root confinement, except N (reduced 38%), yet characteristic deficiency symptoms were not observed. Initial mechanism(s) limiting growth were not gas exchange rates, levels of nonstructural carbohydrates, or drought stress, although nutrient deficiency cannot be ruled out as a factor limiting growth of trees with restricted rooting volume.
EFFICACY OF A COPPER HYDROXIDE/LATEX PAINT FORMULATION FOR ROOT - PRUNING 41 SPECIES OF CONTAINERIZED NURSERY STOCK
Authors: Krieg Randon J. , Witte W. T.
Published: April 2024

The root system of containerized nursery stock may become undesirably coiled or matted on the outer surface of the media. Various copper formulations painted on the interior of the container surface have been shown to control undesirable root growth in a few species. We tested a commercial formulation of 100 g/l copper hydroxide in a flowable latex paint formulation (SpinOut™) on 41 tree, shrub, and herbaceous species. Plants were grown 4 months in 7.5×7.5×15cm containers, either treated or untreated. Root density was evaluated on a scale of 1 to 5 (no roots on the surface to heavy rooting). Analysis showed treated containers prevented roots from growing on the media surface in all species tested except Magnolia liliiflora `Jane', Buxus sempervirens `Vardar Valley', and Taxus × media `Hicksii', where control of surface rooting was significant but moderate. Copper paint did not inhibit growth of stolons or rhizomes, which morphologically are stem structures. No visual signs of copper toxicity were observed, nor were there any differences in shoot growth.
COMPARISON OF ROOTS OF THREE MICROPROPAGATED CLONES OF PRUNUS SEROTINA VAR. VIRENS GROWN IN TWO SIZES OF CONTAINERS USING IMAGE ANALYSIS
Authors: Oddiraju Venu G. , Beyl Caula A.
Published: April 2024

Three different lines of Chisos cherry obtained from trees with profuse or scant root systems were grown in either 2 or 3 liter containers to determine if the effects of container volume could be detected as early as 12 weeks. The root characteristics (profuse or scant root development) seen in the parent material were not shared by the clonal propagules from those lines. There was a significant effect of the clone on surface area of fine roots, coarse to fine root ratio, and root dry weight (P<0.05) and on surface area of coarse roots (P<0.1). The smaller container reduced root dry weight significantly (P<0.1) and coarse to fine root ratio (P<0.05). Using an image capture and analysis system (ICAS) to classify and quantify the roots of the microcuttings, an effect of container volume could be detected even though the experiment was terminated only 3 weeks after roots had encountered the container walls and began exhibiting a coiling response.
ROOT GROWTH OF SEEDLINGS AND MICROCUTTINGS OF PRUNUS SEROTINA VAR. VIRENS AS A FUNCTION OF COMPACTION
Authors: Oddiraju Venu G. , Beyl Caula A.
Published: April 2024

Chisos cherry seedlings and microcuttings of two lines, one characterized by a profuse and the other a scant root system, were grown in compacted soils to study differences in their root development using an Image Capture and Analysis System (ICAS). Seedlings and microcuttings showed significant difference with respect to coarse root surface area, fine root surface area and root dry weight before they were placed under different compaction treatments (P<0.05). When final observations were made at 30 weeks, the compaction significantly restricted the growth of surface area of coarse roots and root dry weight (P<0.05) but not surface area of fine roots. Relative growth of coarse root surface area and dry weight in noncompacted soil was higher (P<0.05) than in compacted soil. Differences in coarse root and fine root surface area observed initially between seedlings and microcuttings disappeared over time.
INFLUENCE OF SPACING ON CUT FLOWER AND CUT STEM PRODUCTION OF FIELD-GROWN SALIX AND BUDDLEIA.
Authors: Armitage Allan M. , Dirr Michael A.
Published: April 2024

