Glynn Percival

University of Reading · Plant Science

Management of fungal diseases within urban landscapes relies heavily on repeat fungicide sprays. Environmental concerns have led to a need to eliminate or reduce fungicide use. Foliar sprays of calcium- (Ca) and silicon- (Si) based fertilisers have been shown to reduce symptom severity of several fungal pathogens. The aim of our research was to eva...

Pear rust is a foliar pathogen of ornamental and fruiting pear trees. Unmanaged, yield and aesthetic losses can be severe. Over-reliance on synthetic fungicides means novel means of pathogen management are required. Field trials were conducted using pear (Pyrus cv. Conference) to assess the efficacy of electrolysed oxidizing water (EO water) as a r...

Unmanaged, foliar pathogens of urban trees can be detrimental to tree health and aesthetics. Overreliance on synthetic fungicides increasingly means alternative means of pathogen management are now required. The purpose of these studies was to investigate the efficacy of 3 commercially available agents, harpin protein, salicylic acid derivative, an...

Unmanaged, foliar diseases of nursery stock can be detrimental to woody plant biology and aesthetics. Build-up of disease resistance due to an over-reliance on synthetic fungicides means alternative disease management strategies are now recommended. The purpose of these studies was to investigate the effectiveness of three resistance inducers, harp...

Apple and pear scab are foliar diseases of ornamental and fruiting apple and pear trees. Unmanaged, yield and aesthetic losses can be severe. Overreliance on synthetic fungicides means novel means of disease management are required. Field trials were conducted using apple (Malus cv. Crown Gold) and pear (Pyrus communis ‘Williams Bon Chrétien’) to a...

Bleeding canker of horse chestnut trees is a bacterial disease, caused by the bacterium Pseudomonas syringae pv. aesculi, estimated to be present in ~ 50% of UK horse chestnut trees. Currently, the disease has no cure and tree removal can be a common method of reducing inoculum and preventing spread. One potential method of control could be achieve...

Key message Cultivars of Acer platanoides, A. pseudoplatanus and A. campestre show significant seasonal drought tolerance variation, identified by in vitro desiccation a whole-tree drought and water potential at turgor-loss-point. Abstract Drought is one of the most common and significant disorders affecting tree establishment and growth, in the u...

Glyphosate is a commonly used systemic herbicide in urban landscapes. Incidental spray drift and/or ground water contamination potentially represents an under-estimated problem that can detrimentally impact on the biology of trees. There are few studies that have investigated differences in tolerance of urban trees to glyphosate-induced oxidative s...

Two separate trials during 2010 and 2011 were conducted using field grown white flowering horse chestnut trees (Aesculus hippocastanum L.) to asssess the insecticidal efficacy of three systemic inducing agents (SIR), namely (Messanger (active substance (a.s.) Harpin protein), Phoenix (a.s. Potassium phosphite) and Rigel (a.s. Salicylic acid derivat...

The aim of this study was to determine the influence of trunk applied insect barrier glue bands and liquid glue on reducing horse chestnut leaf miner (HCLM) severity on the white flowering horse chestnut tree Aesculus hippocastanum L. Treatments were applied to coincide with the emergence of the first adult moth generation. All glue treatments (ban...

High mortality rates result from transplanting bare-rooted plants into urban landscapes where unsuitable soil conditions, such as low fertility and poor structure, often exist. Coupled with little aftercare, these losses can cause high economic losses to the industry. Previous studies have shown lowered transplant stress and higher survival rates t...

Accidental (strimmer, mower) or malicious girdling of ornamental trees is a frequent and underestimated problem in urban landscapes. No guidelines exist for landscape managers on the likelihood of fatal damage according to time of girdle, i.e., season (spring, winter) and extent of girdling. This report investigated the effect of stem girdling (0%,...

Widespread flooding across the UK has become an annual problem within the UK. Consequently, trees are subject to prolonged periods of time (4–6 months) when their root systems are submerged under water. This review aims to highlight the detrimental impacts of prolonged flooding on tree biology, and discuss remedial measures and aftercare management...

