Table III.

In situ fluorescence characteristics of varieties IR72 and IR65600-42-5-2 (NPT) plants in LL, ML, and HL conditions (10%, 40%, and 100% of full sunlight, respectively)

Variety and Growth ConditionFv/FmqPΦ PSII
IR72
 LL0.805 ±  0.0020.884 ±  0.0160.707 ±  0.013
 ML0.765 ±  0.0030.607 ±  0.0470.424 ±  0.024
 HL0.752 ±  0.0050.461 ±  0.0250.255 ±  0.013
NPT
 LL0.803 ±  0.0020.923 ±  0.0220.711 ±  0.025
 ML0.773 ±  0.0020.714 ±  0.0250.468 ±  0.013
 HL0.736 ±  0.0030.519 ±  0.0150.268 ±  0.015 

Measurements were taken during mid-morning and midafternoon when incident irradiance was greatest (as dictated by the upright leaf posture). F v/F m was measured following a 10-min dark adaptation period. qP and quantum yield of PSII reaction centers (ΦPSII) were calculated as described in the text. Values represent means of measurements taken over a 2- to 3-d period ± se, n > 20.