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Astrid Kubatsch, Heiner Grüneberg, and Christian Ulrichs

, leaves had higher chlorophyll content than leaves of plants grown in the sun ( Lance and Guy, 1992 ; Reyes et al., 1996 ). The leaf thickness of Pelargonium × hortorum was reduced by increasing temperatures from 10 °C to 32 °C ( Armitage et al., 1981

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Jacques R. Fouché, Stephanie C. Roberts, Stephanie J.E. Midgley, and Willem J. Steyn

necrosis ( Felicetti and Schrader, 2008 ). Chlorophyll levels decreased as a result of sunburn in all apple cultivars studied ( Felicetti and Schrader, 2009 ). Red blush in GS is formed when anthocyanin synthesis is stimulated by low night temperature and

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Haiyan Zhao, Haiying Liang, Yibing Chu, Congcong Sun, Ning Wei, Mengnan Yang, and Caixia Zheng

.0%-treated groups at 64 d for Car. Fig. 1. Leaves and stems of 3-year-old ginkgo seedlings grown under various NaCl concentrations (0%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%) after 64 d. Fig. 2. ( A–D ) Effect of NaCl on the contents of chlorophyll (Chl) and

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Graham H. Barry and Smit le Roux

chlorophyll and increased carotenoid concentrations in the flavedo of the rind ( Eilati et al., 1969 ; Goldschmidt, 1988 ). These changes in rind pigments are mainly the result of the senescence of chlorophyllous tissue in the flavedo and result in the

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Jong-Goo Kang, Rhuanito Soranz Ferrarezi, Sue K. Dove, Geoffrey M. Weaver, and Marc W. van Iersel

side effect could limit the usefulness of ABA as a commercial holding agent ( Kim and van Iersel, 2011 ; van Iersel et al., 2009 ; Waterland et al., 2010a ; Weaver and van Iersel, 2014 ). Nitrogen is an essential component of chlorophyll, and leaf

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Jiangbo Dang, Tingrong Wu, Guolu Liang, Di Wu, Qiao He, and Qigao Guo

scions. Height, stem thickness, internode length, leaf length, and leaf width of grafted scions of the tree lines were measured on grafted seedlings (8 months old). The leaves on middle shoots of the scions were used for the measurements. Chlorophyll

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Sarah E. Bruce, D. Bradley Rowe, and James A. Flore

Chlorophyll fluorescence over the course of stem cutting propagation was examined in 10 cultivars of Taxus ×media (Taxus baccata L. × T. cuspidata Sieb. & Zucc.), including `Brownii', `Dark Green Pyramidalis', `Dark Green Spreader', `Densiformis', `Densiformis Gem', `Hicksii', `L.C. Bobbink', `Runyan', `Tauntoni', and `Wardii'. The fluorescence value measured was the ratio of variable over maximum chlorophyll fluorescence (Fv/Fm). This value reflects the maximum dark-adapted photochemical efficiency of photosystem II (PSII) reaction centers involved in photosynthesis and is an indirect measure of plant stress. The objective of this study was to examine Fv/Fm as a method for stock plant selection and for monitoring rooting progress of various cultivars. Fv/Fm varied significantly (P ≤ 0.05) among cultivars, initially and over time. However, there was significant overlap among some cultivars. The Fv/Fm decreased dramatically during cold storage, but usually returned to original levels after several weeks in the propagation beds. This appeared to be a reflection of the reduction of water stress as the cuttings formed roots. Initial stock plant Fv/Fm was not correlated (P ≤ 0.05) with rooting percentage, root number, root dry weight, or root length, indicating that Fv/Fm is not a reliable indicator of stock plant rooting potential. Visual assessment is just as reliable.

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Calen McKenzie, Ivette Guzman, Ciro Velasco-Cruz, and Paul W. Bosland

Chlorophylls and carotenoids are responsible for harnessing the photon energy ultimately used in the splitting of a water molecule in photosynthesis ( Buchanan, 2015 ). Two primary chlorophylls responsible for photosynthesis in plants—Chl a and

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B.M. Cregg, M.W. Duck, C.M. Rios, D.B. Rowe, and M.R. Koelling

We assessed variable chlorophyll fluorescence (Fv/Fm) and needle chlorophyll concentration of seedlings of Maccedonia fir (Abies borisii regis Mattfeld), subalpine fir [A. lasiocarpa (Hooker) Nuttall], Sakhalin fir [A. sachalinensis (Schmidt) Mast.], Siberian fir [A. sibirica (Lebed.)], and Veitch fir (A. veitchii Lindl.) grown under varying soil media pH. Soil media pH was modified using liquid flowable dolomitic limestone, resulting in five pH levels (3.4, 4.0, 5.4, 6.0, and 6.8). Increasing media pH significantly reduced Fv/Fm and needle chlorophyll concentration in all of the species tested. The effect of pH on photochemistry was due to depressed nutrient uptake of P, Mn, B, and Cu. Because photosynthetic quantum yield may be related to deficiencies of several elements affected by pH, Fv/Fm may serve as a criterion to select for improved pH tolerance. Among the species examined, A. veitchii and A. lasiocarpa were most tolerant of increased pH based on Fv/Fm and needle chlorophyll concentration.

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Mahalaxmi Veerasamy, Yali He, and Bingru Huang

Temperatures greater than the optimal growth temperature negatively affect plant growth and induce various physiological and metabolic changes, including premature leaf senescence. Leaf senescence is characterized by loss of chlorophyll and