bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of Cell Wall Components in Normal and Disordered Juice Vesicles of Grapefruit
Authors: Hwang Yong-Soo , Huber D.J. , Albrigo L.G.
Published: January 2019

Cell wall composition and structure were examined in visually normal (N), granulated (G), and collapsed (VC) juice vesicles of `Marsh Seedless' grapefruit (Citrus paradisi) Macf.). According to gel-filtration data, VC appeared to be associated with a modification of water-soluble (WSP) and chelate-soluble (CSP) pectin molecular weight (Mr); small-Mr pectins increased, whereas large-J4. pectins decreased. The difference in M= of pectins did not appear to be mediated by polygalacturonases. Molecular weight of hemicelluloses did not differ. Granulated vesicles contained about two times more structural polysaccharides (pectins, hemicelhdose, and cellulose) than N vesicles, although hemicellulose and pectin M= modification were absent. Ion-exchange profiles of WSP, CSP, and hemicelhrlose fractions of VC and G vesicles were not different from those of N vesicles. Individual cells in vesicles with G and these vesicles themselves were much larger than those of N vesicles, whereas cells in VC were partially or completely collapsed.
Induction of Changes in Internal Gas Pressure of Bulky Plant Organs by Temperature Gradients
Authors: Corey Kenneth A. , Tan Zhi-Yi
Published: January 2019

Water manometers were connected to fruits of tomato (Lycopersicon esculentum Mill.) and pepper (Capsicum annuum L.), and then fruits were submerged in water baths providing initial temperature gradients between fruit and water of 0 to 19C. Apple (Malus domestics Borkh.) fruits, carrot (Daucus carota L.) roots, witloof chicory (Cichorium intybus L.) roots, rhubarb Rheum rhabarbarum L.) petioles, and pokeweed (Phytolacca americana L.) stems were subjected to water bath temperature gradients of 5C. Internal partial vacuums developed in all organs within minutes of imposing the gradients. The maximum partial vacuums in tomato and pepper fruits increased with increasing temperature gradients. Uptake of water accompanied changes in internal pressure reaching maxima of 17% (w/w) and 2% (w/w) of pepper and tomato fruits, respectively, after 22 hours. Maximum pressure changes achieved in bulky organs deviated from those predicted by the ideal gas law, possibly due to concomitant changes in gas pressure upon replacement of intercellular spaces with water and dissolution of CO2. Partial vacuums also developed in pepper fruits, rhubarb petioles, and pokeweed stems following exposure to air 15C cooler than initial organ temperatures. Results point to the role of temperature gradients in the transport of liquids and gases in plant organs.
In Vitro Propagation of Muscadine Grape by Axillary Shoot Proliferation
Authors: Lee Ni , Wetzstein Hazel Y.
Published: January 2019

Plantlets were recovered from axillary bud cultures of muscadine grape (Vitis rotundifolia, `Summit'). Nodal segments 0.5 to 1.0 cm long were cultured in Murashige and Skoog (MS) basal medium supplemented with 5, 10, 20, or 40 μm BA. Best total shoot production was obtained with 10 μm BA; with higher BA levels, shoots were unexpanded and exhibited high mortalities. MS medium supplemented with IBA enhanced rooting by increasing rooting percentage and number per plantlet. Shoots previously proliferated on medium with 5 μm BA rooted significantly better than those multiplied on 10 μM BA. Shoot vigor during rooting was greater in shoots proliferated on 5 vs. 10 μm BA. Root development was not significantly affected by liquid vs. agar-solidifted medium or shoot length. Chemical names used: N-(phenylmethyl) -1H-purin-6-amine (BA), 1H-indole-3-butyric acid (IBA).
Micropropagation of Members of the Cactaceae Subtribe Cactinae
Authors: Clayton Philip W. , Hubstenberger John F. , Phillips Gregory C. , Butler-Nance S. Ann
Published: January 2019

Micropropagation of 11 rare or endangered cacti species belonging to the subtribe Cactinae was achieved by rooting of proliferated axillary shoots. Shoot tip explants were obtained from seedlings of Escobaria missouriensis D.R. Hunt, E. robbinsorum (Earle) D.R. Hunt, Sclerocactus spinosior (Engelm.) Woodruff & L. Benson, and Toumeya papyracantha (Engelm.) Br. & Rose, and from mature plants of Mammillaria wrightii Engelm., Pediocactus bradyi L. Benson, P. despainii Welsh & Goodrich, P. knowltonii L. Benson, P. paradinei B.W. Benson, P. winkleri Heil, and S. mesae-verdae (Boissevain) L. Benson. Three or four species were used in each of a series of experiments investigating the effects of basal media and auxin and cytokinin types and concentrations on axillary shoot proliferation. Low or no auxin but moderate to high cytokinin concentrations were required for axillary shoot production. All species rooted spontaneously on hormone-free media; however, several species rooted better on media containing auxin. All species were re-established in the greenhouse.
The Fate of Urea in a Sphagnum Peat Medium as Affected by Lime Source and Rate
Authors: Vetanovetz Richard P. , Peterson John C.
Published: January 2019

