栽植密度与氮肥用量对茎瘤芥茎瘤形态特征及空心发生规律的影响及相互关系

为探讨栽植密度与氮素施用量对榨菜茎瘤形态特征的影响及茎瘤空心发生规律,设置3个栽植密度(行株距为40 cm×40 cm、40 cm×30 cm、30 cm×20 cm)与3个氮素施用水平(100、300、500 kg/hm²),研究不同栽植密度与氮素施用水平对榨菜单茎质量、茎瘤横纵径、空心率及空心指数等指标的影响,并探讨茎瘤各形态指标与空心率的相互关系。试验结果表明,栽植密度30 cm×20 cm搭配300 kg/hm²氮肥施用时能够调控茎瘤形态指标,降低空心率,具有最优产量表现;而在40 cm×40 cm栽植密度下,增施氮肥显著促进茎瘤横纵径,但由于茎瘤空心高发,导致产量明显降低。同时,茎瘤形态特征指标与空心率的相关关系与通径分析表明,茎叶比、单茎瘤鲜质量、腋芽发生率、单茎腋芽发生数与茎瘤横纵径呈极显著正相关关系(r=0.57~0.75),而与菜形指数呈极显著负相关关系(r=-0.51);对茎瘤空心率直接影响较大的指标分别为茎瘤横径(1.91)与菜形指数(1.38),而其他指标均通过菜形指数作用于空心发生率(-1.24~-0.34),表明菜形指数是影响茎瘤芥空心发生的重要因素,其中横径的伸长为茎瘤空心发生的主要因子。

Effects of Planting Density and Nitrogen Application Rate on Stem Morphological and Hollow Heart Characteristics of Tumorous Stem Mustard

Three planting densities(row spacing of 40 cm×40 cm,40 cm×30 cm,30 cm×20 cm)and three nitrogen application rates(100,300,500 kg/hm2)were set up,and the effects of planting densities and nitrogen application rates on single stem weight,horizontal and vertical diameter,hollow heart percentage and index were studied,furthermore,the correlation between the morphological indexes and stem hollow heart percentage was discussed.The results showed that,the treatment with planting density of 30 cm×20 cm and nitrogen application amount of 300 kg/hm2 could regulate the morphological indexes,and reduce hollow heart percentage,in addition,it showed the best yield performance.While under the planting density of 40 cm×40 cm,the increasing application of nitrogen could significantly promote horizontal and vertical diameter,but due to the high incidence rate of stem hollow heart,the yield reduced obviously.The correlation relationship between the morphological characteristics and hollow heart percentage and path analysis showed that the stem-leaf ratio,fresh weight of a single stem,leaf bud percentage,and number of axillary bud of a single stem were extremely significantly positively correlated with horizontal and vertical diameter(r=0.57-0.75),but were extremely significantly negatively correlated with vegetable shape index(r=-0.51).Stem horizontal diameter and stem shape index had the highest direct effect on hollow heart ratio(1.91 and 1.38),and other indexes had indirectly negatively effect on hollow heart ratio through vegetable shape index(from-1.24 to-0.34),which indicated that stem shape index was an important factor affecting the occurrence of hollow heart in mustard,and the horizontal diameter was the main factor.