Search Results

You are looking at 51 - 60 of 1,808 items for :

  • chlorophyll x
  • All content x
Clear All
Full access

Keun H. Cho, Veronica Y. Laux, Nathan Wallace-Springer, David G. Clark, Kevin M. Folta, and Thomas A. Colquhoun

measurement. The plants were dried inside an oven at 75 °C for 48 h and weighed. Leaf chlorophyll pigment was extracted from 100 mg of fresh leaves at 65 °C for 30 min in a 10-mL dimethyl sulfoxide solution (Thermo Fisher Scientific Inc., Hampton, NH). Each

Free access

Robert K. Prange, John M. DeLong, Peter A. Harrison, Jerry C. Leyte, and Scott D. McLean

A new chlorophyll fluorescence (F) sensor system called FIRM (fluorescence interactive response monitor) was developed that measures F at low irradiance. This system can produce a theoretical estimate of Fo at zero irradiance for which we have coined a new fluorescence term, Fα. The ability of Fα to detect fruit and vegetable low-O2 stress was tested in short-term (4-day) studies on chlorophyll-containing fruit [apple (Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.), pear (Pyrus communis L.), banana (Musa ×paradisiaca L.), kiwifruit (Actinidia deliciosa C.S. Liang & A.R. Ferguson), mango (Mangifera indica L.), and avocado (Persea americana Mill.)] and vegetables (cabbage (Brassica oleracea L. Capitata Group), green pepper (Capsicum annuum L. Grossum Group), iceberg and romaine lettuce (Lactuca sativa L.)). In all of these fruit and vegetables, Fα was able to indicate the presence of low-O2 stress. As the O2 concentration dropped below threshold values of 0 to 1.4 kPa, depending on the product, the Fα value immediately and dramatically increased. At the end of the short-term study, O2 was increased above the threshold level, whereupon Fα returned to approximately prestressed values. A 9-month study was undertaken with `Summerland McIntosh' apple fruit to determine if storing the fruit at 0.9 kPa O2, the estimated low O2 threshold value determined from Fα, would benefit or damage fruit quality, compared with threshold + 0.3 kPa (1.2 kPa O2) and the lowest recommended CA (1.5 kPa O2). After 9 months, the threshold treatment (0.9 kPa) had the highest firmness, lowest concentration of fermentation volatiles (ethanol, acetaldehyde, ethyl acetate) and lowest total disorders. Sensory rating for off-flavor, flavor and preference indicated no discernible differences among the three treatments.

Free access

Valentina Schmitzer, Maja Mikulic-Petkovsek, Franci Stampar, and Vlasta Cunja

, carotenoids, chlorophylls, and flavonols are the major contributors to astonishing color diversity of flowers, and their content often changes during flower senescence ( Schmitzer et al., 2010 ; Slatnar et al., 2013 ; Sood and Nagar, 2003 ). Moreover, petal

Free access

David A. Felicetti and Larry E. Schrader

chlorophyll and carotenoid analysis, and two disks were used for phenolic analysis. Thus, each degree (class) of sunburn had 10 repetitions, with each repetition composed of two peel disks from the same apple. In 2006, 20 apples of sunburn degrees 0 to 4 were

Free access

Xingbin Xie, Congbing Fang, and Yan Wang

flavor and texture, fruit characteristic skin color is important for consumer acceptance and often an indicator for ripening of european pears ( Charoenchongsuk et al., 2015 ; Kappel et al., 1995 ). Yellowing caused by chlorophyll degradation in storage

Free access

Robert E. Rouse

The Minolta chlorophyll meter SPAD-502 (Minolta Camera Company, 101 Williams Drive, NJ 07446, USA) has been found to be a quick, accurate, simple, and nondestructive way to determine chlorophyll content in citrus leaves and a standard curve had been developed. The SPAD-502 chlorophyll meter was used to measure chlorophyll content in citrus leaves of ten varieties on three rootstocks. Leaf mineral analysis was then determined on these leaves for N, P, K, Mg, Mn, Zn, Fe, Cu and Ca. Correlation r values were generally low and not significant for most nutrient elements but were highest for Fe and Ca. The relationship of leaf nutrient levels and chlorophyll meter readings are not understood. The usefulness of the SPAD chlorophyll meter for determining mineral content in citrus leaves is not yet known.

Free access

E.J. Ryder, Z.H. Kim, and W. Waycott

Three mutant traits for chlorophyll deficiency in lettuce (Lactuca sativa L.), bleached bud, calico-2, and pale green, are inherited as single recessive alleles. Bleached bud is epistatic to another recessive allele, dappled. Calico-2 is epistatic to dappled. Pale green is hypostatic to chlorophyll deficient-3. The Vanguard cd mutant is the same as chlorophyll deficient-3. The light green mutant 8744-1 is the same as light green. Independent inheritance is shown for bleached bud and dappled, calico-2 and dappled, and pale green and chlorophyll deficient-3, respectively.

Free access

Fan Zhang, Zi Wei, Peter Jeranyama, Carolyn DeMoranville, and Harvey J.M. Hou

, including spectrometry, high-performance liquid chromatography (HPLC), and chlorophyll fluorescence kinetics to examine cranberry leaves with yellow vine syndrome and normal cranberry leaves to provide novel insight into the underlying mechanism causing the

Free access

Kui Lin, Zhi Huang, and Yong Xu

techniques of plant physiological biochemical experiment, p. 190–192. Higher Educ. Press, Beijing, China (in Chinese) Wang, H. Gu, M. Cui, J.X. Shi, K. Zhou, Y.H. Yu, J.Q. 2009 Effects of light quality on CO 2 assimilation, chlorophyll-fluorescence quenching

Full access

W.C. Lin, J.W. Hall, and A. Klieber

A video-imaging technique, using commercial software to process images obtained at 550 nm, was established to estimate chlorophyll content of cucumber fruit disks. The chlorophyll content of excised disks was extracted, determined, and regressed on the video-image grey level. They were linearly related. The change in grey level of the whole visible image accurately indicated the change of green color during fruit development on the vine and the loss of green color after 1 week of storage at 13C. The relationship of the chlorophyll content on grey level was quadratic for three imaging methods: 1) average grey level of the five disks; 2) average grey level of the whole cucumber image; and 3) average grey level of central one-third of the whole cucumber image. Chlorophyll content was most highly correlated to the grey level of the disks themselves (residual SD = 6.74 μg·cm-2), but this sampling technique was destructive. Both one-third of the fruit image (SD = 9.25 μg·cm-2) and the whole image (SD = 9.36 μg·cm-2) provided satisfactory precision. For simplicity, whole-fruit imaging is suitable for estimating fruit chlorophyll content and for quantifying fruit green color intensity. Potential use of this technique in product sorting and shelf life prediction of long English cucumbers is discussed.