Sphagnum peat was blended with CaCO3 or Ca(OH)2 and incubated for 3 weeks at 20C to achieve a pH of ≈ 4.4, 5.4, 6.2, or 7.3. An unlimed control had an initial pH of 3.5. Urea was added to medium treatments at the rate of 125 μg urea-N/cm3. Samples were incubated at 20 ± 1.0C. Medium pH, urea-N, \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{NO}_{2}^{-}-\mathrm{N}\) \end{document}, and \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{NO}_{3}^{-}\mathrm{N}\) \end{document} were measured immediately before urea addition (day 0) and 1, 2, 3, 4, 7, 14, 21, and 28 days after urea addition. Medium pH increased when urea was applied for all lime treatments. Medium pH remained at an elevated level, except for the two highest rates of C&CO3, in which pH increased Initially, then decreased. The rate of urea hydrolysis increased as lime rate increased. For both lime sources, urea was completely hydrolyzed within 4 days for the two highest lime rates, except for the highest rate of CaCO3. Nitrite accumulation was evident in the highest lime rate for both lime sources. Nitrate formation was greater with CaCO3 than with Ca(OH)2.
Harvest Maturity and Concentration and Exposure Time to Acetylene Influence Initiation of Ripening in Mangos
Authors: Medlicott A.P. , N'Diaye Mayé , Sigrist J.M.M.
Published: January 2019

The effects of acetylene at 0, 0.1, 0.2, 0.4, 0.8, or 1.6 ml·liter-1 and exposures of 4, 8, 12, or 24 hours on ripening initiation In mangos (Mangifera indica L.) harvested at three stages of maturity were investigated: Ripeness was assessed before and after treatment in `Tommy Atkins', `Ruby', and `Amelie' mangos by analysis of texture, peel, and pulp color development, soluble solids concentration, and pH. The initiation of ripening depended on the acetylene concentration, exposure time to acetylene, the physiological maturity of the fruit at harvest, and on the cultivar. Changes that can occur during ripening bad different sensitivities to acetylene gas. Acetylene treatment of 0.1 or 0.2 ml·liter-1 for 24 hours at 25C initiated softening, but had no effect on the other ripening processes measured. All the ripening changes measured were initiated with a 24-hour exposure to 0.4 ml·liter-1 in `Tommy Atkins', while 0.8 ml·liter-l was required with `Ruby' mangos. There was an interaction between gas concentration and exposure time taken to Initiate ripening. The 0.8 ml·liter-1 acetylene treatment required 24 hours to initiate full ripening, while 8 hours were required with 1.6 ml·liter-l acetylene and 1.0 ml·liter-1 ethylene. Mature and half-mature fruit showed a similar response to gas treatments; immature fruit failed to show full ripening initiation, although softening and peel color development were enhanced.
Chemical Changes in Okra Stored in Air and Controlled Atmosphere
Authors: Baxter Lawford , Waters Luther
Published: January 2019

Okra (Abelmoschus esculentus L. Moench) pods stored In a controlled atmosphere (CA) of 5% O2 and 10% CO2 at 11 ± 1C and in air at the same temperature (RA) were compared to determine the effects of the two storage environments on changes in sugars, organic acids, proteins and amino acids, and ascorbic acid contents within the tissue. Pods were sampled at 3-day intervals for 12 days. CA-stored pods generally had greater retention of sugars, soluble proteins, and amino acids than RA-stored pods. Citric, malic, and ascorbic acids contents of CA pods also declined more slowly than those of RA pods.
Herbicide Effects on Bermudagrass Lawn Recovery and Crabgrass Control during Spring Root Decline in the North-South Transition Zone
Authors: Callahan Lloyd M. , High Joe W.
Published: January 2019

A bermudagrass [Cynodon dactylon (L) Pers. × C. transvaalensis Burtt-Davy `Tifgreen'] lawn in the transition zone (about lat. 35°N) was treated in late March for 3 years with a high and a low level each of benefin, bensulide, DCPA, oxadiazon, and siduron. Objectives were to determine if relationships exist between field environment and dates of preemergence herbicide applications for large crabgrass (Digitaria sanguinalis L. Scop.) control, the spring root decline (SRD) phenomenon, and herbicide phytotoxicity to the bermudagrass. Herbicide treatments in late March generally controlled large crabgrass, reduced total weed competition, and appeared to aid bermudagrass spring growth following winter dormancy. Herbicide injury to `Tifgreen' bermudagrass roots during SRD does occur under practical field conditions and was more severe when bermudagrass spring green-up occurred closer to the herbicide treatment date, as in 1982. Bermudagrass stand density was significantly reduced with the high level of siduron in 1980 and 1981, and with both levels of oxadiazon and siduron in 1982. Bensulide and oxadiazon, at both levels, gave 92% to 100% crabgrass control during all three treatment years. The high levels of benefin and DCPA in 1980, both levels of benefin and the high level of DCPA in 1981, and both levels of DCPA and the high level of benefin in 1982 gave crabgrass control in excess of 95%. Chemical names used: N-butyl-N-ethyl-2,6-dinitro-4-(trifluoromethyl)-benzenamine (benefin), O,O-bis(1-methylethyl)-S-[2-[(phenylsulfony l)-amino]ethyl] phosphorodithioate (bensulide), dimethyl 2,3,5,6-tetra-chloro-1,4-benzenedicarboxylate (DCPA), 3-[2,4-dichloro-5-(1-methylethoxy)phenyl]-5-(l,l-dimethylethyl)-l,3,4-oxadiazol-2 -(3H)-one (oxadiazon), N-(2-methylcyclohexyl)-N'-phenylurea (siduron).
Senescent Breakdown of `Jonathan' Apples in Relation to the Water-soluble Calcium Content of the Fruit Pulp before and after Storage
Authors: Saks Yolanta , Sonego Lilian , Ben-Arie Ruth
Published: January 2019

