氮素不同控释期对甘薯光合特性及干物质积累与分配的影响

Effects of different controlled release periods of nitrogen on photosynthetic characteristics and dry matter accumulation and distribution of sweet potato

以甘薯[Ipomoea batatas(L.)Lam.]品种济薯25为试材,在大田条件下,设置控释期为30 d(T30)、50 d(T50)、70 d(T70)、90 d(T90)4个氮素控释肥处理,以施用等量养分含量的普通复合肥作为对照(CK),研究不同氮素控释期对甘薯光合特性及干物质积累与分配的影响。结果表明,氮素适当控释(控释期30~70 d)提高了甘薯中后期(80~160 d)叶片光合性能,促进了干物质向地下部的快速积累和转运分配,甘薯中后期叶片光合指标、地下部干物质积累(积累量和积累速率)和分配(分配比例和根冠比)指标均明显高于对照,其中以T50、T70较好,收获期(160 d)2个处理净光合速率、叶绿素SPAD、地下部干物质积累量、根冠比分别比对照提高了14.01%、11.32%、21.75%、18.48%和15.62%、11.84%、20.65%、18.84%;当控释期达90 d时,后期(120~160 d)地下部干物质积累与分配指标均低于对照,说明氮素控释期过长不利于甘薯后期干物质向地下部的快速积累和转运分配。

Four nitrogen fertilizer treatments with different controlled release periods of 30 d(T30),50 d(T50),70 d(T70)and 90 d(T90)were set up in the field to investigate the effect of the controlled release periods of nitrogen on photosynthetic characteristics,dry matter accumulation and distribution of sweet potato[Ipomoea batatas(L.)Lam.],with the cultivar JiShu25 as the test material and using common compound fertilizer with equal nutrient content as control(CK).The results showed that the appropriate controlled release periods(30~70 d)of nitrogen improved the photosynthetic performance of sweet potato leaves in the middle and late stage(80~160 d),and promoted the rapid accumulation and transfer of underground dry matter of sweet potato.The photosynthetic terms,dry matter accumulation(accumulation amount,accumulation rate)and distribution(distribution ratio,root-shoot ratio)index of sweet potato leaves in the middle and late stage were significantly higher than CK.Among them,the treatment with controlled release periods of nitrogen of 50 d and 70 d were better.The photosynthetic rate,chlorophyll SPAD,underground dry matter accumulation amount,root-shoot ratio of T50 and T70 increased by 14.01%,11.32%,21.75%,18.48%and 15.62%,11.84%,20.65%,18.84%in the har-vest time(160 d).Underground dry matter accumulation and distribution index in the late stage(120~160 d)were lower than CK when the controlled release periods of nitrogen achieved 90 d.This indicated that long controlled release periods of nitrogen had an in-hibiting effect on the rapid accumulation and transfer of underground dry matter of sweet potato.