不同施氮量和播种密度对旱地胡麻叶绿体色素含量及干物质量的影响

The Effect of Nitrogen Rate and Seeding Density on the Chlorophyll Concentration and Dry Matter Accumulation of Flax in Dry Land

适当的施氮量和播种密度可以提高胡麻的产量,以陇亚杂1号为研究对象,采用二因素随机区组试验设计,研究3个施氮水平(N1:0 kg/hm^2,N2:75 kg/hm^2,N3:150 kg/hm^2)和3个种植密度水平(D1:450万粒/hm^2,D2:750万粒/hm^2,D3:1050万粒/hm^2)下胡麻各生育时期的叶面积、叶绿体色素含量及干物质量的变化。结果表明,胡麻初花期N3D2与N2D1处理叶面积差异不显著,但与其他处理差异显著,N3D2处理单株叶面积最大,为(242.33±19.58)cm^2。随着胡麻生育进程的推进,叶绿素a的含量表现出上升的趋势,在现蕾期N2D3处理叶绿素a的含量最高(1.24±0.097)mg/g·FW,叶绿素b和类胡萝卜素的含量变化趋势与叶绿素a变化趋势基本相似。苗期、现蕾期各处理茎秆、叶片的干物质量之间无显著差异,花期不同处理下胡麻茎秆干物质量差异显著;N1、N3水平下,随着密度的增加,茎秆、叶片干物质量先增加后降低,且差异显著,其中在N3D2处理下茎秆干物质量最高;同一密度下,随着施肥量的增加,茎秆干物质积累量先增加后降低,但密度增加到一定程度,随施肥量增加,茎秆干物质量变化较小。胡麻成熟期,N3D2的籽粒干物质量最高,N2D1次之,且二者无显著差异。N1D2和N3D2处理提高了胡麻叶面积、叶绿体色素和营养器官干物质量,进而提高了胡麻籽粒产量。在综合考虑减少化肥投入且增产的情况下,N2D1处理是该地区胡麻栽培施氮量和种植密度的最优选择。

Appropriate nitrogen application rate and sowing density can improve the yield of flax.In this study,Longyaza No.1 was taken as the research object,and two-factor randomized block design was adopted,with three nitrogen application levels(N1:0 kg/hm^2,N2:75 kg/hm^2,N3:150 kg/hm^2)and three planting densities(D1:4.5 million seeds/hm^2,D2:75 million seeds/hm^2,D3:10.5 million seeds/hm^2).The results showed that there was no significant difference in leaf area between N3D2 and N2D1 treatments at the early flowering stage of flax,but it was significantly different from other treatments.The leaf area per plant under N3D2 treatment was the largest,which was 242.33±19.58 cm2.With the growing of flax,the content of chlorophyll a showed an upward trend,and the content of chlorophyll a was the highest(1.240.097 mg/g FW)under N2D3 treatment at bud stage,and the change trend of chlorophyll b and carotenoids was similar to that of chlorophyll a.There was no significant difference in dry matter accumulation of stems and leaves among different treatments at seedling stage and budding stage,but there was significant difference in dry matter quality of flax stems under different treatments at flowering stage.At N1 and N3 levels,with the increase of density,the dry matter weight of stem and leaf increased first and then decreased,and the difference was significant,among which the dry matter weight of stem was the highest under N3D2 treatment.Under the same density,with the increase of fertilization amount,the dry matter accumulation of stem first increased and then decreased,but when the density increased to a certain extent,with the increasing of the fertilization amount,the dry matter quality of stem changed little.At the mature stage of flax,the dry matter of N3D2 was the highest,followed by N2D1,and there was no significant difference between them.N1D2 and N3D2 treatments increased the grain yield of flax mainly due to the increase of leaf area,chloroplast pigment and dry matter of nutrient organs.Therefore,considering reducing fertilizer input and increasing yield,N2D1 treatment is the best choice for nitrogen application and planting density of flax cultivation in this area.