title: Analysis of reciprocal-transfer experiments to estimate the length of phases having different responses to temperature.
abstract: OBJECTIVE
  The responsiveness of plant ontogeny to temperature may change with plant age. These changes may best be identified by experiments in which individual plants are transferred in a time series from low temperature (LT) to high temperature (HT), and vice versa. Any change in the value of the slope for a plot of the duration taken to complete a developmental phase against time of transfer (either LT to HT or HT to LT) will indicate a change in the temperature responsiveness of development, and the time at which this change occurs. The analysis of this type of reciprocal-transfer experiment is usually performed by regression for each of the visually identified linear sub-phases, separately for the data for LT-to-HT and for HT-to-LT transfers. Here, a mathematical approach is presented using a single curve-fitting procedure.
  
  
  METHODS
  Both LT-to-HT and HT-to-LT transfers are combined in a single curve-fitting procedure. This new, combined approach is illustrated using a published data set for three rice (Oryza sativa) cultivars, where the pre-flowering duration is divided into three sub-phases, and temperature responsiveness is generally stronger during the second than the first and third sub-phases.
  
  
  CONCLUSIONS
  This new model approach provides an objective method, relative to the separate analyses, for assigning data points to a particular sub-phase. Plausible parameter values can be obtained from capturing the whole data of both sets of transfers, which otherwise could not be obtained from the separate-analysis method. Furthermore, the length of sub-phases identified from the LT-to-HT transfers is consistent, in terms of its response to temperature, with that identified from the HT-to-LT transfers. Re-analysis of the published rice data using the new approach reveals that in addition to temperature sensitivity, the optimum temperature of pre-flowering development may vary with plant age. The new approach gives rise to a generalized model for the analysis of reciprocal transfer experiments to quantify age-dependent changes of response of plants (and potentially insects) to any environmental variables that have a significant impact on their development.
authors.affiliation: Crop and Weed Ecology Group, Department of Plant Sciences, Wageningen University, PO Box 430, 6700 AK Wageningen, The Netherlands. xinyou.yin@wur.nl
authors.forename: Xinyou
authors.initials: X
authors.lastname: Yin
mesh_terms: D008954:Models, Biological; D063245:Plant Development; D012107:Research Design; D013696:Temperature