Plants of Salix alba `Britzensis' and Salix chaenomeloides were planted on 30, 60 or 90 cm centers in spring, 1992 and plants of Buddleia davidii `Black Knight' were planted at densities of approximately 45, 80, or 165 cm centers in fall, 1991. Stems of Buddleia were harvested in the summer and fall of 1992 and those of Salix were harvested in the winter of 1993. The number of stems/plant decreased but the number of stems/m2 increased with increasing plant density in all species. The stems of Salix alba `Britzensis' were significantly longer in the highest plant density.
EFFECT OF GRAIN SORGHUM ON GERMINATION OF WEED AND CROP SEEDS
Authors: Hoffman M. L. , Weston L. A.
Published: April 2024

Sorghum species are frequently used by horticultural producers as cover crops or green manures. Grain sorghum cover crops are often used in the southern United States. These summer annual grasses grow rapidly producing large quantities of biomass that has been shown to suppress weeds. Although allelochemicals in the roots and shoots have been identified, the precise mode of weed suppression has not been clearly elucidated. We performed a series of studies to evaluate the effect of sorghum on the germination of various weed and crop seeds. Petri dish assays were used to test the effect of germinating sorghum seed on the indicator species. Treatments were arranged in a completely randomized design with 4 replications and 2 experimental runs. Data collected included % germination as well as radicle and hypocotyl length. A modified Parker bioassay using 4 and 8 week old sorghum root and shoot tissue was used to study the effects of sorghum tissue on seed germination of the indicator species. Sorghum residue was observed to inhibit weed and crop seedling growth resulting in chlorosis of susceptible species.
GROWTH OF RUSSETTED AND ROUND-WHITE POTATO OVER TIME AND MOISTURE REGIMES
Authors: Sterrett S. B. , Savage C. P.
Published: April 2024

Marketing opportunities exist for russetted potatoes harvested during July and August, but commercial production has not been economically feasible because of inadequate tuber enlargement. Distribution of dry matter between source and sink was compared over time for russetted and round-white cultivars under two moisture regimes in field trials for two years. Dry matter accumulation in above-ground (stems and leaves) and below-ground (roots and tubers) portions of round-white cultivars occurred significantly earlier than in russetted cultivars. Shoot-root ratios of round-white cultivars exceeded those of russets, indicating reduced yield potential for russetted cultivars in this growing area. Results also suggest that inadequate size distribution to meet marketing demands cannot be overcome by adjusting moisture regimes with the currently available russetted clones.
VEGETATIVE GROWTH OF POTATO UNDER SON AGRO HIGH-PRESSURE SODIUM, HIGH-PRESSURE SODIUM, AND METAL HALIDE LAMPS
Authors: Yorio N.C. , Mackowiak C.L. , Wheeler R.M. , Sager J.C.
Published: April 2024

The vegetative growth of potato (Solanum tuberosum L.) cvs. Norland (NL) and Denali (DN) was investigated comparing SONAGRO high-pressure sodium (HPS-S), standard high-pressure sodium (HPS), and metal halide (MH) lamps. Plants were initiated from nodal culture and grown hydroponically in a reach-in growth chamber for 35 d with a 12-hr light/12-hr dark photoperiod and corresponding thermoperiod of 20/16 C. PPF for each treatment was maintained at 300 μmol m-2 s-1 and CO2 levels maintained at l000 μmol mol-1 to promote growth. Results showed that main stem length (SL) and number of internodes (INT) for DN were significantly higher under HPS compared to MH, while HPS-S was not significantly different from the other lamp types. Total dry weight (TDW) of NL plants was significantly higher for HPS than for either HPS-S and MH, however there was no significant difference in SL and INT among lamp types. The data suggest that the 12.6% increase in blue light (400-500 nm) with HPS-S in comparison to conventional HPS lamps may not be sufficient to consistently decrease the stem elongation effects commonly seen with plants grown under HPS.
EFFECT OF NITROGEN AND SULFUR FERTILIZATION ON THE CHEMICAL COMPONENTS OF FLAVOR IN SHRUNKEN-2 SWEET CORN
Authors: Wong A. D. , Swiader J. M. , Juvik J. J.
Published: April 2024

