P. E. Kriedemann

Bio: P. E. Kriedemann is an academic researcher from Commonwealth Scientific and Industrial Research Organisation. The author has contributed to research in topics: Photosynthesis & Berry. The author has an hindex of 5, co-authored 5 publications receiving 241 citations.

Photosynthesis in vine leaves as a function of light intensity, temperature, and leaf age

Abstract: Photosynthesis and respiration were measured in the laboratory with an infrared CO 2 analyser using attached leaves on Sultana vines growing either in the glasshouse or out of doors At light saturation (2,500-3,000 f c) the photosynthetic rates approximated 85 and 105 mg CO/h/dm 2 with light compensation points of 50 and 125 f c respectively The optimum temperature for photosynthesis was between 25 and 30° C Age effects were examined using shoots from well established field vines Small but rapidly expanding terminal leaves showed no net photosynthesis but had a high rate of dark respiration and a CO 2 compensation point above 300 ppm With further expansion the leaves showed a steady increase in photosynthetic activity with a corresponding decline in dark respiration and CO 2 compensation point The rate of photosynthesis again declined with the onset of senescence

Leaf age and photosynthesis in Vitis vinifera L.

Abstract: The photosynthetic activity of individual vine leaves was measured on potted plants grown out doors, using both infrared C0 2 analysis and 14 C0 2 fixation techniques. Peak photosynthetic activity occurred at the time when the leaf became fully expanded, approximately 40 days after unfolding. Thereafter, photosynthesis declined gradually. The increase in photosynthesis during leaf expansion was not attributable to increased chlorophyll concentration, altered spectral characteristics, or to any outstanding anatomical change. Nevertheless, a sensecent leaf was readily distinguished anatomically from an expanding or mature leaf.Irrespective of leaf age, sucrose was the major 14 C0 2 fixation product. Oligo- saccharides also incorporated label, and accounted for a higher proportion of the 14 C fixation products in older leaves. Regardless of leaf age, malic and citric acids became labelled, but the formation of 14 C tartaric acid was restricted to the rapidly expanding foliage. The amino compounds serine and aspartic acid showed some incorporation of label in all leaves examined.

Anatomical aspects of grape berry development

Abstract: The anatomical development of the sultana-grape berry has been followed from anthesis to maturity on material grown under glasshouse and field conditions including field-grown clonal lines differing in final fruit size. Fresh weight, volume, berry dimensions, moisture content and dry weight were measured on whole berries. Pericarp growth was studied at the cell level. Pericarp growth is basically responsible for the overall growth of the berry and this tissue represents 64% of the mature fruit's total volume. The period required for complete berry development (approximately 100 days) falls into two major growth periods separated by a lag phase. Before the lag phase pericarp growth results partly from cell division but mainly from cell enlargement. After the lag phase pericarp growth results entirely from cell enlargement. Cell division in the pericarp ceases about one week before the lag phase. Berry size differences between clonal lines were primarily due to differences in the size of pericarp cells. Berry size differences between fruits grown in the glasshouse and in the field at Merbein were due to differences in both pericarp cell number and cell size.

Grape berry respiration: Effects of metabolic inhibitors

Abstract: The rate of O 2 uptake, respiratory quotient and the effects of metabolic inhibitors on respiration were followed throughout berry development of 4 varieties of Vitis vinifera L. No obvious differences in respiratory characteristics were found between seeded and seedless and between pigmented and nonpigmented grapes. Physiological differences between immature and maturing grape berries involve altered rates of respiration and a changed sensitivity to metabolic inhibitors. With development in all varieties there was a decline in O 2 uptake on a fresh weight basis while R.Q. values rose to greater than unity. Dinitrophenol failed to stimulate O, uptake at any stage and the inhibition of O 2 uptake caused by azide or DNP was more severe in mature fruit than in immature fruit. Cyanide stimulated O 2 uptake in tissue slices from immature Sultana berries but inhibited O 2 uptake in slices from more developed fruit. These data, coupled with the absence of any major alteration in the level of insoluble nitrogen per unit fresh weight of berry suggest that respiration is both quantitatively and qualitatively different in immature compared with maturing grape berries.

