plants are exposed to abiotic stress conditions ( Bowler et al., 1992 ; Mittler, 2002 ; Noctor and Foyer, 1998 ). Higher levels of antioxidant enzymes are associated with drought tolerance in some turfgrass species ( DaCosta and Huang, 2007 ). Proline
pomegranate orchards in Saveh, the second pomegranate-producing region in Iran, and had a serious adverse economic impact on growers. Some biochemical changes such as increasing the amounts of total carbohydrates ( Morin et al., 2007 ), proline ( Lalk and
The proline contents of anthers, pollen, pistils, and leaves were examined in several tomato (Lycopersicon esculentum Mill.) cultivars under different temperature conditions. The proline content in anthers increased with advancing development of floral buds to a maximum at anthesis. The pistil contained less proline than the anthers and did not accumulate proline with advancement of floral bud development in most cultivars. High temperature reduced proline content in anthers regardless of the stages of floral bud development. It also tended to reduce proline content in pistils of later floral bud stage. The proline content of the leaves was lower than that of anthers or pistils; however, high temperature increased the proline level in the leaves. Pollen collected from the hot-season planting contained less proline than that collected from the cool-season planting. The addition of proline to germination medium enhanced pollen germination rate and increased pollen resistance to heat. These results suggest that the low proline accumulation in anthers and pollen at high temperature may be the result of the high accumulation in the leaves. Also, high proline content in anthers may be necessary to confer heat resistance to pollen germinating at high temperatures.
.11.1.6), POD (EC 188.8.131.52), and APX (EC 184.108.40.206) ( Hossain et al., 2010 ). The other is the nonenzymatic antioxidants, such as proline, reduced GSH, AsA, and phenolics ( Blokhina et al., 2003 ; Szabados and Savouré, 2010 ; Tsantili et al., 2010 ). It is
roots by contributing to the accumulation of osmoticants, including proline, free amino acids, and sugars ( Kubikova et al., 2001 ; Yooyongwech et al., 2013 ). AM fungi can also change plant root system architectures in favor of increased water
The purpose of this study was to evaluate seasonal changes in the free proline content of citrus roots, leaves, fruit peel, and juice in response to low-temperature and water stress. Nonirrigated trees generally had higher proline in all tissues than did irrigated trees except immediately after a freeze. At this time, nonirrigated trees were less water-stressed because of the greater amount of freeze-induced defoliation that nonirrigated trees had sustained. Using data from an entire year, proline concentration was not correlated with water stress of leaves or fruit. This lack of correlation probably was due to the interacting effects of water stress and low temperature on proline accumulation. Leaves accumulated proline in response to stress before roots and fruit. These data support the idea that the free proline increases first in the leaves in response to stress and subsequently is transported to other tree tissues. Even though proline content in the juice increased with fruit maturity, proline may not be a good indicator of juice quality since it did not always correspond with Brix:acid ratio and fruit in the most exposed canopy positions tended to have the highest proline content.
Mature lemon trees (Citrus limon (L.) Burm. f.) were subjected to a long period of severe water stress. Free proline accumulated in leaves of water stressed trees, and returned to normal soon after irrigation was resumed. There was a linear relationship between free proline contents and noon xylem pressure potential.
Peel samples of ‘Marsh’ grapefruit (Citrus paradisi Macf.) from 2 separate chilling injury (CI) experiments conducted during the 1979–80 season were analyzed for proline. Proline levels were highest in the peel of grapefruit after the seasonal night temperatures reached their minimum and levels declined after night temperatures increased in the spring. The greatest resistance of grapefruit peel to CI during postharvest cold storage coincided with high proline concentrations. Peels of unexposed interior canopy fruit had higher proline contents and were also more resistant to CI than peels of exposed exterior canopy fruit. Proline accumulation may be a consequence of an environmental stress rather than a cause of hardening to the stress or a mechanism of resistance.
)] × 100. At harvest, roots were collected, washed with tap water, dried with towel paper, and weighed. Next, lateral branches were counted in each root. After this, roots were dried at 70 °C until constant weight. Proline content was estimated
chlorophyll = [20.2 (A 645 ) + 8.02 (A 663 )] × Vol × (0.001) × W where A is the absorbance, Vol is the total volume of filtrate, and W is the weight of the leaf material. The proline content was determined with the sulfosalicylic acid method ( Bates et al