These proceedings from the 2014 Trees People and the Built Environment II (TPBEII) conference, a major international urban tree research event, mark a milestone in the development of our urban forests and green infrastructure. Some of the key themes covered in the publication include the environmental, economic and social benefits of urban trees an...

Developments in water-retaining polymer (WRP) technology have led to the use of polymer crystals or granules that are incorporated into the soil medium as an amendment rather than a root dip and/or by addition of root-enhancing compounds such as sugar and mycorrhiza into the gel. The influence of three commercially available WRPs applied as a root...

Field trials were conducted using 4-year-old horse chestnut (Aesculus hippocastanum L.) to assess the efficacy of potassium and silicon phosphite as plant protection agents against the bacterial pathogen Pseudomonas syringae pv. aesculi (Pae) the causal agent of Pseudomonas bleeding canker of horse chestnut. Phosphites were applied preventatively,...

The white flowering horse chestnut tree (Aesculus hippocastanum L) was first introduced to the UK ca. 500 years ago. Over the past eight years however, this tree has suffered from severe attack by a mining insect pest known as the horse chestnut leaf miner (HCLM; Cameraria ohridella) and, concomitantly a gram negative bacterium (Pseudomonas syringa...

High mortality rates following planting out of ornamental trees into urban landscapes is a common phenomenon within the UK. Previous research has shown that the quantity of reserve carbohydrates in root tissue is crucial for successful survival following transplanting from the nursery into field conditions. Enhancing the root carbohydrate status of...

Potassium phosphite is a widely used plant protection agent. However, a suite of phosphite formulations with alternative cation attachments (calcium, copper, silicon, zinc) are commercially available. The plant protective properties of these formulations have received little attention. This study evaluated five phosphite formulations for plant prot...

Rural trees are trees not used for timber purposes or located within urban landscapes such as towns and cities. Rural tree use and function varies between developed, developing and under-developed countries. Conservation and ecology are the main factors driving rural tree planting in developed countries whereas food production, animal protection an...

Glasshouse trials were conducted using tobacco (Nicotiana benthamiana) to assess the efficacy of five plant defence activators (PDAs), namely harpin protein, potassium phosphite, salicylic acid analogue, silicon phosphite and a plant hormone–vitamin complex against the bacterial pathogen Pseudomonas syringae pv. aesculi (Pae), the causal agent of P...

Urban environments present an array of environmental conditions detrimental to the biology of trees. Two major problems include deicing salts, a common soil pollutant, and drought. One potential option for managing these environmental disorders may be through the application of commercially available biostimulants, as these products are reported to...

Mulching as a means of controlling Phytophthora root rot pathogens has become recognised as a potential cultural management system within the arboricultural, nursery and landscape industry. The influence of a pure mulch, i.e., mulch derived solely from one tree species, on reducing Phytophthora root rot severity has received little study. The purpo...

The influence of six commercially available fungicides incorporated into a water-retaining polymer and applied to the root system of horsechestnut (Aesculus hippocastanum L.) as a dip at the time of planting was conducted. Potential increases in resistance against the foliar pathogen Guignardia leaf blotch (Guignardia aesculi) was then monitored ov...

Two separate trials during 2007 and 2008 were conducted using containerized white flowering horse chestnut trees (Aesculus hippocastanum L.) to assess the efficacy of a range of insecticides applied at three different times during a growing season against the insect pest, horse chestnut leaf miner (Cameraria ohridella Deschka and Dimic; HCLM). Inse...

Biostimulants are classified as materials that are neither a fertilizer nor a pesticide, but when applied to a plant will enhance their health, growth, and protection. Manufacturers claim biostimulants have underexploited potential in providing protectant properties to plants against pathogen attack. This study evaluated the efficacy of seven comme...

