NON-DESTRUCTIVE METHOD TO DETERMINING THE LEAF AREA IN HEMP, Cannabis sativa L.

Abstract

The evaluation of the leaf surface of hemp leaves, Cannabis sativa L., was the subject of the present study. The biological material was represented by the hemp variety 'Silvana', cultivated in SCDA Lovrin, Romania. Hemp leaves were taken randomly from mature plants. The leaves were herborized immediately after harvesting, in the field, in order to preserve the configuration of the leaves for analysis. Each leaf was scanned in a 1:1 ratio. The leaves were measured in terms of length (in the direction of the central leaflet) and width (maximum opening of the leaflets). For the measurement, a precision of ±0.5 mm was ensured. The scanned leaves were analyzed and the perimeter (Per) and scanned leaf area (SLA) were obtained. The correction factor (CF) was determined in order to be used for calculating the measured leaf area (MLA) by non-destructive methods. The value CF=0.27 was found, where the error as the difference between MLA and SLA (considered as a reference) was minimal (ME=0.87 cm2). The calculation of the RMSEP parameter confirmed the value of the correction factor (0.27), at which the RMSEP value was the minimum (RMSEP=9.74929). The fitting relationship between MLA and SLA was described by a linear equation, under conditions of R2=0.952, p<0.001. Polynomial equations of the 3rd degree described the interdependence relationship between SLA and parameters L (R2=0.932) and w (R=0.964) of the leaves, and a polynomial equation of the 2nd degree described the relationship between SLA and Per (R2=0.995). Stronger correlation levels were identified between MLA and dimensional parameters of leaves (L, w; r=0.969 for MLA with L; r=0.974 for MLA with w), than between SLA and dimensional parameters of hemp leaves (r =0.927 for SLA with L; r=0.957 for SLA with w). This difference can be explained based on the methods of determining SLA (by scanning) and MLA (by measurement, based on L, w, CF), MLA having a direct relationship between L and w from the calculation relationship, a fact that confirms the usefulness of the work method.

Intra‐leaf modeling of Cannabis leaflet shape produces leaf models that predict genetic and developmental identities

“…(1973) and later Anderson (1980), who was the first to quantify the width, length, and ratio of the central leaflet. This or similar methods were then commonly used in studies investigating the morphological characteristics of Cannabis species, subspecies, cultivars, biotypes, and chemotypes (Small et al ., 1976; de Meijer et al ., 1992; de Meijer & Keizer, 1996; Hillig, 2005a; Clarke & Merlin, 2013; Lynch et al ., 2016; Karlov et al ., 2017; Parsons et al ., 2019; McPartland & Small, 2020; Carlson et al ., 2021; Islam et al ., 2021; Jin et al ., 2021a; Vergara et al ., 2021; Buzna & Sala, 2022; Chen et al ., 2022; Murovec et al ., 2022), often with contradictory results. Leaf shape has therefore played an important and sometimes controversial role in Cannabis taxonomy.…”

Leaf Area Estimation by Photographing Leaves Sandwiched between Transparent Clear File Folder Sheets

“…The main advantage of the ME is that it allows for non-destructive estimation of leaf area through the simple measurement of leaf length and width in situ. The ME has been widely used to estimate the leaf areas of various plant species, including woody plants [26,27], herbaceous plants [26,28,29], lianas [26,30], monocots [26,31,32], Magnoliids [25,26], ferns [26], and important crop species such as maize [33], pear [34], and grapes [35,36]. However, to apply the ME to estimate leaf area, a species-specific proportionality constant, known as the Montgomery parameter, must be determined in advance.…”