A nondestructive optical method for determining the soluble solids content of fresh whole tomatoes was investigated. The method, based upon near infrared spectrophotometric techniques, could predict the soluble solids content of tomatoes (r ϭ 0.92, SEC ϭ 0.27ЊBrix). Tomatoes from more than 30 popular fresh market cultivars at stages of maturity from mature green to ripe red fruit were studied.

Sucrose synthesis is a major element of the interactions between photosynthesis and plant growth and development. Tomato (Lycopersicon esculentum Mill. cv. UC82B) plants transformed with maize sucrose-phosphate synthase (SPS; EC 2.3.1.14) expressed from either a ribulose-1,5-bisphosphate carboxylaseoxygenase (Rubisco) small subunit promoter (SSU) or the cauli¯ower mosaic virus 35S promoter (35S) were used to study eects of increased sucrose synthesis rates on plant growth. The plants were grown in growth chambers, ®eld plots, and open-top chambers. The 35S plants had a 2 to 3-fold increase in young-leaf SPS activity, a 10 to 20-fold increase in young-root SPS activity and no increase in young-fruit SPS activity. The leaf SPS activity in one of the 35S lines fell to control levels by two months of age. The SSU plants had a 4 to 5-fold increase in leaf SPS activity and no signi®cant increase in root or young-fruit SPS activity. One 35S line, which maintained high leaf SPS activity throughout development, yielded 70±80% more than controls at both normal and elevated CO 2 in open-top chambers in the ®eld and 20±30% more than controls in two additional ®eld trials. The other 35S line and the two SSU lines either yielded less or did not dier from controls under several growth conditions. Since only one of four transformed lines showed an increase in yield, we can not yet conclude that increased leaf SPS activity leads to increased yield. However, increased leaf SPS activity appears to result in increased fruit sugar content since all three lines with increased leaf SPS usually also had increased fruit sugars.Key words: Cauli¯ower mosaic virus 35S promoter ± Growth chamber (open topped) Lycopersicon ± Open top chambers ± Ribulose-1,5-bisphosphate carboxylase-oxygenase small subunit promoter ± Sucrose-phosphate synthase ± Yield (transformed tomato) Abbreviations: DAS = days after seeding; SPS = sucrosephosphate synthase; SSU = small subunit of Rubisco Correspondence to: M. Laporte;

Transformation of Sprague-Dawley rat embryo (RE) cells and a cloned Fischer rat embryo cell line (CREF) with wild-type (Ad5) or a temperature-sensitive DNA-minus mutant (H5ts125) of type 5 adenovirus results in a reduction in binding of epidermal growth factor (EGF) to cell surface receptors. A reduction in EGF binding is also seen in a Syrian hamster embryo cell line transformed by a hexon mutant of Ad5. In contrast, a human embryonic kidney cell line (293) transformed by sheared Ad5 DNA or transfected clones of KB cells expressing the E1 transforming region of Ad5 do not show a decrease in receptor binding. When cocultivated, the adenovirus transformed rat cells were able to induce the growth in agar of normal CREF cells. Medium from Ad5 transformed RE cells stimulated the growth in agar of CREF cells and also inhibited [125I]-EGF binding in CREF cells. When fractionated by gel filtration, two peaks of [125I]-EGF inhibiting activities were obtained with apparent molecular weights of 35,000 and 16,000. These results provide the first evidence that cells transformed by an adenovirus can produce a growth factor(s) that inhibits EGF-receptor binding and induces anchorage-independent growth of normal cells.

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The extinction point (EP), defined as the lowest O2 concentration at which alcohol production ceases, was a useful concept in early interpretations of the Pasteur effect in fruit. However, ethanol is now known to be a normal constituent of many fruits under aerobic conditions. Therefore, we propose an alternative concept, the anaerobic compensation point (ACP), defined as the O2 concentration at which CO2 evolution is minimum. After 2 to 4 hr under various O2 concentrations, the ACPs of mature-green pears (Pyrus communis L.) and pear cell cultures are 1.6% to 1.7% and 1.1% to 1.3% O2, respectively. The ACP shifts to lower O2 concentrations upon extended exposure of the cells to low-O2 atmospheres and to higher O2 concentrations as pear fruit mature physiologically or as the diffusion coefficient of cell suspensions is decreased. With O2 diffusion coefficients of 4.4, 3.7, and 2.5 × 10−6 cm2·s−1, the ACP effect is observed just below 1.3%, 3.0%, and 5.0% O2, respectively. Analogies between the responses of intact fruit and suspension-cultured cells to limiting O2 are illustrated and use of the latter in assessing the response of pear cells to changing coefficients of diffusion is discussed.