Experiments

Three experiments were conducted. Exp. 1 and Exp. 2 aimed at evaluating the ability to simulate accurately the spatial variability in irradiance in two cases: (i) within the growth chamber in absence of plants (Exp. 1), when the anisotropic distribution of irradiance is generated by the growth chamber and its lighting system, and (ii) within a canopy in the growth chamber (Exp. 2), when plant architecture and optical properties contribute to the anisotropic distribution of irradiance. Exp. 3 aimed at illustrating how simulations can be used to give new insights in the regulation of a biological process using rose bush as plant species. Spectra measurements of incident irradiance were performed in the three experiments with a spectrophotometer (Avaspec-2048, Avantes, Eerbeek, Netherlands) measuring in the range 338 to 875 nm, with a spectral resolution smaller than 1 nm and equipped with a cosine corrector sensor to integrate the radiation on a half hemisphere.

from openalea.rose.experiment import *
from oawidgets.plantgl import PlantGL
from openalea.plantgl.all import *
from openalea.rose.data import manips, experiments
from ipywidgets import interact_manual, interactive, Dropdown, Checkbox

/home/docs/checkouts/readthedocs.org/user_builds/openalea-rose/conda/latest/lib/python3.12/site-packages/openalea.core-2.4.2-py3.9.egg/openalea/core/pkgmanager.py:49: UserWarning: pkg_resources is deprecated as an API. See https://setuptools.pypa.io/en/latest/pkg_resources.html. The pkg_resources package is slated for removal as early as 2025-11-30. Refrain from using this package or pin to Setuptools<81.
  from pkg_resources import iter_entry_points

opts = list(map(str, list(range(len(get_all_manips())))))
manips_opts_exp3 = sorted(list(map(str, list(manips()))))
stage_opts_exp3 = ["FBV","PCV","OF"]

Experiment °1

In Exp. 1, only one group of four 400 W lamps were turned on (i.e. one 400W lamp in each quarter of the ceiling). Spectral measurements were taken by pointing the sensor upward (elevation angle 90°) in a quarter of the chamber, assuming that they were representative of the whole growth chamber due to its symmetry. 360 measurement points were distributed according to a 10 cm x 10 cm mesh on three horizontal planes, at 10 and 50 cm above the table (corresponding to the height of Exp. 2-3 plants base and top, respectively, Fig. 3A), and at 90 cm above the table (close to the lamps, 17 cm under the panel separating the lamp and plant compartments).

exp1 = PlantGL(environment() + sensor_exp(0), side='double')
exp1

Experiment °2

In Experiment 2, the light sensor, pointing either upward (red spots) or sideward (blue spots), was moved along a vertical transect at the center of the growth chamber (vertical to site 4), each 5 cm from 10 to 50 cm above the table. The sensor was also moved along two horizontal transects, one at 10 cm above the table vertically from sites 2 to 6, sensor pointing upward (red dots); and a transect at 25 cm above the table vertically from sites 1 to 7, sensor pointing sideward (blue dots). The sideward pointing sensor faced the wall in front of site 7.

def select_disposition(configuration):
    env = environment()
    exp2 = PlantGL(env + sensor_exp(1) + experiment2(configuration), side='double', group_by_color=False)
    display(exp2)

configuration=Dropdown(options=["1","2","3","4","5"], value="1")

w = interact_manual(select_disposition, configuration=configuration)

Experiment °3

In Exp. 3, rose plants, obtained from cuttings, were grown in 500 ml pots at a density of ca. 44 plants m-2 under two different light intensity regimes: (i) a constant high irradiance (HH treatment; PPFD ca. 420 μmol m-2 s-1 at 30 cm above the culture table) until the petals of the flower bud became visible (petal colour visible stage; PCV), (ii) a low irradiance (PPFD ca. 100 μmol m-2 s-1 at 30 cm above the culture table) during the 16 days before the flower bud was visible on the primary axis (flower bud visible stage, FBV) followed by a high irradiance similar to HH treatment (LH treatment) until PCV stage. From FBV, the development stage (dormant or outgrowing) of each axillary bud along the primary axis was scored every two or three days on 12 plants per treatment. An axillary bud was considered to start its outgrowth when its first leaf was clearly visible between its scales. At FBV, plants consisted of a primary axis topped by the floral bud with ca. 8-9 foliated leaves and an axillary dormant bud at each leaf axil, the upper leaves and internodes were still rapidly expanding. About nine days later, when the petals of the flower bud became visible (PCV stage), upper axillary buds had grown out into small new branches, the upper leaves and internodes were larger. Irradiance was measured with the spectrophotometer at 50 cm above the culture table, at its 4 corners in the growth chamber without plants.

• <FBV: before floral bud visible

• FBV: Floral bud visible

• FBV-PCV: between floral bud visible and petal color visible

• PCV: petal color visible

• OF: open flower

def select_experiment(manip_name="High_Light_Crop_1", stage="FBV", fill=True):
    pgl_scene = manip_named(manip_name, stage, fill) + environment()
    exp3 = PlantGL(pgl_scene, side='double')
    display(exp3)

manip_name=Dropdown(options=manips_opts_exp3, value="High_Light_Crop_1")
stage=Dropdown(options=stage_opts_exp3, value="FBV")

def update_stages(*args):
    options = experiments(manip_name.value)
    options = [o.name for o in options]
    stage.options = sorted(options)

manip_name.observe(update_stages, "value")

w = interact_manual(select_experiment, manip_name=manip_name, stage=stage, fill=Checkbox(value=False))