In `Jonathan' apples grown in Israel, the incidence of senescent breakdown after 5 months of storage at 0C was not correlated with total or water-soluble Ca content at harvest. Likewise, no other assayed component of the water-soluble or total mineral content (P, Mg, K) of the fruit pulp at harvest correlated with the disorder after storage. After storage, a general decrease in the solubility of Ca was observed. However, this decrease was not uniform in all fruit and, as a result, the correlation between water-soluble and total Ca content, which was high at harvest, diminished after storage. Water-extractable Ca from stored fruit was negatively correlated and water-soluble K/Ca was positively correlated with the incidence of senescent breakdown, whereas total Ca was not correlated.
Response of Seed Carrot to Various Water Regimes. I. Vegetative Growth and Plant Water Relations
Authors: Hutmacher R.B. , Steiner J.J. , Ayars J.E. , Mantel A.B. , Vail S.S.
Published: January 2019

The influence of irrigation frequency and the severity and rate of development of soil water deficits on the vegetative growth and water status of carrots (Daucus carota L. var. sativa DC.) grown for seed were investigated in a fine sandy loam soil. Beginning with the period of rapid development of primary umbels, various irrigation frequencies [daily vs. intervals corresponding to 30 mm of accumulated crop evapotranspiration (ETc)] were investigated at irrigation rates ranging from 40% to 120% of estimated ETC. The magnitude and rate of development of soil water deficits markedly influenced carrot responses to developing water deficits. Stomata] conductance and leaf water potential (LWP) measurements exhibited some potential for use in irrigation scheduling and were the most sensitive and consistent indicators of plant water status. Under low-frequency continuous-deficit irrigation, a combination of moderate reductions in stomatal conductance and major reductions in peak leaf area and late-season maintenance of viable leaf area occurred. These responses were effective water-conserving mechanisms, allowing growth at a reduced rate and continued development of viable seed. In contrast, rapid development of soil water deficits resulted in nearly complete stomatal closure, cessation of growth, and rapid reductions in leaf area.
Application of Plastochron Index to Common Bean Grown in Controlled Environments
Authors: Yourstone K.S. , Wallace D.H.
Published: January 2019

This study was undertaken to determine whether plastochron index (PI), a mathematical construct that quantifies shoot development, can be applied to indeterminate bean (Phaseolus vulgaris L.) genotypes. Length measurements of the middle trifoliate leaflet were the basis of the PI calculation. The expansion of each middle trifoliate leaflet at every node on each plant tested was measured over time to determine whether the growth pattern of each leaflet fits the assumptions of the PI construct. Plants from five indeterminate bean genotypes were grown in two controlled environments: A constant 29C with 12-hr of daylength, and a constant 23C with 12-hr daylength extended to 14 hr with low light intensity. Early leaflet expansion was exponential for all five genotypes in both environments. Expansion rates of successive leaflets were also similar, although a few leaflets in three of the 10 genotype-environment combinations differed in their rates of expansion. Exponential and equal rates of expansion validate the calculation of the fractional component of the PI. In both environments, all genotypes exhibited an increasing rate of leaf initiation with time, which precludes the use of a simple linear slope in estimating rate of development.
Response of a Sweet Corn × Tropical Maize Composite to Mass Selection for Temperate-zone Adaptation
Authors: Rubino David B. , Davis David W.
Published: January 2019

This study was conducted to investigate the effects of mild mass selection for adaptation on the performance, genotypic variance, combining ability, S1 family-testcross correlation, and midparent heterosis of S1 families derived from a sweet corn (su) × tropical maize (Zea mays L.) composite (Composite 1R). Four cycles of random mating followed by 10 cycles of 10% stratified mass selection were conducted for earliness, plant and ear type, and freedom from pests. Selection significantly (P < 0.01) decreased plant height, ear height, percentage barrenness, and ear length, and significantly (P < 0.01) increased stalk breakage, earliness (Celsius heat units to 50% anthesis and silking), and kernel row number of both S1 families and their testcrosses. Juvenile plant height at 45 days after planting increased in testcrosses only. Percentage tip blanking and pericarp thickness did not change. For most traits, the greatest response occurred during the first five of 10 selection cycles. Cycle 10 testcrosses performed at least as well as elite check testcrosses for eight of 10 traits. The tropical parents improved combining ability for increased juvenile plant height and kernel row number, and decreased percentage of stalk breakage. As a result of selection, genotypic variance among S families decreased by >40% for heat units to 50% anthesis and silking, ear height, and percentage of barrenness, although for all traits measured, significant genotypic variation persisted following 10 cycles of mass selection for adaptation. S1-testcross correlations and percentage midparent heterosis tended to be consistent across selection cycles. Five cycles of mild stratified mass selection increased the adaptation of a temperate sweet corn × tropical maize composite to the temperate zone of the United States while maintaining significant genotypic variation.
Inheritance and Assessment of Bentazon Herbicide Tolerance in `Santaka' Pepper
Authors: Fery Richard L. , Harrison Howard F.
Published: January 2019

Experiments were developed to study the inheritance of the high level of tolerance to the herbicide bentazon exhibited by the pepper (Capsicum annuum L.) cultivar Santaka. Parental, F1, F2, and backcross populations of the cross `Santaka' × `Keystone Resistant Giant' were evaluated for injury in a greenhouse test using bentazon at a rate of 4.5 kg·ha-1 (1.1 kg×ha-1 is the rate recommended for most applications). Additionally, parental and F1 populations were evaluated for injury under field conditions using sequential bentazon applications of 4.5, 4.5, 6.75, and 9.0 kg·ha-1. A single, dominant gene determined tolerance. F1 hybrid plants (heterozygous at the locus conditioning tolerance) exhibited a high level of tolerance under field conditions. Results of the greenhouse test suggested a possible cytoplasmic involvement in the expression of the tolerance gene, but the results of the field test provided strong evidence that cytoplasm does not play a significant role. We propose that this gene be designated Bentazon tolerance and symbolized Bzt. Chemical name used: 3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide (bentazon).
Ovule Culture to Obtain Progeny from Hybrid Seedless Bunch Grapes
Authors: Gray D.J. , Mortensen J.A. , Benton CM. , Durham R.E. , Moore G.A.
Published: January 2019

