Influence of Water Regimes and Potassium Chlorate on Floral Induction, Leaf Photosynthesis and Leaf Water Potential in Longan

This study verifies the influence of water regimes and potassium chlorate (KC1O3) on photosynthetic rate, flower emergence and media moisture content of longan trees. The trees were grown in 150 liters lysimeter tanks filled with fine sand. The experimental design was a 2x2 factorial in completely randomized design (CRD) with 2 factors; 1) two levels of water regimes (well-watered and water deficit) and 2) two levels of KClO3 at 10 and 0 g. The results revealed that the well-watered treatment produced faster days of terminal bud break than that of the water deficit treatment. The 10 g KClO3 treatment induced 91 % flower emergence at 35 days after commencing the treatment, while the 0 g KClO3 treatment had 82 % leaf flushing and had no flower emergence. Water deficit or KClO3 treatments reduced the net carbondioxide (CO2) exchange, transpiration and stomatal conductance rates. Moreover, the combination of well-watered and 0 g KClO3 treatments gave the greatest values of the parameters. The well-watered treatment had higher volumetric water content in the growing medium and leaf water potential than the water deficit treatment, while for the 10 g and 0 g KClO3 treatments had similar the media moisture content.