How rainfall, relative humidity and temperature influence volatile emissions from apple trees in situ.

Headspace volatiles from apple-bearing twigs were collected in the field with a Radiello sampler during three different diurnal periods over the complete fruit growing season. Analyses by thermal desorption-GC-MS identified a total of 62 compounds in changing quantities, including the terpenoids alpha-pinene, camphene, beta-pinene, limonene, beta-caryophyllene and (E,E)-alpha-farnesene, the aldehydes (E)-2-hexenal, benzaldehyde and nonanal, and the alcohol (Z)-3-hexen-1-ol. The variations in emission of these plant odours were statistically related to temperature, humidity and rainfall in the field. Remarkably, rainfall had a significant positive influence on changes in volatile release during all three diurnal periods, and further factors of significance were temperature and relative humidity around noon, relative humidity in the late afternoon, and temperature and relative humidity during the night. Rainfall was associated consistently with an increase in the late afternoon in terpene and aldehyde volatiles with a known repellent effect on the codling moth, one of the key pests of apple fruit. During the summer of 2003, a season characterized by below-average rainfall, some postulated effects of drought on trees were tested by establishing correlations with rainfall. Emissions of the wood terpenes alpha-pinene, beta-pinene and limonene were negatively correlated with rainfall. Another monoterpene, camphene, was only detected in this summer but not in the previous years, and its emissions were negatively correlated with rainfall, further supporting the theory that drought can result in higher formation of secondary metabolites. Finally, the two green leaf volatiles (E)-2-hexenal and (Z)-3-hexen-1-ol were negatively correlated with rainfall, coinciding well with the expectation that water deficit stress increases activity of lipoxygenase. To our knowledge, this work represents the first empirical study concerning the influence of abiotic factors on volatile emissions from apple trees in situ.

[1]  G. Vernin,et al.  Analysis of the Volatile Compounds of Psidium cattleianum Sabine Fruit from Reunion Island , 1998 .

[2]  John H. Loughrin,et al.  Diurnal cycle of emission of induced volatile terpenoids by herbivore-injured cotton plant. , 1994, Proceedings of the National Academy of Sciences of the United States of America.

[3]  T. C. Hennessey,et al.  Physiology and genetics of tree growth response to moisture and temperature stress: an examination of the characteristics of loblolly pine (Pinus taeda L.). , 1987, Tree physiology.

[4]  J. Takabayashi,et al.  Volatile herbivore-induced terpenoids in plant-mite interactions: Variation caused by biotic and abiotic factors , 1994, Journal of Chemical Ecology.

[5]  P. Lea,et al.  Influence of temperature and plant density on sensory quality and volatile terpenoids of carrot (Daucus carota L.) root , 2002 .

[6]  F. Loreto,et al.  Influence of Environmental Factors and Air Composition on the Emission of [alpha]-Pinene from Quercus ilex Leaves , 1996, Plant physiology.

[7]  S. Dorn,et al.  Plant-odour mediates parasitoid host handling and oviposition in an endophytic tritrophic system , 2000, CHEMOECOLOGY.

[8]  K. Furukawa,et al.  Volatile components of apple flowers , 1990 .

[9]  R. Hofstetter,et al.  Apple Fruit Infested with Codling Moth are More Attractive to Neonate Codling Moth Larvae and Possess Increased Amounts of (E,E)-α-Farnesene , 2004, Journal of Chemical Ecology.

[10]  J. Fellman,et al.  Volatile Constituents of Bing Sweet Cherry Fruit following Controlled Atmosphere Storage , 1997 .

[11]  R. Rikala,et al.  Drought Stress Alters the Concentration of Wood Terpenoids in Scots Pine and Norway Spruce Seedlings , 2003, Journal of Chemical Ecology.

[12]  E. Grosjean,et al.  Ambient levels of gas phase pollutants in Porto Alegre, Brazil , 1998 .

[13]  S. Dorn,et al.  Sexual dimorphism in the olfactory orientation of adult Cydia pomonella in response to α‐farnesene , 1999 .

[14]  T. C. Turlings,et al.  The Effects of Abiotic Factors on Induced Volatile Emissions in Corn Plants1 , 2002, Plant Physiology.

[15]  S. Dorn,et al.  Induction of volatile emissions from ripening apple fruits infested with Cydia pomonella and the attraction of adult females , 2002 .

[16]  Harold A. Mooney,et al.  Responses of Plants to Multiple Stresses , 1993 .

[17]  P. Dimick,et al.  Review of apple flavor--state of the art. , 1983, Critical reviews in food science and nutrition.

[18]  J. Peñuelas,et al.  Pinus Halepensis and Quercus Ilex Terpene Emission as Affected by Temperature and Humidity , 1999, Biologia Plantarum.