Dimethyl sulfide (DMS), the compound responsible for the characteristic “corny” aroma, and sugar are the principle chemical components of flavor in sweet corn. It was our contention that it may be possible to enhance the flavor potential of some high-sugar sweet corn hybrids by supplying increased amounts of N and S fertilizer to the crop to increase kernel DMS and sugar content. A factorial combination of two N (168, 310 kg/ha) and three S rates (0, 34, 101 kg/ha) was applied to six sh-2 sweet corn hybrids in a Plainfield sand. Kernel DMS and sugar levels were assayed over a period ranging from 20 to 29 days after pollination. In each case, kernel DMS and sugars decreased with increasing harvest maturity. In three hybrids, there was a positive response in kernel DMS to either N or both N-S. Kernel fructose and glucose concentrations tended to decrease as N fertilization rate increased, while sucrose levels remained relatively constant. In all hybrids, S fertilization had no effect on kernel sugars. The results indicated that it may be possible to increase kernel DMS potential in some genotypes by increased N fertilization, and to a lesser degree, from S application.
UTILIZING POULTRY LITTER AS A FERTILIZER: SWEET CORN YIELD MINERAL NUTRITION, AND SOIL CHEMISTRY
Authors: Earhart D. R. , Haby V. A. , Baker M. L.
Published: April 2024

Composted poultry litter (PL) containing 2.98% N was hand-applied to plots in a split-plot design with 3 replications. Application frequency (total, split) was the major plot and rate (0, 10.9, 21.7, and 43.6 Mg·ha-1) was the sub-plot. Rate was based on total N content of the PL and N requirement for maximum sweet com production. Comparisons were made with a fertilizer blend (FB) containing 23.8N-4.3P-4.1K at a total rate of 564 kg·ha-1 in split applications. Leaf area and average ear weight of sweet com ('Merit') were not affected by frequency or rate. Increasing PL rate from 10.9 Mg·ha-1 to 21.2 Mg·ha-1 increased yield by 3128 kg·ha-1. An increase to 43.6 Mg·ha-1 decreased yield which was probably due to an observed reduction in plant stand. When comparing FB with 10.9 Mg·ha-1PL, the yields were equal. Plant P and K concentrations were increased linearly by PL rate. There were no differences in % N or mg·kg-1Ca and Mg. The highest soil N03-N concentrations in the 15- to 30-cm depth range were produced by 43.6 Mg·ha-1PL (15 mg·kg-1 and FB (35 mg·kg-1. Only the high litter rate increased soil NO3-N below 30 cm As PL rate increased, there was a corresponding increase in soil P. There was a linear increase in soil K from 60 to 200 mg·kg-1 as rate increased. A linear decrease in pH was noted when PL rate increased. Soil EC was almost 2 times higher in the 43.6 Mg·ha-1 PL plots than the next highest rate (275 vs. 150 umhos·cm-1).
C3 AND C4 PLANT RESPONSES TO PHOSPHORUS-LIMITING ENVIRONMENTS
Authors: Halsted Marilou , Lynch Jonathan
Published: April 2024

The anatomical and biochemical characteristics of C4 plants may make them more efficient than C3 plants in nutrient deficient environments. A greenhouse pot study was conducted in the summer of 1992 to compare the responses of six C3, four C4 and two C3-C4 intermediate species to three levels of phosphorus nutrition: adequate, deficient, and severely deficient. Severely deficient P nutrition reduced shoot weight by 74% and 85% on average in the C3 and C4 species, respectively. C3 plants appear to be more efficient than the C4 in producing shoot biomass under stressful P conditions and two genera having C3, C4 and C3-C4 intermediate species exhibited a trend in the order of C4(least efficient) C3-C4 intermediate, C3 (most efficient). P nutrition was more significant than species or plant type in determining both the concentration of P in plant tissues and the carbon dioxide exchange rate (CER). A more detailed study is underway to compare biomass partitioning and P allocation schemes of these C3 and C4 and C3-C4 intermediate type plants.
LIGHT INTENSITY AND DROUGHT AS PREDISPOSITION FACTORS FOR DOGWOOD ANTHRACNOSE
Authors: Erbaugh Dan , Windham Mark , Stodola Ann , Augé Robert
Published: April 2024