Ovules of seedless bunch grapes (Vitis spp.) fertilized by controlled pollination increased in size during berry development. More ovules cultured 10 days or 60 to 70 days after pollination became brown compared to those cultured at 20 to 40 days. Cultured ovules developed with and without endosperm. Globular to torpedo stage embryos were recovered. More embryos and plants were recovered from ovules cultured at 40 or 60 days than at 10 or 20 days after pollination. Pollen parent significantly affected both embryo and plant recovery at certain sampling times. BA incorporated into medium significantly increased embryo germination percentage. Electrophoretic analysis of glucosephosphate isomerase in progeny showed that 67% to 88% were hybrids of controlled crosses. Of four vines that fruited thus far, two were seedless. Seedless progeny had smaller seed traces than either parent. Chemical name used: N-(phenylmethyl) -1H-purin-6-amine (BA).
Modeling Plant Population and Rectangularity Effects on Broccoli Head Weights and Yield
Authors: Westcott M.P. , Callan N.W.
Published: January 2019

Broccoli (Brassica oleracea L. var. italica) head weights and yields are highly sensitive to plant densities (P) and rectangularity. Broccoli cultivars were grown at four plant spacings (2.2 to 8.6 plants/m2) and four N rates (O to 336 kg N/ha) in 1986 and 1987. In 1988, plug spacings, as above, were factorially combined with treatments of one, two, or three plants per plug. Head weight (w) data were fitted to the reciprocal model: 1/w = a + bp and the exponential model: w = AKP, where a, b, A, and K are constants. Nitrogen rate did not interact with p. In 1986 and 1987, both the reciprocal and exponential models fit the w data (expressed as w relative to wmax for each cultivar) with highly significant R2 values of 0.525 to 0.605. Yield equations derived from these models were asymptotic. In 1988, clumping (multiple plants per plug) reduced head weights but interacted with plant density. Only the exponential model could account for the assumption that clumping effects diminish as plant densities increase; the reciprocal model predicted the opposite effect. The exponential model was expanded to the form: w = CAKP, where C is proportionate reduction of w due to clumping. Derived yield models were asymptotic for the reciprocal model and parabolic for the exponential model.
The Role of Leaf Development on Anthurium Flower Growth
Authors: Dai Jingwei , Paull Robert E.
Published: January 2019

The growth and development of Anthurium andraeanum Andre cv. Kaumana flower before and after emergence from the subtending leaf base was studied. Eighty days before emergence, the anthurium flower was =0.3 cm long, enclosed by two tightly rolled stipules at the base of the subtending leaf petiole. During the rapid elongation stage of the leaf petiole, the flower (0.8 to 1.0 cm long) entered a period of slow growth 40 to 60 days before flower emergence. After the subtending leaf blade unfurled and had a positive photosynthetic rate, flower growth resumed. Spathe color development started =28 days before emergence when the flower was =50% of the emergence flower length (4.5 cm). At flower emergence, the spathe, excluding the lobes, was =75% red. The lobes did not develop full redness until 7 to 10 days after emergence. Peduncle growth was sigmoidal with the maximum growth rate 21 days after emergence. Spathe growth is characterized by a double sigmoid curve. The young, growing, subtending leaf blade had a negative net photosynthetic rate. Removal of this leaf blade advanced flower emergence by 18 days. The soft green leaf (25 to 30 days after leaf emergence) had a slightly positive measured net photosynthetic rate, and the removal of this leaf resulted in flower emergence 11 days earlier. A mature subtending leaf had the highest measured net photosynthetic rate, and its removal had little effect on flower emergence. The subtending leaf acted as a source of nutrients required for the developing flower. Altering the source-sink relationship by leaf removal accelerated flower emergence, probably by reducing the slow growth phase of the flower.
Response of Oxypetalum caeruleum to Irradiance, Temperature, and Photoperiod
Authors: Armitage A.M. , Seager N.G. , Warrington I.J. , Greer D.H. , Reyngoud J.
Published: January 2019

Incremental increases in temperature from 14 to 22 to 30C resulted in linear increases in stem length and node number and decreases in stem diameter and stem strength of Oxypetalum caeruleum (D. Don.) Decne. Higher temperatures also resulted in additional flower abortion, reduced time to flowering, and fewer flowering stems per inflorescence. Reduction in the photosynthetic photon flux (PPF) from 695 to 315 μmol·s-1·m-2 had similar effects as increasing the temperature on vegetative characteristics, but had little effect on reproductive ones. The rate of stem elongation was greatest at low PPF for all temperatures and at high temperature for all PPF treatments. Net photosynthesis rose between 14 and 22C and declined at 30C for all PPF treatments. Long photoperiods (12 or 14 hours) resulted in longer internodes, longer stems, and more flowers per cyme than short photoperiods (8 or 10 hours), but photoperiod had little effect on flowering time. Treatments to reduce latex coagulant and silver thiosulfate treatments had no significant effect on vase life.
Tree Nitrogen Status and Leaf Canopy Position Influence Postharvest Nitrogen Accumulation and Efflux from Pear Leaves
Authors: Sanchez Enrique E. , Righetti Timothy L.
Published: January 2019

