ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

Electronic Resource

Seasonal patterns of reproductive and vegetative sink activity in early and late maturing peach (Prunus persica) cultivars (1987)

DeJong, T. M. ; Doyle, J. F. ; Day, K. R.

Oxford, UK : Blackwell Publishing Ltd

Physiologia plantarum 71 (1987), S. 0

add to mindlist on the mindlist

Details

ISSN: 1399-3054

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: Weekly measurements of fruit growth, fruit respiration and shoot extension growth were made in the field on early (June Lady) and late (O'Henry) maturing cultivars of peach (Prunus persica L. Batsch). The seasonal patterns of fruit growth and respiration for the two cultivars were very similar except that the early maturing cultivar bloomed a few days earlier than the late cultivar and had a shorter intermediate stage (Stage II) of fruit growth. Maximum rates of fruit respiration per unit weight at 20°C were similar for both cultivars during the first two stages of fruit growth but higher for the early cultivar during the final stage of fruit growth. Maximum fruit growth rates within any particular stage of fruit growth were similar for both cultivars, but the mean fruit weight of the late cultivar was greater at the end of Stage II, because of the extended length of this stage compared to the early cultivar. The final stage of most rapid fruit growth and respiration coincided with the period of most rapid shoot extension growth in the early maturing cultivar but occurred after this period in the late maturing cultivar. Genetic selection for early fruit maturity in peach has apparently had little effect on timing of shoot growth and this may result in increased competition between vegetative and reproductive sinks during peak periods of fruit growth in early maturing cultivars.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1399-3054.1987.tb04621.x

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

2

Electronic Resource

Partitioning of leaf nitrogen with respect to within canopy light exposure and nitrogen availability in peach (Prunus persica) (1989)

DeJong, T. M. ; Day, K. R. ; Johnson, R. S.

Springer

Trees 3 (1989), S. 89-95

add to mindlist on the mindlist

Details

ISSN: 1432-2285

Keywords: Nitrogen partitioning ; Photosyn thesis ; Light acclimation

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Summary Relationships between leaf nitrogen content and within canopy light exposure were studied in mature nectarine peach trees (Prunus persica cv. Fantasia) that had received 0, 112, 196, 280 or 364 kg of fertilizer nitrogen per hectare per year for the previous 3 years. The relationships between light saturated leaf CO2 assimilation rates and leaf nitrogen concentration were also determined on trees in the highest and lowest nitrogen fertilization treatments. The slope of the linear relationship between leaf N content per unit leaf area and light exposure was similar for all nitrogen treatments but the y-intercept of the relationship increased with increasing N status. The slope of the relationship between leaf N content per unit leaf area and light saturated CO2 assimilation rates was greater for the high N trees than the low N trees, but maximum measured leaf CO2 assimilation rates were similar for both the high and low N treatments. A diagrammatic model of the partitioning of leaf photosynthetic capacity with respect to leaf light exposure for high and low nitrogen trees suggests that the major influence of increased N availability is an increase in the photosynthetic capacity of partially shaded leaves but not of the maximum capacity of highly exposed leaves.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01021072

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

3

Electronic Resource

Partitioning of leaf nitrogen with respect to within canopy light exposure and nitrogen availability in peach (Prunus persica) (1989)

DeJong, T. M. ; Day, K. R. ; Johnson, R. S.

Springer

Trees 3 (1989), S. 89-95

add to mindlist on the mindlist

Details

ISSN: 1432-2285

Keywords: Nitrogen partitioning ; Photosyn thesis ; Light acclimation

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Summary Relationships between leaf nitrogen content and within canopy light exposure were studied in mature nectarine peach trees (Prunus persica cv. Fantasia) that had received 0, 112, 196, 280 or 364 kg of fertilizer nitrogen per hectare per year for the previous 3 years. The relationships between light saturated leaf CO2 assimilation rates and leaf nitrogen concentration were also determined on trees in the highest and lowest nitrogen fertilization treatments. The slope of the linear relationship between leaf N content per unit leaf area and light exposure was similar for all nitrogen treatments but the y-intercept of the relationship increased with increasing N status. The slope of the relationship between leaf N content per unit leaf area and light saturated CO2 assimilation rates was greater for the high N trees than the low N trees, but maximum measured leaf CO2 assimilation rates were similar for both the high and low N treatments. A diagrammatic model of the partitioning of leaf photosynthetic capacity with respect to leaf light exposure for high and low nitrogen trees suggests that the major influence of increased N availability is an increase in the photosynthetic capacity of partially shaded leaves but not of the maximum capacity of highly exposed leaves.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00191539

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

4

Electronic Resource

Change in proportion of larval colourtypes of the larchform Zeiraphera diniana when reared on two media (1972)

Day, K. R. ; Baltensweiler, W.