Environmental factors regulating spread of dogwood anthracnose remain largely unstudied, so we conducted a two-year experiment to determine if light intensity or drought can affect this disease. After leaf emergence in 1990, two-year-old potted dogwood trees (Cornus florida L.) were placed outdoors in shade huts giving light treatments of 100%, 50%, 10% or 2% ambient light. One year later, trees were removed from huts to inoculate them (artificially or naturally) with Discula destructiva Redlin sp. Nov. After inoculation, trees were returned to their former light treatments and some of the trees were subjected to drought. Disease progression, quantified as increasing percentage of leaves with lesions, was unaffected by inoculation procedure. Light did affect the disease; by the end of the experiment, disease percentages in well-watered trees were 30% at 10% light, 15% at 2% light and below 5% at 100% and at 50% light. Drought increased disease progression on all shaded trees, ultimately 8x at 50% light, 1.4x at 10% light and 2x at 2% light.
ACTIVE OSMOTIC ADJUSTMENT: EFFECT ON CHANGES IN SORBITOL AND OTHER CARBOHYDRATES IN LEAVES, ROOTS AND STEMS OF APPLE
Authors: Wang Zhongchun , Quebedeaux Bruno , Stutte Gary
Published: April 2024

Potted `Jonathan' apple trees were subjected to water stress in a greenhouse. Midday leaf water potential (Ψw), osmotic potential (Ψs), and carbohydrates of various plant parts were measured to determine whether active osmotic adjustment occurred and its impact on carbohydrates. Mature leaves had the highest soluble sugar levels (74 mg/ml sap) and the lowest Ψs (-1.85 MPa), followed by young leaves (-1.58), stems (-1.02), and roots (-0.87). Sorbitol (sor) concentrations in young leaves, stems, and roots were 57, 28, and 27% of that in mature leaves. The concentrations of sucrose (suc), glucose, and fructose in young leaves, however, were 27, 35, and 146% higher than that in mature leaves. When Ψw decreased from -1.0 to -3.2 MPa, active adjustments of 0.3 MPa were observed in mature leaves, stems and roots while an adjustment of 1.0 MPa was detected in young leaves. As water stress developed, sor increased and suc and starch decreased in mature leaves and stems. In contrast, the roots had a significant increase in suc but a decrease in sor. Both suc and sor increased in young leaves under water stress. The physiological significance of carbohydrate changes in various tissues under water stress will be discussed.
PHOTOSYNTHESIS, WATER RELATIONS AND GROWTH RESPONSES OF GREENHOUSE TOMATO PLANTS TO HIGH-SOLUTION ELECTRIC CONDUCTIVITY AND LOW SOIL WATER CONTENT: SOIL WATER DEFICIT ACCLIMATION AND SALT BUILD-UP EFFECT
Authors: Xu Hui-lian , Gauthier Laurent , Gosselin André
Published: April 2024

