Effect of Initiation Timing of Drought Stress on Carbohydrate Content and Vegetative Growth in Japanese Apricot (Prunus mume Sieb. et Zucc.) ‘Nanko’

Abstract

The effects of initiation timing of drought stress on the carbohydrate content and growth of Japanese apricot (Prunus mume Sieb. et Zucc.) 'Nanko' tree were investigated. Three-year-old trees were subjected to drought stress for three months in May ('Spring') and August ('Summer'), respectively. Irrigation was started immediately after drought stress treatment had finished. The starch concentration in the roots of stressed trees increased in both 'Spring' and 'Summer' two months after starting drought stress treatment and rapidly decreased just after starting irrigation in 'Spring'; however, it still temporarily increased in 'Summer'. These different results were attributed to seasonal changes in the carbohydrate demand. The dry matter weight of each tree organ in February of the following year was suppressed by drought stress, particularly in 'Spring'. This result indicates that, if a tree suffers drought stress in spring, vegetative growth is suppressed more seriously than in summer and tree growth, declined by suffering from severe and long-term drought stress, will hardly recover even the tree is reirrigated. The total starch in all organs of the drought-stressed trees in February of the following year was significantly less than that in well-irrigated trees. These results indicate that severe drought stress for three months inhibits not only current tree growth but also the accumulation of carbohydrates that is necessary for the following year's growth. Hence, irrigation to avoid a fatal growth decline due to severe drought stress is needed during the current growth stage, especially in the early growth stage in spring.

Organ-dependent seasonal dynamism of three forms of carbohydrates in Japanese apricot

“…6). Our previous study showed that physiological fruit drop in the beginning of May occurs as a result of severe competition between shoot and fruits for currently synthesized carbohydrates (Tsuchida et al, 2011a) and that drought stress around May strongly inhibits vegetative growth (Tsuchida et al, 2011b). These findings confirm that growth of new organs above ground in May of the following year depends on currently assimilated rather than reserve carbohydrates.…”

Effect of High Temperature and Drought Stress on Carbohydrate Translocation in Japanese Apricot ‘Nanko’ Trees

“…Previous reports clarified that water stress reduces the 13 C translocation rate in the shoots of pear trees (Teng et al, 1999) and the satsuma mandarin (Yakushiji and Morinaga, 1998), and that drought stress inhibits the accumulation of carbohydrates in the branches and roots of the Japanese apricot tree (Tsuchida et al, 2011). In the present experiment, the 13 C concentration in the twigs, fine roots, middle roots, and large roots of the drought-stressed trees at 34°C was low (Fig.…”

“…This result can be attributed to the short period (2 months) of stress application. Tsuchida et al (2011) demonstrated that the dry weight of Japanese apricot trees declined over approximately a 3-month period of drought stress; therefore, a period of drought stress longer than 2 months is likely to cause visible tree growth inhibition. However, in this investigation, root 6.…”

“…Tsuchida et al (2011) also demonstrated that drought stress inhibits growth and carbohydrate accumulation in Japanese apricot trees. These results prove that the sugar translocation rate limits the growth rate (Hewitt and Curtis, 1948).…”

Recent Advances in Research on Japanese Pear Rootstocks

“…showed drought stress damaged not only shoot and fruit growth but also reduced reserve starch in the tree that will be used for the resumption of the next spring (Tsuchida et al, 2011). In Japanese pear, drought tolerance is also one of the most important characters for productivity of fruit.…”