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[Ｏｂｊｅｃｔｉｖｅｓ] Ｔｈｅ ｓｔｕｄｙ ａｉｍｅｄ ｔｏ ｅｘｐｌｏｒｅ ｔｈｅ ｅｆｆｅｃｔ ｏｆ ｆｏｌｉａｒ ｓｐｒａｙｉｎｇ Ｎ-ａｃｅｔｙｌ-Ｌ-ｃｙｓｔｅｉｎｅ ( ＮＡＣ) ｏｎ ｔｈｅ ｒｅｃｏｖｅｒｙ ｏｆ ｍａｃｈｉｎｅ-ｔｒａｎｓｐｌａｎｔｅｄ ｒｉｃｅ. [Ｍｅｔｈｏｄｓ]Ｔｈｅ ｃｏｎｖｅｎｔｉｏｎａｌ ｊａｐｏｎｉｃａ ｒｉｃｅ'Ｎｉｎｇｊｉｎｇ ７'ｗａｓ ｕｓｅｄ ａｓ ｔｈｅ ｅｘｐｅｒｉｍｅｎｔａｌ ｖａｒｉｅｔｙ ａｎｄ ｓｐｒａｙｅｄ ｔｏ ｓｅｅｄｌｉｎｇ ｌｅａｖｅｓ ｗｉｔｈ ｄｉｆｆｅｒｅｎｔ ｃｏｎｃｅｎｔｒａｔｉｏｎｓ ｏｆ ＮＡＣ ｆｏｒ ２ ｔｉｍｅｓ ａｔ ２ ｄａｙｓ ｂｅｆｏｒｅ ｔｒａｎｓｐｌａｎｔｉｎｇ. Ａｎｄ ４ ｔｒｅａｔｍｅｎｔｓ ｗｅｒｅ ｓｅｔ:ｓｐｒａｙｉｎｇ ｗａｔｅｒ( ＣＫ); ｓｐｒａｙｉｎｇ ２０ μｍｏｌ􀅰Ｌ-１ ＮＡＣ( Ｆ-ＮＡＣ２０ ); ｓｐｒａｙｉｎｇ ２００ μｍｏｌ􀅰Ｌ-１ ＮＡＣ( Ｆ-ＮＡＣ２００ ); ｓｐｒａｙｉｎｇ ２ ０００ μｍｏｌ􀅰Ｌ-１ ＮＡＣ (Ｆ-ＮＡＣ２０００ ). Ｔｈｅｎ ｔｈｅ ｔｉｌｌｅｒｓ ｇｒｏｗｔｈ, ｍｏｒｐｈｏｌｏｇｉｃａｌ ｉｎｄｅｘ( ｐｌａｎｔ ｈｅｉｇｈｔ, ｓｔｅｍ ｂａｓｅ ｗｉｄｔｈ, ｒｏｏｔ ｍｏｒｐｈｏｌｏｇｙ ｉｎｄｅｘ), ｃｈｌｏｒｏｐｈｙｌｌ ｃｏｎｔｅｎｔ, ａｎｔｉｏｘｉｄａｎｔ ｓｙｓｔｅｍ(ＳＯＤ, ＰＯＤ, ＣＡＴ ａｃｔｉｖｉｔｉｅｓ), ＡｓＡ-ＧＳＨ ｐｏｏｌ( ＡＰＸ, ＧＲ ａｃｔｉｖｉｔｉｅｓ ａｎｄ ＡｓＡ, ＧＳＨ ｃｏｎｔｅｎｔｓ) ａｎｄ ＭＤＡ, Ｈ２Ｏ２ ｃｏｎｔｅｎｔｓ ｗｅｒｅ ｉｎｖｅｓｔｉｇａｔｅｄ. [Ｒｅｓｕｌｔｓ]Ｔｈｅ ｒｅｓｕｌｔｓ ｓｈｏｗｅｄ ｔｈａｔ ＮＡＣ ｃｏｕｌｄ ｒｅｄｕｃｅ Ｈ２Ｏ２ ｃｏｎｔｅｎｔ ｔｈｒｏｕｇｈ ｓｉｇｎｉｆｉｃａｎｔｌｙ ｉｎｃｒｅａｓｉｎｇ ＧＲ ａｃｔｉｖｉｔｙ ａｎｄ ｐｒｏｍｏｔｉｎｇ ｔｈｅ ａｃｃｕｍｕｌａｔｉｏｎ ｏｆ ＧＳＨ ｗｈｉｃｈ ａｌｌｅｖｉａｔｅｄ ｔｈｅ ｏｘｉｄａｔｉｖｅ ｄａｍａｇｅ, ｍａｉｎｔａｉｎｅｄ ｃｅｌｌ ｓｔａｂｉｌｉｔｙ, ｒｅｄｕｃｅｄ ＭＤＡ ｃｏｎｔｅｎｔ, ｐｒｏｔｅｃｔｅｄ ｐｈｏｔｏｓｙｎｔｈｅｔｉｃ ｏｒｇａｎｓ, ｒｅｄｕｃｅｄ ｃｈｌｏｒｏｐｈｙｌｌ ｄｅｇｒａｄａｔｉｏｎ, ａｎｄ ｓｉｇｎｉｆｉｃａｎｔｌｙ ｐｒｏｍｏｔｅｄ ｒｏｏｔ ｇｒｏｗｔｈ ａｎｄ ｅｌｏｎｇａｔｉｏｎ, ａｎｄ ｓｉｇｎｉｆｉｃａｎｔｌｙ ｉｎｃｒｅａｓｅｄ ｔｈｅ ｎｕｍｂｅｒ ｏｆ ｐａｎｉｃｌｅｓ ａｔ ｍａｔｕｒｉｔｙ. Ａｔ ２ ｄ ａｆｔｅｒ ｔｒａｎｓｐｌａｎｔｉｎｇ, ｃｏｍｐａｒｅｄ ｗｉｔｈ ＣＫ, Ｆ-ＮＡＣ２０００ ｉｎｃｒｅａｓｅｄ ＧＲ ａｃｔｉｖｉｔｙ ｂｙ ６.４％, ＧＳＨ ｃｏｎｔｅｎｔ ｂｙ ９２.２％, ｄｅｃｒｅａｓｅｄ Ｈ２Ｏ２ ｃｏｎｔｅｎｔ ｂｙ ２５.７％, ａｎｄ ＭＤＡ ｃｏｎｔｅｎｔ ｂｙ ２６.３％, ｗｈｉｃｈ ｒｅｄｕｃｅｄ ｐｈｏｔｏｓｙｎ- ｔｈｅｔｉｃ ｐｉｇｍｅｎｔ ｄｅｇｒａｄａｔｉｏｎ ａｎｄ ｉｎｃｒｅａｓｅｄ ｃｈｌｏｒｏｐｈｙｌｌ ｃｏｎｔｅｎｔ ｂｙ １９.