1982/09/01 by R. HUNT, Roderick Hunt · 1 citation
Agricultural and Biological Sciences · Environmental Science · #Greenhouse Technology and Climate Control #Leaf Properties and Growth Measurement #Plant Water Relations and Carbon Dynamics
paper · doi:10.1093/oxfordjournals.aob.a086371
openalex publication_date 1982/09/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/29
Recent work employing splined cubic polynomial exponentials as fitted plant growth curves has been extended to include the second derivatives of the splines and their variances. For variates Y and Z plotted against time, T, three new quantities have been derived: (1) the RGR-rate, or the acceleration of In Y in T, d[(1/Y) (d Y/dT)]/dT, and similarly for Z; (2) the relative acceleration rate, (1/Y) (d2Y/dT2), and similarly for Z; and (3) the unit acceleration rate, (1/Z) (d2Y/dT2). A computer program which derives these quantities, and their errors, from splines fitted to experimental data is described and offered for circulation, and the biological relevance of the new quantities is exemplified by means of analyses of both classical and new data.