春小麦籽粒灌浆期降落值动态规律及氮磷肥与播期效应的研究

利用不同品质类型春小麦品种野猫、东农7742和新克旱9，在施肥和播期试验基础上，通过建立灌浆期籽粒降落值变化的曲线拟合方程，定量揭示其动态规律以及氮磷肥与气象条件的影响效应。结果表明，灌浆期籽粒降落值随时间变化符合一元三次多项式凸性曲线，即呈自开花始先增后降的单峰曲线变化。曲线方程各特征量具有相应的生物学意义；基因型与环境要素的影响可由方程系数和特征量体现。在富钾情况下，氮用量增加，高蛋白强筋品种降落值增加，动态曲线最高值上升且出现时间推迟，而高蛋白中筋和低蛋白弱筋品种降落值降低，最高值下降且出现时间提前。磷用量增加，各基因型降落值均降低；动态曲线最高值、最低值及出现时间因基因型而异。氮磷（钾）平衡配施是形成较高降落值（较低α-淀粉酶活性）的关键。在没有水分胁迫情况下，光温互作是影响各基因型籽粒降落值动态的首要条件，其次为降水；而光温因子中，光合有效辐射为最敏感因子。较高的光温条件互作是形成各品种较高降落值的基础。在此前提下增加光合有效辐射使高蛋白强筋品种降落值增加；并且在一定水平的光照条件限度内，增加光合有效辐射使高蛋白中筋和低蛋白弱筋品种降落值增加，超过限度反而使其降低。气象条件的影响及基因型差异可通过曲线的变化反映出来。灌浆期高蛋白中筋和低蛋白弱筋品种降落值受氮磷肥影响大于高蛋白强筋品种，受气象条件影响则小于高蛋白强筋品种。就高蛋白强筋品种而言，气象条件的影响程度大于氮磷肥；而对于高蛋白中筋和低蛋白弱筋品种，氮磷肥的影响大于气象条件。

Dynamic of Grain Falling Number in Spring Wheat and Effects of Nitrogen, Phosphorus Fertilizer and Sowing Date on It during Grain Filling

More attention has been paid to wheat grain falling number (GFN) that is an important index indicating α-amylase activity and quality property of wheat. Limited published information of GFN dynamics and the effects of environmental conditions on it during grain filling are known. In the present paper, the field experiments of N and P application and sowing date in Harbin in 2002 were conducted to investigate the dynamic pattern in GFN and how it was affected by the N and P fertilizer and meteorological conditions during grain filling using three genotypes of spring wheat with high protein-rich gluten (Wildcat), high protein-medium gluten (DN7742) and low protein-poor gluten（NKH9）. The N and P application treatments included F1 (N: 225 kg/ha, P₂O₅: 450 kg/ha)，F2 (N: 300 kg/ha, P₂O₅: 300 kg/ha), F3 (N: 300 kg/ha, P₂O₅: 450 kg/ha) and F4 (N: 300 kg/ha, P₂O₅: 600 kg/ha). The least squares method was used to finish the curve fitting of the dynamic pattern in the grain falling number. The results showed that the dynamic changes in GFN with the increase of days after anthesis could be fitted to a third-order convex curve，i.e. GFN rose in the initial stage and then fell in mid-late stage, and the effects of genotypes and environmental factors on GFN could be expressed by the coefficients and characteristic variables of the curve equation. From the 15th day after anthesis to maturity, with increasing nitrogen in medium phosphorus under high kalium level, GFN and the curve highest value were increased and its corresponding time postponed in high protein-rich gluten genotype, but there were on the contrary in both high protein-medium gluten and low protein-poor gluten genotypes. And GFN in the three genotypes all decreased with increasing phosphorus in medium or low nitrogen and high kalium level, and the characteristic variables of the curve equations varied with different genotypes. The balance fertilization of nitrogen, phosphorus and kalium was the key to get a higher GFN (lower α-amylase activity). Under the condition of moderate rainfall, the interaction of temperature and sunlight was the predominant factor affecting GFN in different genotypes during grain filling, and rainfall was the second one; PAR was the most sensitive meteorological element influencing GFN dynamics. The interaction of higher sunlight and temperature was the basis of higher GFN in different genotypes. Under the precondition of the interaction of higher sunlight and temperature, GFN in high protein-rich gluten genotype was increased with increasing PAR in a certain range while decreased when PAR was beyond the range in both high protein-medium gluten and low protein-poor gluten genotypes. The effects of meteorological conditions and differences among genotypes could be indicated by the dynamic curve changes. High protein-medium gluten and lower proten-poor gluten genotypes were affected more by nitrogen and phosphorus fertilizer but less by meteorological conditions than high protein-rich gluten genotype. Comparatively, high protein-rich gluten genotype was more sensitive to meteorological factors while high protein-medium gluten and lower protein-poor gluten genotypes were more sensitive to nitrogen and phosphorus fertilizer.