RESULTS AND DISCUSSION
Chlorophyll and leaf NPK content
The potassium application resulted in a significant increase in chlorophyll of tomato leaves as compared to both
the control and plants treated with GA3 either alone or in combination. The chlorophyll increased to its
maximum (48.14 SPAD) with 8 mM potassium nitrate application. N content was maximum in treatment 8 mM
potassium nitrate (Table 1). The N content was not affected by application of GA3 alone or in combination. The
P content was not affected by application of GA3 either alone or in combination. The maximum K (2%) and P
(0.42 %) content was recorded with 8 mM potassium nitrate application, followed by 1.95(%) with 6 mM
potassium nitrate and 1.8 (%) with 10-8
mM GA3+8 mM potassium nitrate (Table 1). These results are in
agreement with previous investigation indicated by Zhang et al. 2002; Lin and Danfeng 2003. They found that
increasing in vegetative growth, net photosynthetic rate, NPK content and chlorophyll content were associated
with increasing of K levels. Potassium affects respiration, photosynthesis, leaf NPK content, chlorophyll
development, water content of leaves, carbon dioxide (CO2) assimilation and carbon movement (Sangakkara et
al,. 2000) Thus, it can be concluded that photosynthesis and, correspondingly, formation of carbohydrates such
as glucose, saccharose, etc. increased due to chlorophyll content in response to potassium treatments for tomato
compared with the untreated control.