`Cornice' pear trees (Pyrus communis L.) were fertilized with ammonium nitrate depleted in “N in Spring 1987 and 1988. In Aug., Oct., and Nov. 1988, midleaves on current season shoots were sampled at three positions from the periphery to the center of the canopy. Total N/cm' of leaf area remained almost constant through October, even though percent N concentration declined as specific leaf weight (SLW) increased. Furthermore, there was no substantial net change in either labeled or unlabeled N in either treatment until senescence began in October. Peripheral leaves contained higher levels of both reserve and newly acquired N than did less-exposed leaves. Despite large differences in N/cm2 for October samples, by November leaves from both high (HN) and low N (LN) trees exported similar percentages of their total N. The average N export to storage tissues irrespective of tree N status was 71%, 61%, and 52% for peripheral, medium, and interior leaves, respectively. The export of N was influenced more by the leaf position in the plant canopy than the nutritional status of the tree.
Storage Temperature and Ethylene Influence on Ripening of Papaya Fruit
Authors: An Jo-Feng , Paull Robert E.
Published: January 2019

The temperature and ethylene response of ripening papaya fruit (Carica papaya L. cv. Sunset) was determined with and without 14 days of storage at 10C. Temperatures at or higher than 30C adversely affected the quality of the ripe papaya. Papayas held at 32.5C for 10 days failed to ripen normally, as evidenced by poor color development, abnormal softening, surface pitting, and an occasional off-flavor. Skin yellowing, fruit softening, and flesh color of papayas exhibited a quadratic response to ripening time within the temperature range of 22.5 to 27.5C. Flesh color development of nonstored fruit did not change significantly during the first 6 days at ripening temperatures, then rapidly increased. Fruit stored for 14 days at 10C exhibited faster ripening rates (e.g., degreening and softening and no delay in flesh color development) than nonstored fruit when removed to other ripening temperatures (17.5 to 32.5 C). Problems of weight loss and development of external abnormalities were more significant at temperatures higher than 27.5C. The optimal temperature range was found to be between 22.5 and 27.5C, with fruit taking 10 to 18 days to reach full skin yellowing from color break, whether or not fruit was stored at 10C. Exogenously applied ethylene (=100 μl·liter-1) stimulated the rate of fruit ripening, as measured by more uniform skin yellowing and rate of flesh softening whether or not the fruit were stored for 14 days at 10C. Ethylene did not ripen immature papayas completely in terms of skin and flesh color development. The outer portion of the flesh of ethylene-treated fruit had a faster rate of ripening, as indicated by carotenoid development and softening rate, while the same area of the flesh was still pale white in nonethylene-treated fruit. Ethylene reduced the coefficient of variation for skin color, softening rate, and flesh color development in treated fruit. Ethylene increased the rate of skin degreening and hastened the rate of carotenoid development and softening in the outer mesocarp, while having little effect on the inner mesocarp.
Performance of `Orlando' Tangelo Trees on Ten Rootstocks in Arizona
Authors: Fallahi Esmaeil , Mousavi Zahra , Rodney D. Ross
Published: January 2019

The influence, of 10 rootstocks on growth, yield, and fruit quality of `Orlando' tangelo (Citrus paradisi Macf. × C. reticulata Blanco) was studied for 7 years under the arid climate of southwestern Arizona. Trees on macrophylla (Alemow) (C. macrophylla Wester) were the most precocious and produced the highest yields 4 years after planting. Seven-year cumulative yields of trees on Carrizo citrange [C. sinensis (L.) Osbeck × Poncirus trifoliata (L.) Raf.], Yuma citrange (P. trifoliata × C. sinensis), Volkamer lemon (C. limon Burm f.), rough lemon (C. jambhiri Lush), Taiwanica (C. taiwanica), and macrophylla were similar and higher than those on Savage citrange (P. trifofiata × C. sinensis), Batangas mandarin (C. reticulata Blanco), Ichang pummelo (C. ichangensis hyb.), and Palestine sweet lime (C. limettoides Tan.). Trees on Carrizo citrange had relatively large tree canopies and larger fruit, and fruit from trees on Volkamer lemon and rough lemon was lower in total soluble solids concentration (TSS) and total acids (TA) than fruit from trees on other rootstocks. Fruit from trees on Savage citrange was smallest but had the highest TSS. Considering yield, growth, and/or various quality factors, Volkamer lemon, rough lemon, Yuma citrange, and particularly Carrizo citrange, are suitable for `Orlando' tangelo in the arid regions of the southwestern United States. Trees on macrophylla, Savage citrange, and Ichang pummelo had small canopies and were least productive. `Orlando' tangelo trees on Savage citrange and Ichang pummelo rootstocks, however, might be good choices at a spacing closer than 7 × 7 m because of their high fruit TSS and fruit size, respectively. Trees on Palestine sweet lime declined and had low yields, and those on Batangas mandarin had low yields and poor fruit quality. These rootstocks are not recommended for `Orlando' tangelo under conditions similar to those of this experiment.
Diagnostic Evidence of Damage on Pecan Shells by Stink Bugs and Coreid Bugs
Authors: Yates I.E. , Tedders W.L. , Sparks Darrell
Published: January 2019