Greenhouse tomato plants (cv. Capello) were grown in peat moss based substrate and treated with high and low nutrient solution electric conductivity (EC) under high (95±5%) and low (55±8%) soil water conditions. Photosynthesis (Pn) was decreased about 25% 1 day after soil water content reached 55%. However, as the soil water deficit was prolonged, the effect of water deficit diminished, with the decreasing extent of ca 15% on the 11th and 16th days from starting treatments. This suggested that tomato plants acclimated to soil water deficit. One day after soil water content reached 55%, leaf turgor potential (TP) decreased largely as leaf water potential (WP) dropped. However, as soil water level was kept constant for a period, TP recovered to a quite large extent even at the same WP level. This TP recovery accounted for the photosynthetic recovery. Drying the constantly well watered plants to the same soil water level decreased Pn to a much larger extent than did the prolonged soil water deficit. This supports the above-mentioned photosynthetic acclimation. The effects of high EC were not observed 1 day after the treatments started, but became larger and larger as the treatments were prolonged. Build-up of EC in the soil accounted for this result
EFFECTS OF DROUGHT STRESS ON PICLORAM UPTAKE, TRANSLOCATION AND EFFICACY IN RUSSIAN KNAPWEED (Centaurea repens L.)
Authors: Morrison R.G. , Lownds N.K. , Sterling T.M.
Published: April 2024

Picloram uptake, translocation and efficacy were studied using greenhouse-grown Russian knapweed plants. 14C-picloram was applied as individual droplets to the adaxial surface and uptake and translocation following 24 or 96 hr quantified with liquid scintillation spectroscopy. For efficacy studies, whole plants were sprayed. Drought stress was induced by withholding water and subsequently irrigating plants at 40% of pot capacity. Drought stress was quantified using a pressure bomb. Picloram uptake into watered plants (-0.50 MPa) averaged 10% of applied and did not change under drought stress. Of the picloram absorbed, about 8% was translocated in watered plants with equal amounts acropetal and basipetal. Drought stress (-1.22 MPa or greater) reduced picloram translocation 50 to 75% and increased basipetal translocation to about 80% of the total translocated. Picloram efficacy, measured as plant mortality or reduction in fresh weight, was greater in watered plants.
PRIMING AND ENVIRONMENTAL INFLUENCES ON GERMINATION OF TWO WOODY SPECIES
Authors: Davis Gregory L. , Hensley David L. , Wiest Steven C.
Published: April 2024

Osmoconditioning was examined as a presowing seed treatment for its influence on germination, rate of germination, and initial seedling root growth in seeds of A morpha fruticosa L. (imbibed for 48 hrs) and Hippophae rhamnoides L. (imbibed for 18 hrs) at 25C. Based on preliminary studies, seeds were imbibed in one of five osmotic solutions (0, -0.2, -0.7, -1.5, or -3.0 MPa) prepared with polyethylene glycol-8000. Seeds were then sown in test tubes containing plugs of Oasis growing medium saturated with osmotic solutions of no drought (0 MPa) or drought (-1.0 MPa) conditions at 15-35C. Root growth was measured with an image analysis system. Total root growth per seedling was less for both species in drought conditions regardless of temperature. Presowing treatments did not produce large differences in germination or rate of germination in either species.
SEASONAL CHANGES ON THE QUALITY OF `PERLETTE' TABLE GRAPES IN RESPONSE TO WATER-DEFICIT STRESS AT PARTICULAR STAGES OF DEVELOPMENT.
Authors: Siller-Cepeda Jorge , Osorio G. , Báez M. , Bringas E. , Sanchez A. , Avalos J.
Published: April 2024

The nature of yield and quality losses for many fruits is dependent upon the time when water deficits occur in relation to fruit development. We evaluated the water stress effect applied at different stages of development on the quality and harvest date of 'Perlette' table grapes. Nine treatments based on amount of water applied by the grower (100%, 80% and 60%) and their combinations at two growth stages, fruit set to vérasion (F-V) and vérasion to harvest (V-H) were compared. Weekly samples of fruit were analyzed for diameter, weight, volume, soluble solids, tritatable acidity, pH, and pectin content. Harvest percentage at each date was used as precocity index. Significant differences were found on diameter and weight among treatments at various stages of development. The earliest and highest harvest percentage was for (F-V 80% and V-H 100%) treatment. High °Brix were obtained when the water volume was reduced after vérasion, but quality was poor. Chelator soluble pectins represented > 90% of total soluble pectins and was higher on the treatment (F-V 60% and V-H 60%) at harvest.
DIURNAL PATTERN OF ADP-GLUCOSE PYROPHOSPHORYLASE ACTIVITY IN TOMATO
Authors: Logendra Sitheswary , Janes Harry W.
Published: April 2024

