EFFECTS OF NITROGEN CONCENTRATIONS ON PHOTOSYNTHESIS CHANGE OF LONGAN IN LYSIMETER

The experiment was conducted in order to determine the effects of nitrogen concentrations on leaf photosynthesis of longan on two-year old grafted ‘Do’ longan trees.
The experiment was conducted at Lampang Agricultural Research and Training Center, Lampang during June 2003 – August 2004. The experimental design used was a CRD with five treatments, i.e. 0, 56, 112, 224 and 448 mg N L^-1 of nutrient solution modified from Hoagland and Arnon.
The results showed that the 448, 224, 112 and 56 mg N L^-1 treatments from August 2003 to June 2004 gave higher efficiency of photosystem II (Fv/Fm) than the 0 mg N L-1 treatment (control). The 448 mg N L^-1 treatment had the highest change of chlorophyll content in leaf but the 0 mg N L^-1 treatment showed the lowest content.
In addition, all treatments showed no difference in the change of transpiration rate or stomata conductance rate.
The 448 mg N L^-1 treatment possessed the highest net CO₂ assimilation rate change during August – September 2003 and June 2004.

International Workshop on Tropical and Subtropical Fruits

C. Sritontip, Y. Khaosumain, S. Changjeraja

photosystem II (Fv/Fm), chlorophyll content, transpiration rate, stomata, conductance rate, CO₂ assimilation

https://doi.org/10.17660/ActaHortic.2008.787.27