基肥配比和拔节期追施氮肥对糯玉米淀粉胶凝和回生特性的影响

Starch Gelatinization and Retrogradation Properties under Different Basic Fertilizer Regimes and Nitrogen Topdressing at Jointing Stage of Waxy Maize

以苏玉糯4号为材料,采用二因素裂区设计,研究了不同基肥配比(纯N75kghm-2、纯N75kghm-2+K2O70kghm-2、纯N75kghm-2+P2O565kghm-2和纯N75kghm-2+P2O565kghm-2+K2O70kghm-2)和拔节期追氮(0、150和300kghm-2)对糯玉米淀粉胶凝和回生特性的影响。结果表明,淀粉和回生淀粉的起始温度、峰值温度和终值温度虽然受到施肥处理的影响,但总体上变异较小。热焓值受基肥配比影响较小,糊化范围和峰值指数受拔节期追施氮肥量影响较小。在不同基肥配比处理下,糊化范围在基施氮钾时最低,氮磷钾合理配施处理下最高,峰值指数表现和糊化范围相反。在拔节期不同追氮量处理下,热焓值以追氮150kghm-2最高,追氮300kghm-2或不追氮无显著差异。胶凝淀粉冷藏后发生回生,表现为转变温度、热焓值和峰值指数降低,糊化范围变宽。和仅基施氮相比,增施磷或(和)钾都可降低淀粉的回生值和回生淀粉的热焓值,拔节期追氮处理的这两项指标均劣于不追氮处理。回生值与回生淀粉的热焓值和峰值指数显著正相关,相关系数分别为0.90(P<0.01)和0.41(P<0.05);原淀粉的热焓值与峰值指数极显著正相关,相关系数为0.65(P<0.01),与回生淀粉热焓值显著正相关,相关系数为0.44(P<0.05),与终值温度显著负相关,相关系数为-0.41(P<0.05)。在本试验条件下,以氮磷钾均衡基施并拔节期追氮150kghm-2时,淀粉胶凝和回生特性较为理想,表现为热焓值较高,回生值较低。

Proper fertilizer managements can improve the starch gelatinization and retrogradation properties of waxy maize （Zea mays L. Ceratina Kulesh）. The split-design experiment was conducted using waxy maize cultivar Suyunuo 4 with four main plots subjected to basal fertilizer treatments of N 75 kg ha^-1, N 75 kg ha^-1＋K20 70 kg ha^-1, N 75 kg ha^-1＋p205 65 kg ha^-1, and N 75 kg ha^-1＋PEO5 65 kg ha^-1＋K20 70 kg ha^-1, respectively in 2007 and 2008. The three split plots were topdressed with nitrogen of 0, 150, and 300 kg ha^-1 at jointing stage, respectively. Though onset temperature （To）, peak temperature （Tp） and conclusion tem- perature （To） of native starch and retrogradated starch were affected by fertilizer treatments, the variation was little. No significant effects were observed for basic fertilizer treatments on the enthalpy of gelatinization （AHget）, and for N topdressing treatments on gelatinization range （R） and peak height index （PHI）. The R-value was the lowest in the treatment with only N and K in basal fertilizer, and the highest in the treatment with N, P, and K in basal fertilizer. The changes of PHI showed an opposite trend to R. The △Hget was the highest in the treatment with medium N topdressing （150 kg ha^-1）. Gelatinized starch became retrograded with lower To, Tp, To, enthalpy of retrogradation （AHret）, and PHI, as well as wider R. Compared with the treatment of only N applied in basal fertilizer, the percentage of retrogradation and △Hret decreased when P and/or K added in the basal fertilizer. The two indicators were higher in the treatments with N topdressing than without N topdressing. The percentage of retrogradation was positively correlated with △Hret （r = 0.90, P 〈 0.01） and PHI of retrograded starch （r = 0.41, P 〈 0.05）. △Hgel was positively correlated with PHI （r = 0.65, P 〈 0.01） and Anret （r = 0.44, P 〈 0.05）, but negatively correlated with Tc （r = -0.41, P 〈 0.05）. It is recommended to apply balanced fertilization with N, P, and K combining with moderate N topdressing under conditions similar to the experiment to improve gelatinization and retrogradation properties of waxy maize starch.