The objective of this study was to find a rapid determination of the hot air stress in maize (Zea mays L.) leaves using a portable chlorophyll fluorescence imaging instrument. To assess the photosynthetic activity of maize leaves, an imaging analysis of the photochemical responses of maize was performed with chlorophyll fluorescence camera. The observed chlorophyll imaging photos were numerically transformed to the photochemical parameters on the basis of chlorophyll a fluorescence. Chlorophyll a fluorescence imaging (CFI) method showed that a rapid decrease in maximum fluorescence intensity (Fm) of leaf occurred under hot air stress. Although no change was observed in the maximum quantum yield (Fv/Fm) of the hot air stressed maize leaves, the other photochemical parameters such as maximum fluorescence intensity (Fm) and Maximum fluorescence value (Fp) were relatively lowered after hot air stress. In hot air stressed maize leaves, an increase was observed in the nonphotoquenching (NPQ) and decrease in the effective quantum yield of photochemical energy conversion in photosystem II (Φ PSII). Thus, NPQ and ΦPSII were available to be determined non-destructively in maize leaves under hot air stress. Our results clearly indicated that the hot air could be a source of stress in maize leaves. Thus, the CFI analysis along with its related parameters can be used as a rapid indicating technique for the determining hot air stress in plants.

MATERIALS AND METHODS
  Growth Condition of Plants
  Data Analysis
 RESULTS AND DISCUSSION
  Chlorophyll Fluorescence Imaging (CFI) Analysis
  Maximum Quantum Yield (Fv/Fm) and Other Parameters
  Effective Quantum Yield of Photochemical EnergyConversion (ΦPS II)
  Non-photochemical Quenching (NPQ)
  Fluorescence Decrease Ratio (Rfd)
 CONCLUSIONS
 REFERENCES

• Jong Yong Park(Biological Research Part, Hanearl Science, Department of Plant Life and Environmental Science, Hankyong National University)
• Sung Young Yoo(Institute of Ecological Phytochemistry, Hankyong National University, Junang-ro 327, Anseong, Gyeonggi-do, 17579, Republic of Korea)
• Hong Gyu Kang(Department of Plant Life and Environmental Science, Hankyong National University, Junang-ro 327, Anseong, Gyeonggi-do, 17579, Republic of Korea)
• Tae Wan Kim(Department of Plant Life and Environmental Science, Hankyong National University, Institute of Ecological Phytochemistry, Hankyong National University, Junang-ro 327, Anseong, Gyeonggi-do, 17579, Republic of Korea) Corresponding author