The diurnal pattern of the activity of the starch synthesízing enzyme ADP-glucose Pyrophosphorylase was studied in young tomato seedlings, grown under a light/dark cycle of 12h/12h. The third leaf from the base of the plant was used for the study when they were 80 to 90% fully expanded. The enzyme activity had two peaks, a smaller peak during the light period and a larger peak during the dark period. The activity began to increase before the lights were turned on and it was maintained for the first four hours of the light period and then began to decline. Similarly, the activity began to increase again before the lights were turned off and remained high for the first four hours of the dark period.
PHOTOSYNTHETIC CAPACITY, PHOTOPERIOD, AND SHOOT ELONGATION OF HARDY EVERGREEN AZALEAS (RHODODENDRON) CULTIVARS
Authors: Ballantyne David J.
Published: April 2024

In a June-July greenhouse experiment photosynthetic capacity (Pcap) and shoot elongation were determined for 13 azalea cultivars. While the positive correlation between shoot elongation and Pcap was relatively low, the 2 cultivars with the highest rate of shoot elongation (`Treasure' and `Noordthiana') had the highest Pcap. In October-January greenhouse experiments, `Treasure and `Noordthiana' had highest rates of shoot elongation, but only `Treasure' had a high Pcap and `Noordthiana' had a very low Pcap. A growth chamber experiment showed that while long days stimulated shoot growth (compared to short days) they had no influence on Pcap. Gibberellin sprays stimulated shoot growth of `Vuyk's Scarlet' in the greenhouse during June-July but had no effect on Pcap. During November-January in the greenhouse long days stimulated shoot growth and in both summer and winter periods production time of cultivars with a rapid rate of shoot elongation was considerably less than for slower-growing cultivars, although rates of shoot elongation were much slower during winter periods.
COMPARISON OF FOUR METHODS FOR ESTIMATING TOTAL LIGHT INTERCEPTION BY TREES OF VARYING FORMS.
Authors: Wünsche Jens N. , Lakso Alan N. , Robinson Terence L. , Denning Steven S.
Published: April 2024

The objectives of this study were to: (1) compare four methods of estimating daily light interception (fisheye photography with image analysis, multiple light sensors, ceptometer and point grid) with various apple tree forms (Slender Spindle, Y- and T-trellises and vertical Palmette) and (2) evaluate the interaction of tree form, time of day and atmospheric conditions on light interception. All methods were highly correlated to each other (R2≥92%) for estimated daily mean % total light interception by the various tree forms. Fisheye photography, ceptometer and sensor generated almost equal daily mean values of intercepted light by each tree form, whereas by using point grid values were slightly lower. Interactions of tree form, time of the day and diffuse/direct radiation on estimated light interception were found. Under overcast skies, daily variations in total light interception were small for all tree forms. Under clear skies, the time-of-day effect on light interception strongly increased from horizontal to vertical tree canopies, indicating the importance of multiple readings in upright canopies. All methods had advantages and disadvantages, but the good results obtained by using the rapid, inexpensive point grid method (counting of shaded points on sheet under canopy) on clear days may allow estimates of orchard light interception when other methods are too costly and/or time-consuming.
INFLUENCE OF BORON NUTRITION ON PHOTOSYNTHESIS AND STOMATA CONDUCTANCE OF OILSEED RAPE
Authors: Kennedy Larry S. , Sams Carl E. , Lewis Russell J.
Published: April 2024