Biostimulants are classified as materials that are neither a fertilizer nor a pesticide, but when applied to a plant will enhance their health, growth, and protection. Manufacturers claim biostimulants have underexploited potential in providing protectant properties to plants against pathogen attack. This study evaluated the efficacy of seven comme...

The aim of this study was to evaluate the impact of horse chestnut leaf miner (Cameraria ohridella Deschka and Dimic; HCLM) on whole-tree energy loss, growth and reproduction on mature horse chestnut trees Aesculus hippocastanum L. Electron transport (ETo) flux per cross section (CS) of photosystem II (ETo/CS) was measured on HCLM infested and inse...

Systemic acquired resistance (SAR) is the phenomenon whereby a plant's own defense mecha- nisms are induced by prior treatment with either a bio- logical or chemical agent. The concept of SAR has been widely recognized and studied for the past 100 years in relation to increasing resistance to fungal, bacterial, and viral pathogens of economically i...

The best time to plant a tree was twenty years ago. The second best time is now.' Anonymous Abstract Mortality of landscape trees regularly reaches 30% in the first year after planting. This review aims to highlight the fundamental factors and procedures critical to tree establishment. If these are fully considered and acted upon, significant reduc...

Honey fungus (Armillaria mellea) is an important pathogen that can cause severe damage to infected trees and other plants. In this study we investigated the effect of air-spading and/or inoculation with a bio-control fungus as controls for honey fungus. Air-spading uses compressed air to de-compact soil while causing minimal disturbance or damage t...

The aim of this study was to determine the usefulness of trunk and scaffold limb sprays of the insect growth regulator diflubenzuron on reducing horse chestnut leaf miner (HCLM) severity on the white flowering horse chestnut tree Aesculus hippocastanum L. One bark and scaffold limb spray applied to coincide with the emergence of the first adult mot...

The ability of penconazole, a triazole fungicide derivative, to protect against and ameliorate heat stress was studied in evergreen oak (Quercus ilex) and Scots pine (Pinus sylvestris). Under laboratory conditions, heat damage to the leaf photosynthetic system based on the stability of the chlorophyll a/b light-harvesting complex within photosystem...

The purpose of this study was to investigate the use of potassium phosphite (Pi) alone and in combination with a reduced dose of synthetic fungicide (myclobutanil) to control pear scab (Venturia pirina) under field conditions. Irrespective of Pi and myclobutanil concentration, no leaf or fruit phytotoxic effects were observed throughout the 2006 an...

A detached leaf bioassay was used to evaluate several systemic inducing resistance agents, a range of biostimulant products and a conventional triazole fungicide (myclobutanil) on apple scab (Venturia inaequalis) development under laboratory conditions. None of the biostimulant products (seaweed extract, betaine, molasses, humic acid, yucca extract...

The aim of this study was to determine the influence of a range of commercially available fertilisers on tree responses following salt (sodium chloride) damage to foliar tissue of containerized evergreen oak (Quercus ilex) and Scots pine (Pinus sylvestris). Evergreen oak proved to be more salt tolerant than Scots pine. Tree responses to fertilisati...

Mulching as a means of reducing soil moisture stress, suppressing weed growth and improving soil fertility is widely recognised throughout the arboricultural, nursery and landscape industry. The influence of a pure mulch, i.e. mulch derived solely from one tree species, has received little study. The purpose of this research was to evaluate pure mu...

A goal of pathogen management in the arboriculture industry should be to eliminate or reduce the amount of active ingredients of synthetic fungicides used within a growing season. The aim of this research paper was to evaluate a nonfungicidal pathogen management system by investigating the hypothesis that replacing an apple scab fungicide spray pro...

Two field trials were conducted using established apple (Malus cv. Golden Delicious) and pear (Pyrus communis ‘Williams’ Bon Chrétien') to assess the efficacy of three commercially available systemic inducing resistance (SIR) products, Messenger (a.i. Harpin protein), Phoenix (a.i. Potassium phosphite) and Rigel (a.i. Salicylic acid derivative) app...

