Studies On Differences Of Photosynthetic Efficiency Of Flag Leaf Between Hybrid Rice Hyou129 And Shanyou63 And The Mechanism Of Photosynthetic Function Declination

In recent years, per unit area yield of rice was always at a standstill. Improving the photosynthetic efficiency of rice leaf was a important way to increase yield of rice ulteriorly. Hybrid rice LLyoul29 and shanyou63 had notable difference in their yield and photosynthetic efficiency. Differences on photosynthetic traits during the life span of flag leaves were compared between Ilyoul29 and Shanyou63 at leaves and chloroplasts levels, and hope to find some restrictive factors which hinder further improvement of photosynthetic efficiency of leaves and yield of rice. Simultaneously, explored the mechanism of photosynthetic function declination of rice leaves. The results suggested that main factors which effected the yield of lIyoul29 over that of Shanyou63 were following: The IAPS(instantaneous apparent photosynthesis) of llyou 129 flag leaves was higher than that of Shanyou63 ,the APD(active photosynthetic duration) was longer , and the LSC(leaf source capacity)was larger. Difference of TAPS of flag leaves between Ilyou 129 and Shanyou63 was mainly influenced by difference of stomatal conductance (Gs) and mesophyll conductance ((3m). Moreover, difference of capacity of absorption light of leaves might be a reason that caused difference of lAPS of leaves. In natural environment, there was remarkable photoinhibition phenomenon in Ilyoul29 and Shanyou63. IIyoul29 was better in enduring photoinhibition than Shanyou63. Under strong light, the decline of LAPS of IIyoul29 was smaller, and CO2 assimilation capacity per day is bigger, so it was an important reason that the LSC of IIyoul29 was bigger than that of Shanyou63. Xanthophyll cycle was a important mechanism that defended 3 玎i~o鄆hdition 慳 ace, Eymal29 ~ bdtcr 1. endwing pb.toinhlbitioa, haause Hy.i 129 has bier Xm~1utyli cycle pool(V+A+Z) and higher ca~ucdy fra.uforutng Viokxanthin to Zaxatlhin md Aadheraxarlhin wiler slmag Iigh~A+1扸+A+Z). Dw~g the ap~ e of lag leaves 韆 llyou 129 and Shaayo.~3, i~iaI actwity of RnBFCasc and Gui ~e minaxkab~?rdat.d to lAPS, and their 鑓limbon iute 慳uc ruaadr~y ka~ than ~f of some iniber pI~os~udaetk lurametct~ ~ilclL ~re lAPS, Ga, aclivity of arbou~ic an1~dmsc(CA), Fv/Fmn, ~鄌tochetuiczI qmaeadai.gI~). ibm wlmtc ~ctron tinnier rate etc. T1~efo,, the ~d鋟u of (3m uid initial a~vity of RnBftaw night 慶c tram reason that caused lAPS to dcacail dining die a.ing cwse of flag lcavcs. The declination rate of FvIFtn~ qP~ die clectmn tmmI~ rate ~. were remarkably sIov~r than that of some ~in,uiie~抯 of carbom assimdation. The fonner parameters ~ related to pm鄊ing aa~nt鋋tion po~u, and the later parameters were related to ~iili~ of the energy dial ~s absorbed aml transferred on the photnuynthetic Obviously, there s an un1ulaa~ Carbon uzd~uisnccd pbc.inunoui?in our l~wutixy. Uccause of the 搖nl~am~cd phenomezien? the comae of leaf ~ce~e and 1IioS~抯y~~betic fwietiout declitutiou ~s quickes~d. The 間ec of 憕gbl-cd~on i~mIancc?was n~re smo.as in ~an~uG3 tlun duE in ilyonl29, dure&re, die ~oeoiny~he& finietion dechxutigm of ~m~3 was ~Im, mmd die hi span and API) of were The flw,ma~ spectra H 77k low tcnya~a1ure suggested that the distribution dcxn~atim uiet~y ~s nure lulamx銲e between PSI mmd PSI! in tIyoul29 dua tiut in Shanyou6.3. Dining die dc~el~~nmt course of leaves, the of light4uzwsdng p piemt-putein ~ompiex of PSI (LHCI) might be faster tha...