Rape (Brassica napua var. oleifera) plants were grown in a continually circulating hydroponic system with perlite as the root support medium. Two experiments (I and II) were supplied with complete nutrient solutions (modified Hoaglands) differing only in added boron ((I) 0.40 (normal), 0.20, or 0.04 mg L-1, and (II) 0.40, 0.02, or <0.01 mg L-1). A minimum of nine replications was examined in each experiment. Photosynthesis (Pn) and stomatal conductance (SC) readings were taken on leaves 8, 12, 16, 20, and 24 when the leaves attained 70% to 90% full expansion ((I) days 58, 76, 86, 97, 106 and (II) days 50, 70, 78, 88, and 97 respectively following planting dates). Measurements were taken at solar noon (± two hours) using a portable Pn analyzer (Analytical Development Company). Rape plants in experiment I appeared morphologically similar, did not exhibit B deficiency symptoms, and did not have significant Pn or SC. Morphological development of plants in experiment II varied widely among treatments. Photosynthesis and/or SC mean values were significantly reduced at leaf stages 16 to 24 as B availability decreased. Treatment contrasts within and between experiments suggest that the 0.02 to 0.04 mg L-1 range of added B is critical for the development of normal Pn and SC in leaves. These findings support our previous research report that the natural ontogeny of oilseed rape is greatly affected within a narrow range of B availability.
613 (PS 3) SUCROSE SYNTHASE LOCALIZATION DURING SEED AND HAIR DEVELOPMENT: COTTON OVULES AS A MODEL SYSTEM
Authors: Vinci J. , Nolte K.D. , Koch K.E. , Hendrix D.L. , Radin J.W.
Published: April 2024

Immunolocalization of sucrose synthase in cotton ovules was conducted to clarify the relationship between this enzyme and sucrose import during seed and hair development. Although rapidly growing plant organs are known to have high activities of sucrose synthase, information on specific localization has been minimal at the cell level. Cotton ovules were examined in the present work as representatives of developing dicot seeds, and because their expanding hairs would have a locally high demand for cell wall synthesis. Initial analyses focused on ovules immediately before and after anthesis/pollination. Heavy immunolabel was observed solely in the nucellar tissue 1 day before anthesis. Immediately following anthesis/pollination, however, sucrose synthase became evident in cells of the external (but not internal) integument, expanding from the chalazal to micropylar end of this tissue. Little sucrose synthase was directly associated with very young epidermal hairs prior to their most rapid expansion. Immunolabel appeared to be localized in cells associated with the vascular bundle of this external integument. The shift in spatial/temporal localization of sucrose synthase in cotton ovules following pollination indicates a close association between sucrose synthase and probable sites of sucrose import at a cellular level during early seed development.
614 (PS 3) DAYLILY RESPONSE TO PLANT BIOSTIMULANTS
Authors: Aldrich James H. , Norcini Jeffrey G.
Published: April 2024

Application of plant biostimulants to various crops has enhanced yields and increased growth. This study was conducted to determine the effect of plant biostimulants on growth of Hemerocallis × `Aztec Gold'. Roots of single-plant divisions were immersed for 5 min in solutions of 520 ppm KELPAK (seaweed concentrate), 390 ppm PGR IV (hormone concentrate containing nutrients), 250 ppm AGRI-GRO (contains dormant nitrogen-fixing bacteria) + 250 ppm molasses, or water prior to planting on 20 April 1992. Plants were grown in 3.8-liter containers under 31% shade. Foliar sprays (to wet) of these biostimulants (same concentrations as before) were applied on 20 May, 19 June, and 13 August 1992. Plants were harvested on 21 October 1992. None of the biostimulants affected final plant height, number of divisions, or shoot and root fresh and dry weights. However, plants treated with KELPAK had higher shoot to root ratios (fresh and dry weight) compared to the control.
619 (PS 3) EVALUATION OF SEED GERANIUM CULTIVARS FOR THE LANDSCAPE
Authors: Howe T. K. , Waters W. E.
Published: April 2024