３％, ｉｎｃｒｅａｓｅｄ ｃａｒｏｔｅｎｏｉｄ ｃｏｎｔｅｎｔ ｂｙ ３６.６％, ａｎｄ ｔｈｅ ｎｕｍｂｅｒ ｏｆ ｒｏｏｔ ｔｉｐｓ ｉｎｃｒｅａｓｅｄ １６４.７％, ｒｏｏｔ ｌｅｎｇｔｈ ｉｎｃｒｅａｓｅｄ １０１.０％, ｒｏｏｔ ｄｉａｍｅｔｅｒ ｉｎｃｒｅａｓｅｄ ２６.８％. Ｔｈｅ ｇｒｏｗｔｈ ｏｆ ｔｈｅ ｓｅｅｄｌｉｎｇｓ ａｆｔｅｒ ｔｒａｎｓ- ｐｌａｎｔｉｎｇ ｗａｓ ｉｍｐｒｏｖｅｄ. Ａｔ ７ ｄ ａｆｔｅｒ ｔｒａｎｓｐｌａｎｔｉｎｇ, ｔｈｅ ｎｕｍｂｅｒ ｏｆ ｔｉｌｌｅｒｓ ｉｎｃｒｅａｓｅｄ ２.３％ ｃｏｍｐａｒｅｄ ｗｉｔｈ ＣＫ, ａｎｄ ｔｈｅ ｎｕｍｂｅｒ ｏｆ ｐａｎｉ- ｃｌｅｓ ｐｅｒ ｐｌａｎｔ ｗａｓ ０.４ ｍｏｒｅ ｔｈａｎ ｔｈａｔ ｏｆ ＣＫ. [Ｃｏｎｃｌｕｓｉｏｎｓ]Ｆｏｌｉａｒ ａｐｐｌｉｃａｔｉｏｎ ｏｆ ＮＡＣ ｃａｎ ａｌｌｅｖｉａｔｅ ｔｈｅ ｎｅｇａｔｉｖｅ ｅｆｆｅｃｔｓ ｏｆ ｔｒａｎｓｐｌａｎｔ ｓｈｏｃｋ ｏｎ ｓｅｅｄｌｉｎｇｓ, ｓｈｏｒｔｅｎ ｔｈｅ ｒｅｃｏｖｅｒｙ ｓｔａｇｅ, ａｎｄ ｐｒｏｍｏｔｅ ｔｈｅ ｇｒｏｗｔｈ ｏｆ ｔｉｌｌｅｒｉｎｇ ａｆｔｅｒ ｔｒａｎｓｐｌａｎｔｉｎｇ, ｏｆ ｗｈｉｃｈ ２ ０００ μｍｏｌ􀅰Ｌ-１ ＮＡＣ ｉｓ ｔｈｅ ｂｅｓｔ. [ABSTRACT FROM AUTHOR]

[Objectives] The study aimed to explore the remedial effect of foliar spraying astaxanthin(ASTA)on submerged rice at tillering stage after de-submergence.[Methods] The rice variety ‘Ningjing 7’ as experimental material was planted in pot,and five treatments were set up at tillering stage:normal moisture management(indicated by CT);submergence stress+spraying water(CK);submergence stress+spraying 0.4 mmol·L-1 ASTA(ASTA-0.4);submergence stress+spraying 0.8 mmol·L-1 ASTA(ASTA-0.8);submergence stress+spraying 1.6 mmol·L-1 ASTA(ASTA-1.6). The leaves of rice were sampled at 0,1,2,3,5,7 days after spraying ASTA,and analyzed on the effect on the photosynthetic pigment content,the activities of antioxidant enzymes(SOD,CAT,POD,APX,GR),membrane lipid peroxidation(MDA)content,hydrogen peroxide(H2O2)content and soluble protein content. The leaves of