Springer

Entomologia experimentalis et applicata 15 (1972), S. 287-298

add to mindlist on the mindlist

Details

ISSN: 1570-7458

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Description / Table of Contents: Zusammenfassung Im Verlaufe einer Massenvermehrung des Grauen Lärchenwicklers verändern sich die relativen Anteile der larvalen Farbtypen. Es wurde vermutet, daß diese Erscheinung mit der dichtebedingten Schädigung der Wirtspflanze und einer nachfolgenden Änderung der Nahrungsqualität gekoppelt sei. Zwecks Abklärung dieser Hypothese wählte man aus Freiland-populationen Individuen bestimmter Farbtypen aus und züchtete die F1-Generation auf frischen Kurztrieben der Lärche und auf einem semi-synthetischen Nährmedium. Es konnte gezeigt werden, daß nicht nur die Larval-Mortalitäten auf den beiden Nährmedien voneinander abweichen, sondern daß auch die Anteile der Farbtypen in den entsprechenden Gruppen verschieden sind. Die Versuche lassen schließen, daß unter. Nahrungsstress die dunklen Farbtypen während der frühen Larvenstadien eine höhere Mortalität erleiden und somit die Selektion zu einem Wechsel in der Zusammensetzung der Farbtypen der folgenden Generation beiträgt. Zusätzlich beobachtet man aber, daß unter Nahrungsstress die Übereinstimmung zwischen dem elterlichen Farbtyp und jenem der Nachkommen größer ist. Somit bekräftigen die Resultate die Annahme einer variablen Leistungsfähigkeit der Population in bezug auf Nahrungsstress während einer Massenvermehrung.

Notes: Abstract In the course of a population cycle of the Grey Larch Bud Moth it was observed that the proportions of larval colourtypes change. This was believed to be attributable to density induced changes in the food quality of the host plant during the cycle. Selected representatives of naturally occurring larval populations were reared in controlled laboratory conditions on freshly cut larch shoots and on a semi-synthetic food medium. Larval mortality on the laboratory culture media was shown to be different and the proportions of colour forms in the resultant and corresponding groups also differed. These experiments suggest higher mortality of early-instar larvae of the dark colourtype under food-stress conditions and a resulting change in colourtype composition of the next generation. Further to this there is an indication that effective true-breeding is more likely under food-stress conditions. The results support the hypothesis for a changing population fitness with regard to food-stress conditions throughout a gradation cycle.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00428293

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

5

Electronic Resource

Predicting the extent of damage to conifer seedlings by the pine weevil (Hylobius abietis L.): a preliminary risk model by multiple logistic regression (1996)

Wilson, W. L. ; Day, K. R. ; Hart, E. A.

Springer

New forests 12 (1996), S. 203-222

add to mindlist on the mindlist

Details

ISSN: 1573-5095

Keywords: forest ; risk assessment

Source: Springer Online Journal Archives 1860-2000

Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract Damage to conifer seedlings caused by the pine weevil, Hylobius abietis, was estimated within eighty-two forest sites in Northern Ireland. A wide range of environmental variables were compared with the variation in damage between study sites using multiple logistic regression. Although 45 explanatory variables were considered only four were identified as significant within the final model. The four variables were the size of the planted area, the age of the planting, whether the majority of seedlings were self-seeded or planted, and if the site had been previously planted or was a newly planted area. The identification of these four variables indicates that it is possible to build a model identifying areas at risk to weevil damage. Further, although three of the factors have been recognised as significant influences on weevil damage for some time, they still remain important variables within British Isles forestry, suggesting that there is further scope for more precise targeting of weevil control measures.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00027932

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

6

Electronic Resource

Cormorant (Phalacrocorax carbo [L]) populations and patterns of abundance at breeding and feeding sites in Northern Ireland, with particular reference to Lough Neagh (1994)

Warke, G. M. A. ; Day, K. R. ; Greer, J. E. ; [et al.]

Springer

Hydrobiologia 279-280 (1994), S. 91-100

add to mindlist on the mindlist

Details

ISSN: 1573-5117

Keywords: cormorants ; roach ; populations

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract Breeding cormorants, Phalacrocorax carbo, in Northern Ireland remain seasonally dependent on a coastal environment where they can be censused with accuracy, but numbers in other habitats and at other times of the year are less certain. This study establishes the long term and regional patterns of abundance at breeding and feeding localities, which might in turn be related to diet. Birds were regularly observed and counted at a variety of feeding sites, and some aspects of their breeding success and fledgling diet evaluated at the largest N.Ireland breeding colony. Numbers of breeding birds increased dramatically over a period of eight years but recently show signs of declining. There is likely to be a dynamic relationship between populations of a tapeworm (Ligula intestinalis L.), the numbers of roach (Rutilus rutilus [L.]) and cormorant populations feeding at Lough Neagh, the largest lake in the British Isles. While roach are not a major component in the diet of fledglings, the large numbers of cormorants feeding at the perimeter of L. Neagh suggest that changes in roach populations will affect birds most acutely during or following the winter. We suggest that this might result in a reduction in the proportion of the population volunteering to breed in the subsequent season, but require further data. The longer term effects of one fish species on cormorant populations are unlikely to be critical, since these birds are highly opportunist. In other habitats cormorant numbers are either very stable (estuary) or variable (river) depending on the seasonal and annual availability of their prey. There is no evidence for a systematic seasonal shift in habitat, as suggested by other studies.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00027844

Permalink