赤霉素对不同收获时间的稻草中非结构性碳水化合物含量的影响

赤霉素(GA)处理能有效延缓植株衰老,改善稻草饲用品质,但在对照组成熟时GA处理组还有贪青现象。为了研究GA处理后不同收获时间稻草中非结构性碳水化合物(NSC)含量的差异,本试验选用两优培九(杂交籼稻)、武育粳3号(迟熟中粳)、南粳44(早熟晚粳)和南粳46(中熟晚粳)等4个不同类型的水稻品种,设置3个GA喷施时间:开花后7 d(GA-7),开花后15 d(GA-15)和开花后21 d(GA-21),设置两个收获时间:正常收获(对照组成熟后统一收获)和延迟收获(对照组成熟后推迟6 d收获),测定稻草整株及叶片、茎秆和叶鞘中的NSC包括可溶性碳水化合物(WSC)和淀粉]含量,并利用倒3节茎秆进行徒手切片,观测其中的淀粉颗粒数量。结果表明适时收获的稻草中含有相当数量的NSC,其中粳稻品种高于籼稻品种;稻草中的NSC主要贮存在茎秆中,WSC含量显著高于淀粉含量。延迟收获时不同时间GA处理对改善不同品种稻草中NSC含量的效果出现差异:正常收获时,两优培九以GA-15处理组,武育粳3号以GA-21处理组,南粳44以GA-7处理组的稻草中NSC含量最高;延迟收获时,两优培九以GA-21处理组,武育粳3号以GA-15处理组,南粳44以GA-21处理组的稻草中NSC含量最高;南粳46两次收获均以GA-15处理组的稻草中NSC含量最高。喷施GA能显著增加籼稻品种两优培九和中熟粳稻品种武育粳3号稻草中的NSC含量,而对晚熟粳稻品种南粳44和南粳46稻草中NSC含量的影响不大。

Effects of gibberellic acid on nonstructural carbohydrates content in rice (Oryza sati-va)straw harvested at different times

Gibberellic acid (GA)could effectively delay plant senescence and improve the feed quality of rice (Oryza sativa )straw,but studies have shown that rice plants with applied GA are slow to ripen.In order to investigate the nonstructural carbohydrates (NSC)content of rice straw at different harvest times after GA ap-plication,four different rice varieties have been studied:Liangyoupeijiu (late maturing medium indica ), Wuyujing 3 (late maturing medium japonica ),Nanjing 44 (early maturing late japonica ),and Nanjing 46 (medium maturing late japonica ).The study investigated three GA application times:7 days after anthesis (GA-7),15 days after anthesis (GA-15)and 21 days after anthesis (GA-21).Two harvest times were also set (1:the control grain had reached 80% maturity;2:6 days after harvest time 1).The NSC content including
water soluble carbohydrates (WSC)and starch]in different parts of rice straw have been analyzed.The top 3rd internodes of rice plant were used to make freehand cross-sections to observe the starch granule quantities.The results indicate that the NSC content in rice straw is considerable,with japonica scoring higher than indica va-rieties.The stem is the main storage organ for NSC.WSC content was higher than starch content.At harvest time 1,the optimal GA application time for Liangyoupeijiu was 15 d after anthesis,for Wuyujing 3 21 d after anthesis,and for Nanjing 44 7 d after anthesis.The optimal GA spraying time for Liangyoupeijiu was 21 d af-ter anthesis,15 d after anthesis for Wuyujing 3,and 21 d after anthesis for Nanjing 44.For Nanjing 46,the optimal GA application time at both harvest times was 15 d after anthesis.Spraying GA during the late growth period could effectively increase the NSC content in rice straw for the indica rice variety Liangyoupeijiu and the medium japonica rice variety Wuyujing 3,but the effects for late maturing japonica varieties Nanjing 44 and Nanjing 46 were not significant.