The response of vine leaf photosynthesis to shoot tip excision and stem cincturing

Abstract: The photosynthetic activity of mature leaves on glasshouse grown vines was measured in the laboratory 7-8 days after applying 4 treatments designed to vary the plant's demand for assimilates. These comprised shoot tip excision, stem cincturing and a combination of the two. The elimination of roots as an effective sink for assimilate led to assimilate build-up in leaves and caused a consistent reduction in photosynthesis, compared to control vines, regardless of whether shoot tips had been retained or previously excised. Excision of shoot tips did not elicit a consistent, photosynthetic response in remaining leaves. Der Einflus des Gipfelns und Ringelns auf die Photosynthese des Rebenlaubes Um den Assimilatbedarf von Reben zu verandern, wurden die Triebspitzen von Gewachshauspflanzen gegipfelt, die Triebe geringelt oder beide Eingriffe kombiniert vorgenommen. 7-8 Tage danach wurde die Photosyntheseaktivitat reifer Blatter im Labor gemessen. Die Ausschaltung der Wurzeln als wichtiges ,,sink" fuhrte zur Anhaufung von Assimilaten in den Blattern und verursachte in -Obereinstimmung damit einen Ruckgang der Photosynthese gegenuber den unbehandelten Reben, unabhangig davon, ob die Triebspitzen vorher entfernt worden waren oder nicht. Eine entsprechende Wirkung auf die Photosynthese der verbliebenen Blatter wurde durch das Gipfeln nicht hervorgerufen.

Constraints on Leaf Structure and Function in Reference to Herbivory

Abstract: Leaves vary considerably in their physical and physiological properties. Although there have been advances in our understanding of the significance of their shapes (Gates and Papian 1971, Gilbert 1975, Givnish 1979, Wiens 1978) and appendages of leaves (Gilbert 1971, Ehleringer et al. 1976), we still do not have a comprehensive understanding of the evolutionary significance of variability in such physiological and developmental properties as leaf growth, metabolic rates, or longevity. The variation in a number of leaf properties is related to both environmental resource levels and patterns of herbivory. To place our discussion in an evolutionary context, we consider the benefit a plant derives from a leaf to be the rate of leaf carbon gain, times the carbon gain period, minus the carbon cost of leaf growth and maintenance and the losses due to herbivory. All of these components, with the exception of herbivory, can be evaluated in terms of the rates of carbon dioxide exchange of leaves (Figure 1).

Managing grapevines to optimise fruit development in a challenging environment: a climate change primer for viticulturists

Abstract: Grapevine reproductive development extends over two seasons, and the genotypic expression of yield potential and fruit composition is subject to environmental impacts, which include viticultural manipulations, throughout this period. This paper reviews current knowledge on yield formation and fruit composition and attempts to identify challenges, opportunities and priorities for research and practice. The present analysis of published information gives a critical appraisal of recent advances concerning variables, especially as they relate to global climate change, that influence yield formation and fruit composition at harvest. Exciting discoveries in fundamental research on the one hand and an increasing focus on outcomes and knowledge transfer on the other are enabling the development and implementation of practical recommendations that will impact grape production in the future. Future research should aim to minimise seasonal variation and optimise the profitable and sustainable production of high-quality fruit for specific uses in the face of climate change, water and labour shortages, shifting consumer preferences and global competition. Better control of product quantity and quality, and differentiation to meet consumer demands and market preferences will enhance the competitiveness and sustainability of the global grape and wine industries.

Wine aroma compounds in grapes: a critical review.

Abstract: Volatile organic compounds are vital to wine quality, determining their aroma and varietal characteristics. Which are present, and in what quantity, depends on the cultivar, the situation and soil of the vineyard, weather, cultivation methods, and wine-making practices. Here, we review the literature on the development of wine aroma compounds in grapes, and how it is affected by the above-named factors. Increasing understanding of these processes at the molecular level will aid vine growers in the optimal selection of harvest dates and other decisions favoring the consistent production of balanced, flavorful berries.

Photosynthesis in Salt-Stressed Grapevines

Abstract: Rooted cuttings of grapevine (Vitis vinifera L. cv. Sultana syn. Thompson Seedless) were grown in sand culture irrigated with nutrient solution containing 1-125 mM NaCl. The effect of salinity on vine growth and photosynthesis is described. Salinity led to reduced growth where foliar symptoms of salt toxicity were absent. Rates of CO2 fixation decreased with increasing levels of chloride in leaves. This decrease in photosynthesis could be largely attributed to increased residual (mesophyll) resistance to CO2 fixation. Radiotracer studies showed that salt stress led to the accumulation of label in intermediates of the glycollate pathway. Salt-stressed leaves contained decreased amounts of sucrose and starch, but increased levels of reducing sugars.