Plant phenometrics systems and methods and devices related thereto
Chlorophyll fluorescence may be studied in response to a variety of environmental cues or conditions by growing phototrophic organisms under actinic illumination. Such illumination may be punctuated or disrupted to gain information about the photosynthetic properties or performance of the phototrophic organism. Instruments or devices for carrying out the method are also described.
1. A method of measuring a photosynthetic parameter comprising:
illuminating a phototrophic organism with actinic illumination;
switching off the actinic illumination for a period that minimizes perturbations to photosynthesis;
pulsing the phototrophic organism with a measuring light during the period when the actinic illumination is switched off;
collecting chlorophyll fluorescence data within the period when the actinic illumination is switched off; and
determining a photosynthetic parameter from the fluorescence data.
2. The method of claim 1 wherein the actinic illumination comprises white spectrum in the range of about 380 nm to about 750 nm.
3. The method of claim 1 wherein the illuminating comprises light intensities in excess of about 2,500 micro moles photon m −2 s −1 , at a distance of about 0.5 meters or greater.
4. The method of claim 1 wherein the actinic illumination is switched off for about 100 to about 120 microseconds.
5. The method of claim 1 wherein the pulsing is by a monochromatic light.
6. The method of claim 1 wherein the pulsing is light in the visible spectrum (400-700 nm).
7. The method of claim 1 wherein the pulsing is for about 1 to about 50 microseconds.
8. The method of claim 1 wherein the pulsing is a series of measuring pulses.
9. The method of claim 8 wherein the pulsing comprises from 1 to about 100 measuring pulses.
10. The method of claim 1 wherein the collecting is about 5 to about 50 microseconds within switching off the actinic illumination.
11. The method of claim 1 further comprising providing a saturating actinic flash with intensity in excess of about 20,000 micro moles m −2 s −1 .
12. The method of claim 1 wherein the phototropic organism comprises whole plants, plant parts, tissue culture and/or cell suspensions.
13. The method of claim 1 wherein the chlorophyll fluorescence data is used to determine a physiological state of the phototrophic organism.
14. The method of claim 1 further comprises collecting and evaluating the data in response to environmental conditions selected from carbon dioxide, light intensity, light wavelength, light duration, water, nutrient content and combinations thereof.
15. The method of claim 1 wherein when the actinic illumination is switched off, the infrared spectral contamination of the chlorophyll fluorescence by the actinic illumination is minimized.
16. The method of claim 1 wherein the method is a continuous method of measuring multiple phototropic organisms.
17. The method of claim 1 wherein the measuring occurs over a period of days or weeks.
18. A system for measuring a photosynthetic parameter of a phototrophic organism comprising:
an actinic light source and a measuring light source;
a sensor for capturing chlorophyll fluorescent data on the phototrophic organism; and
one or more processing units capable of switching the actinic and measuring light sources on and off in a manner which allows the phototrophic organism to be pulsed with the measuring light source during a period when the actinic light source is switched off, wherein the duration of the period when the actinic light source is switched off is short enough to minimize perturbations to photosynthesis.
19. The system of claim 18 adapted for use in a growth chamber or a green house.
20. The system of claim 18 wherein the actinic light is a white light emitting diode.
21. The system of claim 18 wherein the actinic light comprises light intensities in excess of about 2500 micro moles photon m −2 s −1 , at a distance of about 0.5 meters or greater.
22. The system of claim 18 wherein the measuring light source is a monochromatic light.
23. The system of claim 18 further adapted to be portable.
24. The system of claim 18 , wherein the period when the actinic light source is switched off is from about 100 microseconds to about 120 microseconds.
25. The system of claim 18 wherein the actinic light source is capable of providing a wavelength from about 380 to about 750 nm.
26. The system of claim 18 wherein the unit is capable of pulsing the measuring light source for about 1 to about 50 microseconds.
27. The system of claim 18 wherein the unit is capable of pulsing the measuring light source from 1 to about 100 times.