Feeding activity by several species of phytophagous stink bugs and coreid bugs (Pentatomidae and Coreidae) on the fruits of pecan [Carya illinoensis (Wangenh.) C. Koch] causes severe economic losses in nut yield and kernel quality. Verification of late-season damage by these insects to pecan nuts has been possible only after examination of the condition of the kernel. Staining nuts with a red fluorescent tracing dye resulted in a differential contrast between the surface of the shell and sites of hemipteran punctures. This technique can be used with the aid of a dissecting microscope to identify hemipteran bug damage by examining the exterior of the shell. Stylet sheaths connecting the packing material on the shell interior to the seedcoat of the kernel have been identified and can be used as confirmatory evidence of hemipteran attack.
Lowbush Blueberry Quality Changes in Response to Mechanical Damage and Storage Temperature
Authors: Sanford K.A. , Lidster P.D. , McRae K.B. , Jackson E.D. , Lawrence R.A. , Stark R. , Prange R.K.
Published: January 2019

Postharvest response of wild lowbush blueberry (Vaccinium angustifolium Ait. and V. myrtilloides Michx.) to mechanical damage and storage temperature was studied during 2 years. Fruit weight loss and the incidence of shriveled or split berries were major components that contributed to the loss of marketable yield resulting from mechanical damage and storage temperature. Decay of berries resulted in only 1% to 2% of the total marketable fruit loss. In general, the major quality attributes (firmness, microbial growth, hue, bloom, split, and unblemished berries) deteriorated with increasing damage levels and increasing storage temperature without significant interaction. Temperature had consistent effects in both years on moisture content, soluble solids concentration, titratable acids, weight loss, shriveled and decayed berries, Hunter L values, and anthocyanin leakage, while damage level had inconsistent or no significant effect.
Detection of Mechanical Injury and Physiological Breakdown of Cucumbers Using Delayed Light Emission
Authors: Abbott Judith A. , Miller A. Raymond , Campbell T. Austin
Published: January 2019

Mechanical stress received by pickling cucumbers (Cucumis sativus L.) during harvest can cause physiological degeneration of the placental tissues, rendering the cucumbers unsuitable for use in some pickled products. Cucumbers were subjected to controlled stresses by dropping and rolling under weights to induce such degeneration. Following storage at various temperatures for O, 24, and 48 hours, refreshed delayed light emission from chlorophyll (RDLE) was measured and transmission electron micrographs of chloroplasts were made. Mechanical stress rapidly suppressed RDLE and induced accumulation of starch granules within the chloroplasts. Rolling usually had a greater effect on RDLE than did dropping. After 48 hours, RDLE suppression persisted; starch granules were no longer evident in chloroplasts from mechanically stressed fruit, but very electron-dense inclusions had developed in the chloroplasts. Storage temperatures affected RDLE levels but had minimal interaction with stress responses. Cucumber lots subjected to excessive mechanical stress likely could be detected using RDLE measurement.
Identification of Bacteria Infecting Seedlings of Mung Bean Used in Rooting Bioassays
Authors: Tripepi R.R. , George M.W.
Published: January 2019

Seeds of `Berken' mung bean [Vigna radiata (L.) R. Wilcz.] were surface-sterilized with NaOCl and then either aerated 24 hours before sowing (routine procedure), planted immediately after the NaOCl treatment, or treated with hot cupric acetate and antibiotics before planting. Nine- or 10-day-old seedlings were used in rooting bioassays. Up to 10% of the seedlings and 17% of the cuttings had collapsed upper stems or wilted leaves. None of the seed treatments completely eliminated the pathogen, but the combination of hot cupric acetate plus antibiotics reduced the quantity of diseased cuttings to 3.3%. A white and two yellow-pigmented (Y1 and Y2) bacteria were isolated from diseased cuttings and used in subsequent pathogenicity tests. The Y2 strain was nonpathogenic. Stems of plants inoculated with the white strain turned brown and collapsed 2 days after inoculation, whereas leaves of plants inoculated with the Y1 strain wilted after 7 days. Electron microscopy, fatty acid analysis, and standard biochemical and physiological tests were used to identify the white strain as Pseudomonas syringae pv. syringae van Hall and the Y1 strain as Curtobacterium flaccumfaciens ssp. flaccumfaciens (Hedges) Collins and Jones. These results emphasize that seeds of mung bean should be checked for seedborne pathogens to avoid experimental artifacts.
Relationships among Indices for the End of Bud Dormancy in Apple Cultivars and Related Malus Species under Cold Winter Conditions
Authors: Hauagge Roberto , Cummins James N.
Published: January 2019

Relationships among estimates for the length of bud dormancy over a wide range of cultivars of Malus × domestics Borkh. and related Malus spp. are reported. Flower bud dormancy state was estimated after fitting quadratic models for the number of days for 50% terminal budbreak (D50), bud development stage (BDS), and percent terminal budbreak (BB) after 21 days of forcing as a function of chilling unit (CU) accumulation. Cultivar, linear, and quadratic components of regression, as well as all interactions, were significant for D50, BDS, and BB when regressed against CU accumulation. Consequently, cultivars differ not only as to when changes in “dormancy intensity take place, but also in the patterns and rates at which these changes proceed. The number of CU needed to reach arbitrary stages of each characteristic at the end of dormancy was calculated and compared for all genotypes. Rates of CU accumulation until BB, BDS, and D50 reached 50%, 1.5 and 15 days, respectively, were well-correlated. These CU values were considered the end of bud dormancy or genotype chilling requirement (CR). Estimations of D50 were less variable and less subjective, and a wider range of data points could be used in the analysis. In addition, values for D50 can indicate the growth potential of buds when other indices do not show changes. A few sampling times during the dormant season may give a preliminary idea about the CR of a given genotype.
Quality and Storage of `Granny Smith' and `Greenspur' Apples on Seedling, M.26, and MM.111 Rootstock
Authors: Drake Stephen R. , Larsen Fenton E. , Higgins S.S.
Published: January 2019

