穿刺针直径及校准方法对叶片穿透力机械强度的影响（附录）

Effects of punch needle diameters and calibration methods on leaf force to punch mechanical strength

关键词:  叶片穿透力, 穿透力差异, 叶片密度, 比叶重, 角质层厚度, 叶脉密度

Key words:  leaf force to punch, differences of force to punch, leaf density, leaf mass per area, cuticle thickness, vein density

摘要:

叶片穿透力强度是反映叶片机械抗性的重要指标之一,但最终结果受到针直径与校准方法的影响。为探究不同穿刺针直径及校准方法对叶片穿透力测定的影响,该文对比研究了广西大学校园中30种具平行脉单子叶植物与具网状脉双子叶植物的叶片穿透力在不同直径穿刺针测定与校准条件下的差异及该差异与功能性状的相关性。结果表明:(1)利用穿刺针周长、横截面积及叶片厚度等进行校准,不同校准方式下不同直径穿刺针测定的叶片穿透力不同。(2)不同校准方式下,利用3种直径穿刺针测到的穿透力之间差异不同,其中,在只利用穿刺针周长和利用针周长与叶片厚度校准后,不同直径穿刺针之间的叶片穿透力无显著性差异; 在只利用叶片厚度校准时,穿刺针越粗,穿透力越大; 在只利用穿刺针面积和利用针面积与叶片厚度校准后,穿刺针越粗,穿透力越小。单子叶植物3种不同直径穿刺针的穿透力均大于相同粗细穿刺针下双子叶植物的穿透力。(3)不同校准方式下3种直径穿透力之间的差异与叶片性状的相关性有所不同,叶脉类型、叶片密度、比叶重、角质层厚度和叶脉密度可能是3种直径穿透力之间差异产生的结构影响因素。综上所述,利用不同直径穿刺针测定及不同校准方式下对不同叶脉类型植物的叶片穿透力具有不同影响,叶片穿透力测定过程中需对穿刺针直径及校准方法进行合理地选择和统一,建议测定叶片穿透力时,这3种针中,直径为0.5 mm的穿刺针应用于叶脉密度较大、比叶重较小的叶片测定,但不适用于较为坚硬的叶片,直径为2 mm的穿刺针不适用于叶脉密度较大、比叶重较小的叶片,选择直径为1 mm的穿刺针并利用其周长进行校准较为合理。

Abstract:

The leaf force to punch strength is one of the important indexes to reflect the mechanical resistance of the leaf, but the final result is affected by the needle diameter and calibration method. To analyze the influence of different punch needle diameters and calibration methods on force to punch measurement, the difference of leaf force to punch of 30 plants with parallel vein monocots and dicots with reticulate veins under different diameters punch needle and their calibrations with functional traits from the campus of Guangxi University were measured. The results were as follows:(1)The force to punch was calibrated based on the needle circumference, cross-section area and leaf thickness. The measured force to punch varied with needle diameter and calibration method.(2)The differences among the leaf force to punch of the three diameters punch needle were different under different calibration methods. Among them, there was no significant difference in the force to using punch needles with different diameters when calibrated by punch needles circumference and needles circumference combining the leaf thickness. When only using leaf thickness for calibration, the thicker the punch needles, the force to punch increased with needle diameters, but it decreased when only using the needle cross-section area or combining the cross-section area with the leaf thickness for calibration. In addition, the leaf force to punch of monocots was significantly higher than that of dicots.(3)As the variation range of force to punch across needle diameter was calculated for each species, the correlation between this variation range and leaf traits differed with calibration methods. Vein type, leaf density, leaf mass per area, cuticle thickness and vein density significantly influenced this range. Overall, needle diameters and calibration methods significantly affect the accuracy of leaf force to punch measurements across plant groups with different venation types. We advise carefully selecting perforation needles and calibration methods for force to punch measurements based on the research questions and studied plant groups. It is suggested that the punch needle with a diameter of 0.5 mm should be applied to the blade with large vein density and small leaf mass per area, but not to the hard leaves; the needle with a diameter of 2 mm should not be applied to the blade with large vein density and small leaf mass per area. It is more reasonable to choose the needle with a diameter of 1 mm and use its circumference for calibration in three diameters.