基于图像几何信息的遮荫条件下茄衣烟叶形态特征分析与叶面积生长模型构建

Morphological characteristics analysis and leaf area growth model construction of wrapper tobacco leaves under shading conditions based on image geometric information

  • 摘要: 【目的】筛选遮荫影响茄衣烟叶的关键形态特征指标,建立茄衣烟叶叶面积生长模型,明确遮荫条件下茄衣烟叶动态发育规律,以期为国产茄衣烟叶精准栽培提供理论依据。【方法】以雪茄烟品种CX81为试验材料,设3个遮荫处理,分别为透光率60%(T1)、透光率70%(T2)和透光率100%不遮荫对照(CK)。基于图像几何信息提取烟叶形态特征,测定上、中、下3个叶位叶片的动态生长指标,对不同透光率下茄衣烟叶的形态特征进行正交偏最小二乘判别分析(OPLS-DA),并建立叶面积生长模型。【结果】OPLS-DA结果表明,上、中、下部烟叶在不同透光率处理下的形态特征参数存在明显差异,随着叶位提高,受遮荫影响的形态指标逐渐减少,3个部位的共同指标有叶面积生长速率、叶面积、叶周长和茎叶夹角。遮荫条件下,叶面积与遮荫时间的关系符合Richards模型,其方程为y=a/ (1+eb-cx)1/d,模型稳定性好,拟合程度高,具备生物学意义。随着透光率增加,叶面积先增大后减小,T2处理叶面积最大,遮荫45 d时,T2处理的叶面积较CK增加4.7%~17.4%;同一部位烟叶平均生长速率呈慢—快—慢的变化规律,T2处理叶面积平均生长速率最大,较CK提高5.5%~13.4%。【结论】叶面积生长速率、叶面积、叶周长和茎叶夹角是影响遮荫条件下茄衣烟叶叶片形态的关键指标,Richards模型可有效预测遮荫条件下茄衣烟叶叶面积生长,70%透光率可加快叶面积生长速率,有效提高叶面积。

     

    Abstract: 【Objective】The key morphological characteristics of wrapper tobacco leaves under shading were screened, the area growth model of wrapper tobacco leaves was established,and the dynamic development regulation of wrapper to-bacco leaves under shading conditions was clarified,in order to provide theoretical reference for the precise cultivation of domestic wrapper tobacco leaves.【Method】The cigar variety CX81 was used as the experimental material,and three shading treatments were set up,which were light transmittance 60%(T1),light transmittance 70%(T2)and no shading with light transmittance 100%(CK). Based on the image geometric information,the morphological characteristics of tobacco leaves were extracted,and the dynamic growth indexes of leaves at three leaf positions(upper,middle and lower positions) were determined. The morphological characteristics of tobacco leaves under different light transmittance were analyzed by partial least squares discriminant analysis(OPLS-DA),and the leaf area growth model was established.【Result】OPLS-DA results showed that there were obvious differences in the morphological characteristics parameters of upper,middle and lower tobacco leaves under different light transmittance treatments. With the increase of leaf position,the morphological indexes affected by shading gradually decreased. The common indexes of the three parts were leaf area growth rate,leaf area,leaf circumference and stem-leaf angle. Under shading conditions,the relationship between leaf area and shading time conformed to Richards model,and the equation was y=a/ (1+eb-cx)1/d. The model had good stability,high fitting degree and biological significance. With the increase of light transmittance,the leaf area increased first and then decreased,the leaf area of T2 treatment was the largest,and when shading for 45 d,the leaf area of T2 treatment increased by 4.7%-17.4% compared with CK. The average growth rate of tobacco leaves in the same position showed a slow-fast-slow change regulation,and the average growth rate of leaf area under T2 treatment was the highest, which was 5.5%-13.4% higher than that of CK.【Conclusion】The leaf area growth rate,leaf area,leaf circumference and stem-leaf angle are the key indexes affecting the leaf morphology of wrapper tobacco leaves under shading conditions. Richards model can effectively predict the area growth of wrapper tobacco leaves under shading conditions. 70% light transmittance can accelerate the growth rate of leaf area and effectively increase leaf area.

     

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