Twonewlybredhybridricecombinations,superhigh-yieldingLiangyoupeijiu(Pei'ai64S×9311)andPei'ai64S/E32(Pei'ai64S×E32)wereusedtoinvestigatethephotosyntheticcharacteristicsunderhightemperatureincomparisonwithhybridriceShangyou63.Hightemperaturecausedadecreasedphotosyntheticefficiencyandaggravatedphotoinhibition.TheoptimumtemperatureforphotosyntheticelectrontransportationandphotosyntheticCO2fixationwereabout28℃and35-40℃respectively.Linearelectrontransportationismoresensitivetohightemperaturethanthephotochemicalprocess.Themechanismofhightemperatureadaptationwaspossiblyasfollows:superhigh-yieldingricehasquicklyincreasingcarotenoid,whichactedasamorefavorableantioxidantsystemtoreducetheactiveoxygenproductionandavoiddamagetothephotosynthesissystem;superhigh-yieldingricehasahigherefficiencyofxanthophyllscycletodissipateexcessheatenergy;superhigh-yieldingricehasamorestablephotosyntheticfunction,higherphotosyntheticefficiencyandmoreheatstableproteincontent.