rice were sampled at 0,3,6,9 days after spraying ASTA,and analyzed on the effect on the dry weight,plant height and total soluble sugar content. The yield and its components were measured by collecting representational three-pot rice at maturity.[Results] The results showed that after five days of submergence the number of tillers and green leaves per plant decreased significantly compared with CT,dry matter accumulation and chlorophyll content decreased,and oxidative damage was serious. Ultimately,it had an impact on yield. After de-submergence,foliar spraying ASTA could increase the activity of antioxidant enzymes,increase the contents of total soluble sugar and soluble protein,reduce the contents of H2O2 and MDA,alleviate oxidative damage,promote tillering,accelerate dry matter accumulation and reduce yield loss. In particularly,at 12 days after spraying,the number of tillers per plant,green leaves,and the contents of dry matter,chlorophyll a,total soluble sugar and soluble protein of ASTA-0.8 treatment increased significantly,and the activities of antioxidant enzymes increased,and the contents of H2O2 and MDA in leaves decreased. At 7 days after spraying,MDA content was 20.7% lower than CK,and H2O2 content was 9.4% lower than CK. The final yield of ASTA-0.8 treatment was the closest to CT,and the yield returned to 98.7% of CT.[Conclusions] When rice was submerged at tillering stage,foliar spraying 0.8 mmol·L-1 astaxanthin could remedy it. [ABSTRACT FROM AUTHOR]