Water Dynamics in Mango (Mangifera indica L.) Fruit during the Young and Mature Fruit Seasons as Measured by the Stem Heat Balance Method

Abstract

Water flows in the stem and peduncle of mango fruit were monitored, and the surface transpiration from the fruit was measured during the fruit-growing season. The stem heat balance method was used on the peduncle to monitor the inward water flow during the nighttime, and the reverse water flow from the fruit during the daytime when the stem transpiration water flow increased. This diurnal fluctuation pattern in the water flow was more evident in mature fruit than in young fruit. In mature fruit, the daily water loss due to the reverse flow was estimated to be 3% of the fruit weight. The reverse flow water loss and transpired water loss were compensated for by nocturnal inward water flow, through the peduncle, of 30 g over 15 h. These results were well supported by measurements of fruit dimensions, which indicated a circadian rhythm of contraction and expansion. The reverse flow amounted to 80% of the water loss from the daytime contraction of the fruit, a much greater proportion than the fruit surface transpiration.

Water relations of Calycanthus flowers: Hydraulic conductance, capacitance, and embolism resistance

“…If the diurnal rate of change in abiotic conditions and Ψ stem is sufficiently fast, then maintaining a high hydraulic capacitance may be an effective strategy of preventing turgor loss, thus compensating for flowers having a high Ψ TLP . In flowers or fruits with long lifespans, water stored in these structures may even flow back to the stem, such as has been shown for developing mango fruits (Higuchi & Sakuratani, ).…”

Hydraulic conductance and the maintenance of water balance in flowers

“…hydraulic capacitance; Chapotin et al ) that could be depleted throughout anthesis. Regardless of whether flowers have high hydraulic capacitance or rely on water delivered by the phloem, maintaining a higher water status in flowers could result in water being drawn back into the stem during the day, as has been shown to occur in fleshy fruits (Higuchi and Sakuratani ). The supposed dichotomy between xylem‐hydration and phloem‐hydration in flowers is likely not a dichotomy after all but rather a spectrum between more or less contributions from the phloem.…”

An external heat pulse method for measurement of sap flow through fruit pedicels, leaf petioles and other small‐diameter stems

“…This latter example is a major quality factor influencing fruit storability, processing, nutritional value and consumer perception of fruit flavour and texture. However, despite their relevance, published accounts of direct in vivo measurements of sap flow to or from developing fruit are rare (Higuchi & Sakuratani 2006; Windt 2007). The reason is probably that there are currently no methods suitable for routine measurement of the small flows involved.…”

“…Coners & Leuschner (2002) successfully measured flows through tree fine roots 3–4 mm in diameter, but flows less than 2 g h −1 required an empirical correction. Higuchi & Sakuratani (2005, 2006) reduced the size of their gauge, and successfully measured minimum sap flows of approximately 1 g h −1 through mango inflorescences and fruit pedicels. However, based on transpiration measurements, maximum sap flows through developing kiwifruit pedicels and many other small‐diameter stems are often less than 0.5 g h −1 , and if sap flow reversal occurs, the transition through zero is often the period of most interest.…”