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Indian Journal of Experimental Biology (IJEB) >
IJEB Vol.49 [2011] >
IJEB Vol.49(01) [January 2011] >
| Title: | Relationship between xanthophyll cycle and non-photochemical quenching in rice (Oryza sativa L.) plants in response to light stress |
| Authors: | Vaz, Janet
Sharma, Prabhat K |
| Keywords: | Energy dissipation
Light stress
Non-photochemical quenching
Rice
Xanthophyll cycle |
| Issue Date: | Jan-2011 |
| Publisher: | NISCAIR-CSIR, India |
| Abstract: | Thirty days old rice plants grown under low and moderate light
conditions were
transferred to full sunlight to observe the extent of photoinhibitory damage
and protective mechanism, and the relationship between xanthophyll cycle and
non-photochemical quenching (qN) under changing light environment. Control
plants (low, moderate and sun grown) exhibited similar Fv/Fm ratio, indicating
similar photosynthetic efficiency prior to light stress. On exposure to the
high light treatment, low light grown plants exhibited faster and higher degree
of photoinhibition compared to moderate and high light grown plants. Moderate
and high light grown plants showed relatively less photoinhibition and also
showed higher qN, indicating better capacity of energy dissipation. Increase in
qN in moderate light and sun grown plants was accompanied by conversion of
violaxanthin (V) to antheraxanthin (A) and zeaxanthin (Z) indicating operation
of Z-dependent thermal dissipation. Rice plants fed with ascorbate (AsA), a
stimulator of the de-epoxidation state of V to Z, showed higher Fv/Fm ratio and
qN than the plants fed with dithiothreitol (DTT) an inhibitor of xanthophyll
cycle. This indicated that an increased amount of energy reached PS II reaction
centre, due to absence of A and Z formation, thereby causing greater damage to
photosynthesis in DTT fed rice plants. The present data confirmed the
relationship between qN and Z in dissipating the excess light energy, thereby
protecting plants against photodamage. |
| Page(s): | 60-67 |
| CC License: |  CC Attribution-Noncommercial-No Derivative Works 2.5 India |
| ISSN: | 0975-1009 (Online); 0019-5189 (Print) |
| Source: | IJEB Vol.49(01) [January 2011]
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