A detached leaf bioassay was used to determine the influence of several film forming polymers and a conventional triazole fungicide on apple scab (Venturia inaequalis (Cooke) G. Wint.) development under laboratory in vitro conditions, supported by two field trials using established apple cv. Golden Delicious to further assess the efficacy of foliar...

We determined the influence of the triazole derivatives paclobutrazol, penconazole, epixiconazole, propiconazole and myclobutanil on the drought tolerance and post drought recovery of container-grown horse chestnut (Aesculus hippocastanum L.) saplings. Myclobutanil neither conferred drought resistance, as assessed by its effects on a number of phys...

A 2 year field trial was conducted using established English oak (Quercus robur L.) to assess the efficacy of four commercially available systemic-inducing resistance (SIR) compounds (salicylic acid, potassium phosphite, harpin protein, be- taine) applied as a single therapeutic spray treatment against the foliar pathogen oak powdery mildew (Micros...

A three year field trial was conducted using established apple (Malus cv. Crown Gold) and horse chestnut (Aesculus hippocastanum L.) to assess the efficacy of paclobutrazol (PBZ) root drenches against the foliar pathogens apple scab (Venturia inaequalis (Cooke) G. Wint.,) and Guignardia leaf blotch (Guignardia aesculi (Peck) VB Stewart). In the cas...

Greater variability in weather patterns and later spring frosts equate to poor winter hardiness, premature spring budbreak, and greater susceptibility to low-temperature damage and concomitant deicing salt application. A field trial was undertaken to determine the influence of a range of commercially available calcium fertilizers applied as foliar...

The chlorophyll content (or SPAD meter) is a simple, portable diagnostic tool that measures the greenness or relative chlorophyll content of leaves. Compared with the traditional destructive methods of chlorophyll extraction, the use of this equipment saves time, space, and resources. The objective of this study was to establish a correlation betwe...

Root functionUrban soilForms of damage to treesManaging root growthShrinkable soilsAvoiding conflicts between urban trees and peopleReferences

The aims of this study were to determine the influence of nitrogen (N) fertilizers on tree tolerance under prolonged waterlogging conditions and investigate the effect of N fertilization on aiding tree recovery from waterlogging damage using containerized English oak (waterlogging-intermediate) and European beech (waterlogging-sensitive) as test sp...

The influence of carbohydrates and slow release nitrogen fertilisers in combination with a water-retaining polymer applied as a dip to the root system of two transplant-sensitive tree species, silver birch (Betula pendula Roth.) and European beech (Fagus sylvatica L.) under field conditions was investigated. The efficacy of the treatment on growth...

The influence of paclobutrazol (PBZ) applied as a foliar spray and root drench on drought tolerance and recovery from drought, of containerized English and evergreen oak was investigated. PBZ treatment induced a suite of physiological adaptations that would allow both species to tolerate drought; more specifically, increased total leaf content of c...

A field trial was undertaken to determine the influence of four commercially available film-forming polymers (Bond (alkyl phenyl hydroxyl polyoxyethylene), Newman Crop Spray 11E™ (paraffinic oil), Nu-Film P (poly-1-p men- thene), and Spray Gard (di-1-p menthene)) on reducing salt spray injury on two woody species, evergreen oak (Quercus ilex L.) an...

Two outdoor experiments were conducted using containerized trees of the species holly (Ilex aquifolium L.) and English oak (Quercus robur L.) to determine the effectiveness and feasibility of sucrose to improve tolerance to and recovery from deicing salt (sodium chloride (NaCl)) damage. In experiment one, sucrose plus a water-only control was appli...

The influence of five commercially available biostimulant products (Trade names; Generate, Resistim, Fulcrum CRV, Bioplex, Maxicrop) in combination with a water-retaining polymer applied to the root system of silver birch (Betula pendula Roth.) and rowan (Sorbus aucuparia L.) during the winter period under field conditions was investigated. The sho...

