turf quality in kentucky bluegrass under drought has been related to increases in antioxidant activities ( Fu and Huang, 2001 ; Xu et al., 2011a ). Proline, an amino acid, plays a highly beneficial role in plants when they are exposed to various stress
sterilized water to remove the culture media. Then, 5-mm-long rhizome apical segments were placed on MS media containing 0.2, 0.5, 1.0, or 2.0 mmol·L −1 of nonpolar amino acids (glycine, alanine, valine, leucine, isoleucine, proline, phenylalanine
seedlings under each treatment were selected and one healthy upper crown leaf on each representative seedling was selected for biochemical measurements. The chlorophyll content was measured according to the method of Li (2000) . The proline content was
( Heath and Packer, 1968 ). Free proline content was determined according to the method described by Bates et al. (1973) . Fully expanded leaves (≈0.2 g) were extracted with 5 mL of 3% (w/v) sulphosalicylic acid. For 2-mL extracts, 2 mL of 2.5% ninhydrin
small molecular organic compounds, including amino acids, organic acids, and soluble sugars ( Evers et al., 2010 ). Some important small molecular metabolites, such as proline, salicylic acid, and sucrose, are known to accumulate in large quantities
, exceeding the optimum for tomato growth (temperatures often rise to 30 to 40 °C and light intensity can reach 1000 to 2000 μmol·m −2 ·s −1 ). Plant antioxidant defenses also depend on aminated compounds such as proline (Pro) and polyamines (PAs), the
to cope with stresses ( Huang and Fry, 1999 ; Lee et al., 2008a , 2008b ; Shahba, 2010b ). Amino acids, especially proline, accumulate in larger amounts to cope with increasing stress in plants ( Lee et al., 2008b ). Proline accumulation is one of
water potential. In addition, the level of lipid peroxidation of cell membranes and amino acid contents such as proline increase ( Dong et al., 2012 ; Nogués et al., 2002 ; Sun et al., 2017 ; Wang et al., 2012 ). FOph management in cape gooseberry has
examine specifically whether the calcium ion is involved in coordination with physiological indices including antioxidant contents, chlorophyll, protein content, free proline and malondialdehyde (MDA), and/or the HSF transcriptional expression during high
peroxidation was evaluated by measuring MDA and H 2 O 2 contents as described in Liu et al. (2014) . Sucrose and proline contents were estimated using the methods of Wu et al. (2011) and Man et al. (2011) , respectively. All data were analyzed using the