[19]  R. Altenburger,et al.  Further observations on rhythmic emission of fragrance in flowers , 2004, Planta.

[20]  G. Buchbauer,et al.  Headspace and essential oil analysis of apple flowers , 1993 .

[21]  E. Schulze,et al.  4 – Water and Nutrient Interactions with Plant Water Stress , 1991 .

[22]  S. Dorn,et al.  Volatiles emitted by apple fruitlets infested by larvae of the European apple sawfly , 1996 .

[23]  H. Linskens,et al.  Analysis of Taste and Aroma , 2002, Molecular Methods of Plant Analysis.

[24]  Stephen K. Brown,et al.  Concentrations of Volatile Organic Compounds in Indoor Air – A Review , 1994 .

[25]  F. Marion-Poll,et al.  Detection of Physiologically Active Flower Volatiles Using Gas Chromatography Coupled with Electroantennography , 2002 .

[26]  D. Treutter,et al.  Bioactive components in fruits from different apple varieties , 2003 .

[27]  M. Bengtsson,et al.  Behavioral Response of Female Codling Moths, Cydia pomonella, to Apple Volatiles , 1999, Journal of Chemical Ecology.

[28]  E. Ibáñez,et al.  Supercritical fluid extraction and fractionation of different preprocessed rosemary plants. , 1999, Journal of agricultural and food chemistry.

[29]  J. Mattheis,et al.  Drought stress of apple trees alters leaf emissions of volatile compounds , 1995 .

[30]  S. van Straten,et al.  Volatile compounds in food. , 1977 .

[31]  J. Siedow.  PLANT LIPOXYGENASE: STRUCTURE AND FUNCTION , 1991 .

[32]  S. Dorn,et al.  Changes in volatile emissions from apple trees and associated response of adult female codling moths over the fruit-growing season. , 2005, Journal of agricultural and food chemistry.

[33]  R. Baraldi,et al.  Seasonal variation of monoterpene emission from Malus domestica and Prunus avium. , 2001, Phytochemistry.

[34]  Philip O. Owuor.  Changes in quality parameters of commercial black seedling tea due to the time of the year in the Eastern Highlands of Kenya , 1992 .

[35]  J. Pino,et al.  Volatile constituents of star apple (Chrysophyllum cainito L.) from Cuba , 2002 .

[36]  M. Vendrell,et al.  COMPARISON OF VOLATILE COMPOUNDS IN TWO SEASONS IN APPLES: GOLDEN DELICIOUS AND GRANNY SMITH , 1998 .

[37]  H. Mactavish,et al.  Emission of floral volatiles from Mahonia japonica (Berberidaceae). , 2002, Phytochemistry.

[38]  S. Dorn,et al.  Monitoring seasonal variation in apple fruit volatile emissions in situ using solid-phase microextraction. , 2003, Phytochemical analysis : PCA.

[39]  R. Raguso,et al.  Dynamic headspace analysis of floral volatiles: A comparison of methods , 1998 .

[40]  P. Etiévant,et al.  The volatile constituents of strawberry jam , 1990 .

[41]  S. Dorn,et al.  Global and regional pest insects and their antagonists in orchards: spatial dynamics , 1999 .

[42]  S. Dorn,et al.  Statistical modelling of insect behavioural responses in relation to the chemical composition of test extracts , 2001 .

[43]  L. Grothaus,et al.  Influence of light and temperature on monoterpene emission rates from slash pine. , 1980, Plant physiology.

[44]  J. Peñuelas,et al.  Seasonal patterns of terpene content and emission from seven Mediterranean woody species in field conditions. , 2000, American journal of botany.

[45]  H. Young,et al.  Characterization of Royal Gala apple aroma using electronic nose technology-potential maturity indicator. , 1999, Journal of agricultural and food chemistry.

[46]  V. Bashkin,et al.  Review: Behavior of Persistent Organic Pollutants in the Air-Plant-Soil System , 2002 .

[47]  P. Schreier,et al.  Volatile constituents from the peelings of lulo (Solanum vestissimum D.) fruit , 1993 .

[48]  M. Dicke,et al.  Multitrophic effects of herbivore‐induced plant volatiles in an evolutionary context , 2000 .

[49]  D. Hildebrand,et al.  Volatiles from flowers of Nicotiana sylvestris, N. otophora and Malus × domestica: headspace components and day/night changes in their relative concentrations. , 1990 .

[50]  Richard Karban,et al.  Induced Responses to Herbivory , 1997 .

[51]  C. Galán,et al.  Forecasting olive (Olea europaea) crop yield based on pollen emission , 2004 .