基于归一化法的烤烟干物质积累建模与特征分析

摘要

为探讨不同株型烤烟品种干物质积累动态模型和变化特征,实现不同品种烤烟干物质积累的有效预测,以不同株型品种云烟97、NC71、K326为材料,采用田间实测和数值模拟方法研究4个密度(13890、15150、16660和18510株hm–2)水平下烤烟干物质积累动态,分析关键生长参数特征,以期为烤烟合理密植、烟叶增产提供新的理论与方法.结果表明:(1)基于归一化法筛选并建立了相对干物质积累量与相对生长时间的干物质积累动态模型(MMF),方程表达式为y=(ab+cxd)/(b+xd),模拟准确度k值在0.9032~1.0482之间,决定系数R2在0.94以上,进一步推导发现,方程具有过原点性、有界性、单调递增性等特点,符合生物学意义,能较好地模拟烤烟干物质积累动态特征;利用该模型分析积累特征参数,将烤烟干物质积累过程划分为缓慢增长期、快速增长期、减速增长期.(2)随着种植密度的增加,烤烟速率峰值出现时间(Tm)、快速增长期开始时间(RT1)、结束时间(RT2)均有不同程度提前;密植条件下(D3、D4),NC71和K326快速增长期持续时间(Td)及其积累比例(Ra)明显提升;通径分析表明,Td、Ra均能影响烤烟最终干物质积累水平,其与干物重均显著(0.6500*)或极显著(0.7758**)正相关,其中Ra对干物重直接通径系数达1.7097,对回归方程的总贡献率也达1.3264.(3)耐密性表现为筒型>鼓型>塔型,对应品种K326、NC71、云烟97的适宜密度分别为18510株hm–2(D4)、16660株hm–2(D3)、15150(D2)~16660(D3)株hm–2.%To investigate a model to simulate and effectively predict the dynamic dry matter accumulation (DMA) character in different flue-cured tobacco varieties. We conducted a field experiment using three plant types of Yunyan 97, NC71, and K326 with four density treatments of 13890, 15150, 16660, and 18510 plants ha–1. To measure and simulate growth parameters, hop-ing to provide a new theory and method for rational close planting and higher productivity. A MMF curve equation,y= (ab+cxd)/(b+xd), was developed for relative DMA and relative accumulated time by the normalization method. The dynamic model could make a good estimation for DMA dynamics with the accuracies (k) of 0.9032–1.0482, and the precision (R2) above 0.94. It was also found that the equation had the characteristics of the origin, the boundedness and the monotone increasing, and it was in accordance with the biological significance. The DMA of flue-cured tobacco was divided into the slow growing stage, rapid growing stage and decelerated growing stage with further analysis of its characteristic parameters. The time to maximum rate (Tm), the initiation time and ending time of rapid growing stage showed different degrees of advance with increasing plant density. The duration (Td) and accumulation radio (Ra) of rapid growing stage increased significantly under the condition of high density (D3, D4). Path analysis indicated thatTd orRasignificantly correlated with DMA (0.6500*, 0.7758**), the direct path coef-ficient ofRa was 1.7097 and its regression contribution also reached 1.3264. The density-tolerance in different plant types was manifested as Piping (K326) > Drum (NC71) > Tower (Yunyan 97), with the suitable planting density of 18510 (D4) plant ha–1, 16660 (D3) plant ha–1 and 15150 (D2) – 16660 (D3) plant ha–1,respectively.