The Fraxinus genus consists of ca. 65 deciduous, rarely evergreen trees found mainly throughout Europe, Asia and North America. Fraxinus species possess the aesthetic characteristics desired of urban trees (autumn colour, attractive bark and flowers); however, no scientifically based tolerance ranking exists for many genotypes within this genera. A...

The effects of four commercially available film-forming polymers (Bond, Designer, Spray Gard, Nu-Film-P) on disease severity of powdery mildew (Microsphaera alphitoides Griffon and Maubl.) on English oak (Quercus robur L.) and Guignardia leaf blotch (Guignardia aesculi (Peck) Stewart) on horsechestnut (Aesculus hippocastanum L.) were examined in a...

A 3-year field trial was conducted using established apple cv. Crown Gold and English oak (Quercus robur L.) to assess the efficacy of eight fungicides applied via microcapsule trunk injection against the foliar pathogens apple scab (Venturia inaequalis) and powdery mildew (Phyllactinia sp). In both apple cv. Crown Gold and English oak, the fungici...

Aims of this investigation were to determine whether chlorophyll fluorescence values obtained from excised leaves of woody perennials subjected to salinity stress under laboratory conditions provided a measurable indicator of whole plant salinity tolerance. Laboratory tests consisted of measurements of the ratio of variable to maximal chlorophyll f...

During their lifetime, urban trees are susceptible to a range of environmental and chemical stresses that can result in tree decline. Chlorophyll fluorescence has been used as a nondestructive and noninvasive means of quantifying damage to the leaf photosynthetic system of deciduous and evergreen trees. Aims of this investigation were to determine...

Two field trials undertaken in 1999 and 2003 investigated the influence of a range of sugars applied as a root drench at 25, 50, and 70 g/L (3.4, 6.8, and 10.3 oz/gal) of water on root and shoot growth, chlorophyll fluorescence, photosynthetic rates, and leaf carotenoid and chlorophyll concentrations of birch (Betula pendula Roth.). Irrespective of...

Two field trials were undertaken to determine the influence of fall fertilization using two commercially available, calcium-based fertilizers (calcium nitrate, calcium nitrate borate) and a high-nitrogen fertilizer (N:P:K = 24:7:7), at a range of concentrations, on the freezing and salinity tolerance of two urban tree species, evergreen oak (Quercu...

Four established mature tree species (Aesculus hippocastanum L., Betula pendula Roth., Primus avium L. and Quercus rohur L.) commonly planted in UK urban landscapes were subjected to soil injections of the carbohydrate sucrose at 25, 50 and 70g per litre of water. Fine root dry weight was recorded at month 5 following soil injections. Soil injectio...

The influence of two commercially available auxin products (IBA talc, IBA:NAA solution) in combination with a water-retaining polymer applied to the root system of two transplant-sensitive tree species, silver birch (Betula pendula Roth.) and beech (Fagus sylvatica L.) under field conditions was investigated. The efficacy of the auxins on growth wa...

The influence of sugar (sucrose) applied as a root drench at 25, 50, or 70 g (0.9, 1.8, or 2.7 oz) per liter of water on root and shoot vigor, leaf chlorophyll fluorescence, photosynthetic rates, and chlorophyll content in silver birch (Betula pendula), red oak (Quercus rubra), cherry, (Prunus avium), and rowan, (Sorbus aucuparia) was investigated....

High mortality rates of bare-root stock can occasionally occur post-planting due to poor plant vitality at the time of planting. Consequently, physiological tests of plant vitality, such as stem electrolyte leakage, root growth potential (RGP), and chlorophyll fluorescence, are valuable because of their ability to identify low-vigor or damaged plan...

Four commercially available, biostimulants sold under the trade names ‘Generate’, ‘Crop Set’, ‘Fulcrum’ and ‘Redicrop 2000’ were applied either as a root drench or foliar spray to three transplant-sensitive tree species, red oak(Quercus rubra), birch(Betula pendula) and beech (Fagus sylvatica) post transplanting. The short and long-term efficacy of...

