Some aspects of the ecophysiology of flowering intensity of mango (Mangifera indica L.) cv. Nam Dok Mai in a semi-tropical monsoon Asian climate.
Pongsomboon W., Subhadrabandhu S., Stephenson R. A.
Author Affiliation: Horticultural Research Institute, Department of Agriculture, Bangkok 10900, Thailand.
Scientia Horticulturae 70 : 45-56
Abstract : During the dormant period in 1988-89, 4-year-old mango cv. Nam Dok Mai trees grown in an orchard at Kasetsart University (Kamphaengsaen Campus), Nakhon Pathom Province, Thailand, were studied. The changes and relationships between leaf xylem water potential (?x), relative water content (RWC), total nonstructural carbohydrates (TNC) in terminal shoots, and GA3- and ABA-like substances in shoot tips during November and December, and flowering were studied. Changes in ?x and RWC were from -0.31 MPa and 97% at the beginning of the dry period (mid-November) to -0.82 MPa and 93%, respectively, in mid December. There was a positive correlation between ?x and RWC. Low TNC levels were about 70-98 mg glucose equivalent/g DW at the beginning of the dormant period and thereafter increased to 110-120 mg glucose equivalent/g DW and finally declined to about 70 mg glucose equivalent/g DW prior to flowering. TNC values were poorly correlated negatively with RWC, but not correlated with ?x. GA3-like substances were high (1.5-1.7 µg equivalent/g FW) at the beginning of the dormant period, but declined by about 50% in late November prior to increasing slightly through to inflorescence emergence. The change in ABA-like substances was comparatively small during the dormant period. GA3-like substances were negatively correlated with RWC and ?x whereas ABA-like substances were not. Flowering intensity was negatively correlated with average RWC and average ?x, but was correlated with TNC. Flowering intensity was negatively correlated with GA3-like substances, but not with ABA-like substances.