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Mubarak S. Khalafalla and David A. Palzkill

Total nonstructural carbohydrates (TNC), starch, total soluble sugars, sucrose, and proline concentrations were monitored for 18 months in leaf tissue of two jojoba [Simmondsia chinensis (Link) Schneider] clones that differ in frost susceptibility. Seasonal changes in TNC and starch concentrations, with maxima in the winter and minima in summer, were significant. Sugar levels decreased from fall to spring and increased during early summer. The more frost-resistant clone (C-1) had significantly higher sugar concentrations during most of the study than the less frost-resistant clone (C-2). Proline concentrations largely followed the trends found for TNC. The C-1 clone had the higher levels of proline, except when C-2 was frost-injured. Growth trends were similiar between C-1 and C-2, with a major growth flush from March to May. Relatively high levels of starch preceded growth flushes.

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A. C. Purvis and G. Yelenosky

Abstract

Four-year-old ‘Marsh’ grapefruit (Citrus paradisi Macf.) trees on trifoliate orange [Poncirus trifoliata (L.) Raf.] rootstock were temperature acclimated to 5°C in controlled environment facilities with approximately 400 μeinsteins m−2s−1 PAR. Total soluble carbohydrates and proline increased in both leaves and fruit flavedo as temperatures were progressively decreased. Maximum accumulation of carbohydrates occurred in leaves and flavedo at 10° ambient air. Both sucrose and reducing sugars increased in leaves at all acclimating temperatures, but only reducing sugars increased in the flavedo at temperatures below 15°. The concentration of proline was the greatest in the leaves and flavedo at 5°. Both total soluble carbohydrates and proline decreased during temperature deacclimation at 25°.

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Yehoshua Saranga, David Rhodes, and Jules Janick

Tolerance to partial desiccation and amino acid composition of celery (Apium graveolens L. cv. SB 12) somatic embryos were investigated under various culture durations and with exogenous application of 1 μm ABA, proline, and/or γ -aminobutyrate (GABA). ABA consistently increased tolerance to partial desiccation and elevated proline and GABA content of embryos. The changes in tolerance to partial desiccation associated with changes in culture duration (optimum 9 to 10 days) correlated with embryo proline content. Exogenous proline increased embryo proline content and tolerance to partial desiccation. Exogenous GABA increased embryo GABA content and tolerance to partial desiccation only when applied in combination with proline. Chemical name used: abscisic acid (ABA).

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Masoud Arghavani, Mohsen Kafi, Mesbah Babalar, Roohangiz Naderi, Md. Anamul Hoque, and Yoshiyoki Murata

Swartz), Sakr (2009) showed that TE application increased turf coverage percentage, lawn density, fresh and dry weight of underground parts, leaf Chl, carotenoides, carbohydrates, and K + content and decreased leaves’ proline, Na + , and Cl

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Majken Pagter, Karen K. Petersen, Fulai Liu, and Christian R. Jensen

proteins including dehydrins and other late-embryogenesis–abundant (LEA) proteins, glycine betaine, and proline ( Arora et al., 1992 ; Lennartsson and Ögren, 2002 ; Rinne et al., 1998 ; Xin and Browse, 2000 ). ABA, a well-known stress-inducible plant

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Augusto Ramírez-Godoy, María del Pilar Vera-Hoyos, Natalia Jiménez-Beltrán, and Hermann Restrepo-Diaz

gaseous exchange properties, chlorophylls, leaf temperature, and growth have been useful in identifying plant tolerance against pests ( Mitchell et al., 2016 ). In addition, proline and malondialdehyde (MDA) synthesis plays an important role to

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Jaejoon Kim and David J. Wolyn

breeding program. Compounds with cryoprotective properties such as proline, glucose, sucrose, and fructans may contribute to freezing tolerance of the overwintering asparagus crown. Proline is known to stabilize protein synthesis, increase water

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Thanaa M. Ezz, Mark A. Ritenour, and Jeffrey K. Brecht

Heat treatments and exposure to elevated CO2 are known to reduce the incidence of chilling injury on grapefruit. In the current study, `Marsh' grapefruit (Citrus paradisi Macf.) were harvested on 17 Jan. or 22 Mar. 1996 and exposed to hot water (HW) dips (48 °C for 120 minutes) or exposed to controlled atmosphere (CA) of 10% or 16% CO2 during the first 3 weeks of an 8-week cold storage period (4.5 °C) to test their effects on the development of peel pitting (i.e., chilling injury) and proline and other compositional changes of the peel and juice. All HW and CA treatments from both harvests greatly reduced the development of peel pitting compared to the control. These treatments were also associated with lower average proline levels in the flavedo during storage. This suggests that HW and elevated CO2 may reduce chilling-induced peel pitting by facilitating proline metabolism in grapefruit flavedo tissue. HW and CA treatments resulted in higher peel total soluble and nonreducing sugar levels, but effects on peel reducing sugar and free amino acid concentrations were not consistent. In the juice, HW reduced titratable acidity (TA) concentrations while CA tended to increase both TA and ascorbic acid concentrations. Compared to the control, CA resulted in a slight decrease in total soluble solids during storage, while the effect of HW was inconsistent.

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C.P. Sharma and Sandhya Singh

When grown in refined sand with one-twentieth normal K supply, cauliflower (Brassica oleracea L. var. botrytis L. cv. Pusi) had lower dry matter and tissue concentration of K than the controls and developed visible symptoms characteristic of K deficiency. In K-deficient plants, the specific leaf weight, diffusive resistance, and proline concentration in leaves were significantly higher and relative water content (RWC), leaf water otential (ψ), stomatal aperture, stomatal density, and transpiration rate were significantly lower than in control plants. When K-deficient plants were supplied additional Na to the extent K was deficient, Na concentration in the plants increased and the plants recovered from the K deficiency effect on free proline concentration, RWC, leaf water potential, stomatal aperture, stomatal density, specific leaf weight, diffusive resistance, and transpiration.

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Shahzad M.A. Basra and Carol J. Lovatt

sugars by the anthrone method ( Yemm and Willis, 1954 ), soluble protein ( Bradford, 1976 ), the free amino acids proline ( Chinard, 1952 ) and arginine by the method of Sakaguchi as described in van Pilsum et al. (1956) , total antioxidants using the