Influences of rootstock on the quality of `Granny Smith' and `Greenspur' apples (Malus domestica Borkh.) were evaluated over an extended harvest period and after cold storage. Apples from trees on M.26 rootstock had the higher firmness, soluble solids concentration (SSC), and Ca content, but poorer external color (red blush) and a higher percentage of solar injury than fruit from trees on seedling or MM.111 rootstock. External greenness was best on apples from MM.111 rootstock. `Granny Smith' apples had higher firmness, soluble solids, acids, and carbohydrate contents, and less scald but poorer external greenness than `Green spur' apples. `Granny Smith' or `Greenspur' apples from M.26 rootstock appeared to mature earlier than those on MM.111.
Isozymic Identification of Zygotic Seedlings in Swingle Citrumelo Citrus paradisi × Poncirus trifoliata Nursery and Field Populations
Authors: Anderson Catalina M. , Castle William S. , Moore Gloria A.
Published: January 2019

Isozyme analysis was the basis for determining the frequency of occurrence and the characteristics of zygotic plants in Swingle citrumelo seedling populations from various sources of open-pollinated seeds, in a commercial nursery of Swingle citrumelo before and after roguing, and in commercial orchards and rootstock trials where this rootstock was used. Most zygotic seedlings identified by isozyme analysis could be distinguished by careful examination of morphological characteristics. Frequencies of zygotic seedlings varied among seedling populations, but were in the range (≈5% to 10%) found in previous studies. Roguing based primarily on size and growth habit of seedlings was effective in removing some, but not all, zygotic seedlings. Most of the remaining zygotic plants in the rogued population were found among the smaller seedlings. Trees budded on zygotic rootstock seedlings were found in two of the three groves studied, and in some instances an apparent incompatibility was developing in young trees.
Peach Fruit Quality Is Affected by Shade during Final Swell of Fruit Growth
Authors: Marini Richard P. , Sowers Donald , Marini Michele Choma
Published: January 2019

Girdled or nongirdled `Biscoe' peach (Prunus persica [L.] Batsch) secondary scaffold branches were covered with shade fabric to provide a range of photosynthetic photon flux densities (PPFD) from 44 to 20 days before harvest (DBH), from 20 to 0 DBH or 44 to 0 DBH. Fruit quality was affected differently by the various periods of shade during the final swell of fruit development. Shading 40 to 20 DBH did not affect fruit weight or quality, whereas shading 44 to 0 DBH had the greatest effect on fruit weight and quality. Fruit quality was generally similar on branches exposed to 100% and 45% incident PPFD (IPPFD). Fruit on” girdled branches generally responded to shade more than fruit on nongirdled branches. Fruit weight was positively related to percent IPPFD for girdfed but not nongirdled branches shaded 20 to 0 DBH and 44 to DBH. On nongirdled branches, fruit exposed to 45% IPPFD for 44 to 0 DBH had 14% less red color and 21% lower soluble solids content (SSC) than nonshaded fruit. Harvest was delayed >10 days and preharvest fruit drop was increased by shading to <23% IPPFD. Shading branches for 20 to 0 or 44 to 0 DBH altered the relationship between flesh firmness and ground color: Firmness declined as ground color changed from green to yellow for fruit shaded 44 to 20 DBH, but firmness declined with little change in ground color for fruit shaded 20 to 0 or 44 to 0 DBH. Girdling results indicated that fruit weight and SSC partially depended on photosynthate from nonshaded portions of the canopy, whereas fruit redness, days from bloom to harvest, and ground color depended on PPFD in the vicinity of the fruit.
Natural Season-long and Diurnal Temperature Effects on Lettuce Seed Production and Quality
Authors: Steiner J.J. , Opoku-Boateng K.
Published: January 2019

We investigated the effects of variation in ambient air temperature on seed production in the field during the reproductive development phase of `Salinas' head-type lettuce (Luctuca sativa L.) in the central San Joaquin Valley of California where daytime maxima may exceed 38C for many consecutive days during reproduction. Florets were tagged daily for 41 days and harvested seeds were sampled to determine temperature-sensitive periods during seed development. The number of seeds per inflorescence (NOS), seed mass (SM), and seedling root length (SRL) were reduced and percentage germination (GERM) increased with increasing minimum (LT) and maximum (HT) temperatures. Daily HT > 35C greatly reduced NOS. Increasing LT reduced SM and SRL, but to a lesser extent than NOS (r2 = 0.23 and 0.40; P = 0.01 and 0.001, respectively). The advantage of increasing HT on GERM (r2 = 0.20; P = 0.01) was overshadowed by the severe reduction in NOS and the vigor components SM and SRL. The periods of greatest sensitivity to high air temperature for NOS, SM, GERM, and SRL were - 1 to +1, - 4, +1, and - 4 to - 3 days from anthesis, respectively. The hours of peak sensitivity for these variables occurred during the same days at - 36, - 101, + 15, and - 83 hours from anthesis, respectively. Using Box-Jenkins time series analysis, diurnal periodicity in temperature sensitivity for the four variables was determined.
Short-term Effect of Uniconazole on the Water Relations and Growth of Ligustrum
Authors: Steinberg Susan L. , Zajicek Jayne M. , McFarland Marshall J.
Published: January 2019