Seed geranium (Pelargonium × hortorum) cultivars were evaluated based on days to flower, flower and umbel diameter, flower color, plant dimensions, uniformity, appearance, longevity and florierousness during the spring and fall of 1992. Spring: Days from sowing to flower for 60 cultivars ranged from 96 to 115 days. `Tetra Scarlet' was significantly later to flower than all other cultivars except `Orange Appeal' which flowered at 112 days. Plant height ranged from 24.4 to 38.4 cm. `Pinto White' was taller than all other cultivars except `Tetra Scarlet' and `Pinto Bicolor'. Umbel diameter ranged from 9.4 cm to 14.0 cm. `Freckles' had the largest umbel diameter. At 111 days after sowing, umbel number ranged from 1.0-11.5, with `Multibloom Salmon' and `Multibloom Pink' producing the most. Fall: Days from sowing to flower for 62 cultivars ranged from 85 to 136 days. `Orange Appeal' flowered later than any other cultivar, followed by `Tetra Scarlet' at 119 days; also significantly different than any other cultivar. Mature plant height ranged from 25.5 to 42.3 cm. `Pinto White' was taller than 41 other cultivars. Umbel diameter ranged from 8.3 to 13.2 cm.
621 (PS 3) EFFECT OF CONTRASTING PRODUCTION LOCATION ON LEAF MORPHOLOGY OF TWO LANDSCAPE SHRUBS
Authors: Martin Chris A. , Sharp William P. , Ruter John M. , Garcia Richard L.
Published: April 2024

Same-source rooted cuttings of Feijoa Sellowiana Hort. and Ligustrum japonicum L. were grown under identical production systems in Tempe, AZ, USA or Tifton, GA, USA during the Spring and Summer 1992. Leaf area was largest and specific leaf weight was lowest for all Georgia-grown plants. Scanning electron microscopy revealed that Arizona Feijoa leaves had trichomes on both the abaxial and adaxial leaf surfaces, whereas, leaves of Georgia Feijoa had trichomes on the abaxial surface only. Arizona Feijoa leaves also had increased abaxial surface pubescence compared to leaves of Georgia Feijoa. Both Feijoa and Ligustrum grown in Arizona had a higher density of palisade and spongy mesophyll cell layers compared to their Georgia counterparts. When placed under the same irradiance source, adaxial leaf surface temperatures of Georgia-grown Ligustrum and Feijoa were approximately 4.2 and 0.2C, respectively, higher than for those grown in Arizona. Higher leaf temperatures of Georgia-grown plants were correlated with darker leaf color compared to the Arizona-grown plants.
623 (PS 3) GROWTH AND NUTRIENT DYNAMICS IN ILEX CRENATA THUNB. `HELLERI' ACROSS AN ALUMINUM GRADIENT
Authors: Lasseigne F. Todd , Smalley Timothy J. , Mills Harry A. , Miller William P.
Published: April 2024

Ilex crenata `Helleri' (Helleri holly) can experience landscape establishment problems in the Southeast. Since aluminum toxicity is a major problem in acid soils of the Southeast, this experiment studied the effects of aluminum on Helleri holly grown in solution culture. A modified Hoagland's solution contained low phosphorus concentrations (32 μm), a 1:1 NH4+:NO3- nitrogen ratio, and aluminum treatments consisting of 0, 222, 444, 889, and 1332 μm Al supplied at equal ratios from AlCl3·6H2O and Al2(SO4)3·18H2O. The MINTEQA2 (version 3.11) chemical speciation model was used to predict activity of ions in solution. Shoot growth and root length were not affected by aluminum after 12 weeks in solution culture. Total plant nutrient uptake was monitored weekly. Preliminary results suggest that Helleri holly does not take up aluminum ions even though NH4+ is the preferred nitrogen source. Other studies have shown increased aluminum toxicity effects when NH4+ uptake exceeded NO3- uptake.