Estimativa da área foliar de plantas daninhas de ambiente aquático: Pistia stratiotes

Abstract

A área foliar é uma das principais características para avaliar o crescimento vegetal. Objetivou-se neste trabalho determinar uma equação matemática para estimar a área foliar de Pistia stratiotes a partir de dimensões lineares dos limbos foliares. A pesquisa foi desenvolvida na Universidade Estadual Paulista, Jaboticabal-SP, Brasil. Cem folhas, coletadas no ambiente natural, foram eletronicamente medidas em comprimento (C), largura máxima (L) e área foliar (AF). Os dados de AF e C × L foram submetidos à análise de regressão linear, determinando-se uma equação matemática para estimar a área foliar da espécie. A análise de variância sobre a regressão linear e a análise de correlação entre os valores de área foliar e estimada foram significativas (p < 0,01). A área foliar de P. stratiotes pode ser estimada pela equação: AF = 0,79499 (CL).

Non-destructive equations to estimate the leaf area of Styrax pohlii and Styrax ferrugineus

“…Many studies have been reported and propose non-destructive equations to estimate the growth of leaves in crops ( Tsialtas and Maslaris, 2005;Peksen, 2007;Olfati et al, 2010;Rouphael et al, 2010) and weeds (Carvalho et al, 2011a;Carvalho et al, 2011b). However, specifically for Cerrado woody species, there are not any models like the one proposed in the present paper, and consequently, experiments have to be conducted in a way that leaves must be excised.…”

“…We selected equations number 5 and number 10 because they presented the highest R 2 , which must be the selective criterion, as proposed by Carvalho et al (2011b). Many studies have been reported and propose non-destructive equations to estimate the growth of leaves in crops ( Tsialtas and Maslaris, 2005;Peksen, 2007;Olfati et al, 2010;Rouphael et al, 2010) and weeds (Carvalho et al, 2011a;Carvalho et al, 2011b).…”

“…The most common equations are based on general linear (Carvalho et al, 2011a), simple linear (Carvalho et al, 2011b), square (Severino et al, 2007) and exponential regressions (Bianco et al, 2005). The best model for estimating LA through equations works better when the measures to be taken can be easily and correctly identified and the equations are based on only one or few measurements (Severino et al, 2007).…”

Predicting red cypress vine leaf area by a linear equation

“…Linear equations are the easiest way to determine leaf area (Carvalho et al 2011). In addition, the use of regression equations is a simple, fast, accurate, and reliably method to predict leaf area, allowing to monitor leaf growth and expansion from the same plant until the end of life cycle or experiment (Gemiely et al 1991).…”

“…Therefore, equations derived from nondestructive models represent a fast method providing leaf area estimates with no leaf excisions (Norman and Campbell 1989). Linear models based on length and width leaf measurements have been considered the most simple and efficient models to estimate the leaf area of some species in that, for a better practical use, researchers can choose the simple linear model (Y=a*X), considering the product of length and width as the variable "X", as described by Carvalho et al (2011). The objective of this research was to determine a linear equation (Y=a*X) to predict the leaf area of Ipomoea quamoclit L. (red cypress vine), an important weed infesting perennial crops in Brazil and worldwide, as a function of leaf length and leaf width.…”