The effect of increasing salinity on a range of chlorophyll fluorescence parameters in foliar tissue of 30 Acer genotypes was examined. The magnitude of the fluorescence responses differed among genotypes ranging from minor effects to substantial leaf tissue damage. Interpretation of the fluorescence expressions provided an insight into mechanisms...

The purpose of this research was to determine whether chlorophyll fluorescence values obtained from excised leaves of urban trees subjected to freezing under laboratory conditions provided a measurable indicator of whole-tree freezing tolerance under glasshouse conditions. Laboratory tests consisted of measurements of the ratio of variable to maxim...

The effect of powdery mildew development on photosynthesis, chlorophyll fluorescence, leaf chlorophyll and carotenoid concentrations on three woody plants frequently planted in urban environments was studied. Rates of photosynthetic CO fixation were rapidly reduced in two of the three genotypes tested prior to visible signs of infection. Effects on...

The purpose of this research was to determine whether chlorophyll fluorescence values obtained from excised leaves of woody plants subjected to dehydration in vitro provided a measurable indicator of whole-plant performance following drought in situ and to gain a greater understanding of alterations in leaf photosynthetic properties between species...

Seven tree species (Acer campestre, Betula pendula, Ilex aquifolium, Jugulans regia, Quercus ilex, Prunus avium, and Sorbus aucuparia) commonly planted into urban landscapes throughout the UK were subjected to foliar applied salt (NaCl). Chlorophyll fluorescence, photosynthetic rates, leaf chlorophyll content and growth were used to assess short an...

Increases in resistance of aerial tubers (cultivars Désirée, Epicure and King Edward) against nine pathogenic potato fungi were determined in vitro using freeze-dried powder derived from subterranean and aerial tubers as a culture medium, and in vivo by inoculating both tuber types with the storage pathogens Fusarium sulphureum,F. solani var. coeru...

Increases in resistance to Fusarium sulphureum and Fusartium solani var. coeruleum were determined in seed tubers of cultivars Desiree, Pentland Hawk and Kerr's Pink with light-enhanced glycoalkaloids. Glycoalkaloid concentration in the tubers ranged from 78.0 to 885.9 mg kg−1 fresh weight. Exposure of tubers to light prior to inoculation decreased...

The effect of increasing salinity and freezing stress singly and in combination on a range of chlorophyll fluorescence parameters in foliar tissue of six Crataegus genotypes was examined. In general, increased stress reduced fluorescence values and absorption, trapping and electron transport energy fluxes per leaf reaction center and cross section,...

The influence of 2 weeks and 3 months of dark storage upon light-induced chlorogenic acid accumulation within tuber tissue of four potato cultivars and upon 5-, 4-, and 3-caffeoylquinic acid concentrations within cv. King Edward was determined. Storage period significantly affected (P < 0.05) the magnitude of the light-induced chlorogenic acid resp...

Glycoalkaloid and chlorophyll concentrations within tuber tissue of three potato cultivars (Desiree, King Edward and Kerrs Pink) were measured following 15 days continuous illumination (250 μmol m−2 s−1 photosynthetically active radiation). Comparisons were made of the influence of four light sources: fluorescent tube type warm white, high pressure...

The total glycoalkaloid concentration of non-sprouted potato tubers, cvs Marfona, Fianna, Maris Piper, Kestrel and Golden Wonder, was measured following 15 days of continuous illumination (250 µmol m−2 s−1 photosynthetically active radiation) using high-performance liquid chromatography. Comparisons were made of the influence of four sources of ill...

The total glycoalkaloid concentration of non-sprouted potato tubers, cvs Marfona, Fianna, Maris Piper, Kestrel and Golden Wonder, was measured following 15 days of continuous illumination (250 µmol m⁻² s⁻¹ photosynthetically active radiation) using high-performance liquid chromatography. Comparisons were made of the influence of four sources of ill...