Growth of potted Ligustrum was controlled by uniconazole at 3.0 mg a.i./pot. Uniconazole inhibited growth by inducing shorter internodes with smaller diameter and by reducing secondary branching and new leaf production. As a result, the total leaf area of the treated plants was 6396 less than the control plants. The chlorophyll content of recently expanded leaves was 27% lower in treated than in control plants, even though there were no visual differences in leaf color. Leaves of treated plants also had a 28% higher stomatal density than the control. The liquid flow conductance of Ligustrum was 3.7 × 10-14 m·s-1·Pa-1 and was similar for plants in both treatments. Differences in daily water, use between the two treatments began to appear at the same time as differences in growth. Total water use of treated plants was 13% less than that of the control. When daily water use was normalized on a-leaf-area basis, water use between treatments was similar, suggesting that differences in total water use were primarily due to differences in leaf area. For plants in both treatments, peak sap flow rates in the main trunk ranged between 60 and 100 g·h-1·m-2. Leaf conductance, transpiration rates, and water potential were also similar for treated and control plants. Chemical name used: (E)-1-(4-chlorophenyll) -4,4, -dimethyl-2-(l,2,4-triazo1-l-y1)-l-penten-3-ol (uniconazole).
Adaptive Responses of Walnut Pollen Germination to Temperature during Pollen Development
Authors: Polito Vito S. , Weinbaum Steven A. , Muraoka Tom T.
Published: January 2019

Experiments were conducted to determine if differential responses of walnut pollen germination to temperature, previously observed to occur among genotypes, were genetically fixed or expressions of phenotypic plasticity representing adaptive responses to temperatures experienced during pollen development. Individual branches of a single walnut (Juglans regia L. cv. Serr) tree were warmed above ambient conditions during the final stages of pollen differentiation by directing a stream of moist, heated air into polyethylene enclosures, each containing an individual branch unit. Pollen was collected at staminate anthesis and incubated in germination medium on a temperature gradient apparatus. Model curves fitted to the in vitro pollen germination data were used to determine optimum germination temperatures. We found adaptive responses of pollen germination to temperatures experienced during pollen development. The optimum temperature for in vitro germination for pollen from branches maintained under ambient conditions was lower than that of pollen from branches with elevated temperature, and optimum germination temperature increased as a log function of integrated daily temperature (degree-days) experienced during pollen development.
Paper Birch and European White Birch Vary in Growth and Resistance to Bronze Birch Borer
Authors: Miller Raymond O. , Bloese Paul D. , Hanover James W. , Haack Robert A.
Published: January 2019

A test of Michigan half-sib progeny of paper birch (Betula papyrifera Marsh.) and European white birch (B. pendula Roth.) was conducted in Michigan to examine species variation in growth, bark color, and resistance to bronze birch borer (Agrilus anxius Gory). Paper birch was superior to European white birch in height and borer resistance at age 12 years from seed. Families of paper birch were identified that grew exceptionally well, had developed white bark within 6 years, and exhibited borer resistance. The magnitude of additive genetic variance and narrow-sense family heritability estimates for paper birch indicated that sufficient genetic variation and inheritance exist to support selection and breeding for height. Paper birch may be an acceptable substitute for European white birch as a landscape species in northeastern North America.
Increased CO2 and Light Promote in Vitro Shoot Growth and Development of Theobroma cacao
Authors: Figueira Antonio , Whipkey Anna , Janick Jules
Published: January 2019

Axillary shoots of cacao (Theobroma cacao L.), induced in vitro with cytokinins (BA or TDZ), elongated and produced leaves only in the presence of cotyledons and/or roots. Detached axillary shoots, which do not grow in `vitro under conventional tissue culture protocols, rooted with auxin and developed normally in vivo. Detached axillary shoots from cotyledonary nodes and single-node cuttings from mature plants were induced to elongate and produce normal leaves in the presence of 20,000 ppm CO2 and a photosynthetic photon flux density (PPFD) of 150 to 200 μmol·s-1·m-2. Subculture nodal cuttings continued to elongate and produce leaves under elevated CO2 and light levels, and some formed roots. Subculture of microcuttings under CO2 enrichment could be the basis for a rapid system of micropropagation for cacao. Chemical names used: N -(phenylmethyl) -1 H -purin-6-amine (BA); 1 H -indole-3-butyric `acid (IBA); α -naphthaleneacetic acid (NAA); thidiazuron (TDZ).
Propagation Medium Moisture Level Influences Adventitious Rooting of Woody Stem Cuttings
Authors: Rein William H. , Wright Robert D. , Seiler John R.
Published: January 2019

Stem cuttings of Blue Rug juniper (Juniperus horizontalis Moench `Wiltonii'), `Hino-Crimson' azalea [Rhododendron (Lindl.) P1anch `Hino-Crimson'], and `Helleri' holly (Ilex crenata Thunb. `Helleri') were propagated in 1 peat: 1 perlite (v/v) at one of five moisture levels based on medium dry weight (125%, 250%, 375%, 500%, or 625%). Cutting survival and percentage of rooted cuttings were highest at the highest medium moisture level in all three species. Incidence of cutting basal rot was not directly related to medium moisture level, but more to the growth stage of the stock plant. Midday xylem water potential (ψ) of cuttings for each species was highest in the wettest propagation medium and lowest in the driest medium. During propagation, stem cutting ψ below - 2.0 MPa occurred even in the wettest medium tested, and frequently reached - 4.0 MPa in cuttings in the driest treatment (125%). Basal water uptake by cuttings was highest in the wettest medium moisture level. Water uptake was highest during the first few days after insertion, and thereafter decreased until root emergence.