The influence of freeze dried potato powder derived from tubers (cvs Désirée and Epicure) exposed to light as a culture medium on the growth, number and spore size of nine fungal pathogens was determined in vitro with particular emphasis on the role of glycoalkaloids. Greater reductions in pathogen growth reflected increased exposure to light of tu...

Three plant growth regulators (indole-3-acetic acid (IAA), indolebutyric acid (IBA) and naphthaleneacetic acid (NAA)) singly and in combination, were incorporated as a drench into the growing medium of containerized Alnus rubra, Sorbus aucuparia, Tilia x europea and Quercus robur following removal of half of the root system. Unpruned trees drenched...

Sodium chloride solutions were applied as a root drench to containerized Alnus cordata trees grown in freely drained or waterlogged compost substrates. Leaf chlorophyll fluorescence; cell electrolyte leakage; plant mortality; leaf necrosis; time to bud burst; and leaf, shoot, and root macronutrient concentrations were evaluated. Waterlogging using...

The composition of aerial and subterranean tubers of two potato genotypes cvs Desiree (red skin) and Epicure (white skin) was compared immediately after harvest using a range of analytical methods. Irrespective of genotype, aspartic acid, arginine, glycine, glutamic acid, histidine, leucine, serine, threonine and total amino acid concentrations wer...

The measu rement of chlorophyll fluorescence for use as a rapid diagnostic tool which detected stress interactions in Italian alder (Alnus cordata Desf.) is reported. Containerised trees in well-drained or waterlogged conditions were subjected to foliar applications of various concentrations of sodium chloride (NaCI). Measurements of leaf chlorophy...

The total glycoalkaloid concentrations in white- (cv Pentland Hawk), pink- (cv Kerrs Pink) and red- (cv Desiree) skinned potato tubers were measured following 21 days exposure to daylight using high-performance liquid chromatography. Average daytime irradiance during this period was 232 μmol m−2 s−1. Regardless of cultivar, glycoalkaloid concentrat...

The total glycoalkaloid concentrations in aerial and subterranean tubers of 14 potato genotypes were measured using high-performance liquid chromatography immediately after harvest. Post-harvest, aerial tubers from all genotypes were exposed to 144 h continuous fluorescent light; additionally three genotypes (cvs Home Guard, Kerrs Pink and Desiree)...

The total glycoalkaloid concentrations in aerial and subterranean tubers of 14 potato genotypes were measured using high-performance liquid chromatography immediately after harvest. Post-harvest, aerial tubers from all genotypes were exposed to 144 h continuous fluorescent light; additionally three genotypes (cvs Home Guard, Kerrs Pink and Desiree)...

This paper reports on the establishment success of a wide range of species in the arboretum at Auchincruive, near Ayr, Scotland. The site is of interest as it is one of only a few representative tree collections in an area of Britain with a cool, wet growing season. Information on tree performance generated by such sites is important to provide mor...

The past, present and future development of the Scottish Agricultural College Auchincruive Arboretum is discussed. Past problems include climatic and animal damage as well as vandalism and techniques used to overcome these stresses are described. Presently the collection has multiple uses for education, research and interpretative purposes. Users r...

The total glycoalkaloid concentration of dormant (non-sprouted) and sprouted potato tubers cv Pentland Hawk was measured following 13 days continuous illumination (250 μmol m−2 s−2 photosynthetically active radiation) using high-performance liquid chromatography. Comparisons were made of the influence of three sources of illumination: high-pressure...

The influence of temperature on total glycoalkaloid (TGA) synthesis in tubers exposed to light (250 jumol m“2 s”2 PAR, Photosynthetically Active Radiation) or dark environments for 96 h was examined in three potato cultivars. Following 96 h light or dark the tubers were stored without light at 5°C or 24°C and TGA concentrations monitored over the s...

The effect of increasing salinity and freezing stress singly and in combination on a range of chloro- phyll fluorescence parameters in foliar tissue of six Crataegus genotypes was examined. In general, increased stress reduced fluorescence values and absorption, trap- ping and electron transport energy fluxes per leaf reaction center and cross sect...