BackgroundRecent advances in genome sequencing technologies have shifted the research bottleneck in plant sciences from genotyping to phenotyping. This shift has driven the development of phenomics, high-throughput non-invasive phenotyping technologies.ResultsWe describe an automated high-throughput phenotyping platform, the Phenovator, capable of screening 1440 Arabidopsis plants multiple times per day for photosynthesis, growth and spectral reflectance at eight wavelengths. Using this unprecedented phenotyping capacity, we have been able to detect significant genetic differences between Arabidopsis accessions for all traits measured, across both temporal and environmental scales. The high frequency of measurement allowed us to observe that heritability was not only trait specific, but for some traits was also time specific.ConclusionsSuch continuous real-time non-destructive phenotyping will allow detailed genetic and physiological investigations of the kinetics of plant homeostasis and development. The success and ultimate outcome of a breeding program will depend greatly on the genetic variance which is sampled. Our observation of temporal fluctuations in trait heritability shows that the moment of measurement can have lasting consequences. Ultimately such phenomic level technologies will provide more dynamic insights into plant physiology, and the necessary data for the omics revolution to reach its full potential.Electronic supplementary materialThe online version of this article (doi:10.1186/s13007-016-0113-y) contains supplementary material, which is available to authorized users.

A method is proposed for assessing the maturity and quality of seeds, based on measuring the amount of chlorophyll fluorescence (CF) signals of intact seeds. In general, the amount of chlorophyll is directly related to the degreening process and thus the maturity. Cabbage seeds (Brassica oleracea var. capitata) were separated into three subsamples based on the CF signals of the individual intact seeds. Seeds with the lowest amount of CF had the highest percentage of germination and normal seedlings. In a controlled deterioration test, the subsample with the lowest CF signal had slightly lower germination and normal seedling percentages than the non-treated seeds, whereas the seeds with the highest CF signals had much lower germination and normal seedling percentages. Advantages of the CF method for determining seed maturity and seed quality are its high sensitivity and fully non-destructive nature and the high speed at which the fluorescence is generated and measured.

Chlorophyll fluorescence of the testa of seeds is proposed as a non-invasive method for the determination of maturity and quality of seeds. In this study cabbage seeds (Brassica oleracea) were sorted individually based on the chlorophyll fluorescence signals into four subsamples labeled with respect to their chlorophyll fluorescence signal (low, medium, high and very high). The results show that the magnitude of the chlorophyll fluorescence signal was inversely related to the quality of the seeds, expressed as germination %, normal seedling %, germination rate (T50) and uniformity of germination (T75-T25). The seed lot could be improved from 90 to 97% normal seedlings by sorting out 13% of the seeds with very high chlorophyll fluorescence signals. Advantages of the chlorophyll fluorescence method for sorting seeds are the high sensitivity, the method being fully non-destructive, the high speed at which the fluorescence is generated and measured and the specificity for only chlorophyll. Other pigments or substances which can influence seed colour but do not fluoresce at the specific wavelengths of excitation and emission of chlorophyll, will not contribute to the fluorescence signal. These characteristics make chlorophyll fluorescence highly suitable as a new sorting technique.

Studies based on X-ray photographs were conducted to predict the morphology of tomato (Lycopersicon esculentum Mill.) seedlings at transplanting stage. Currently, seed-lot quality of tomato seeds for growing commercial transplants is determined with grow-out tests in the greenhouse because the standard germination test fails to predict the percentage of normal or usable transplants (UTs). These grow-out tests, however, are difficult to standardize. An X-ray evaluation procedure is presented as an alternative. X-ray images nondestructively provide information on embryo size and morphology and the amount of endosperm and the area of free space. These parameters correlate well with the morphology of 14-day old seedlings. Cotyledon morphology has the highest correlation with the percentage of UTs. A test based on the evaluation of X-ray images, classifying the cotyledon morphology and seed free space, predicts the percentage of UTs more accurately than the currently used germination test. A second method based on an equation that uses the probabilities of all X-ray categories proportionally predicts the percentage of UTs of primed seeds more accurately than the first method. Selecting individual seeds based on X-ray images has the potential to raise the percentage of UTs of seed lots. On the average, the percentage of UTs of control seeds was 22% higher after hand selection based on X-ray evaluation. Primed seeds gave 12% higher results. Hence, X-ray analysis can predict seedling performance and enable the selection of high-quality seeds.

Morphological changes in tomato (Lycopersicon esculentum Mill. cv. Moneymaker) seed during osmopriming and imbibition (‘hydropriming’) were followed using X-ray photographs. Embryo, endosperm and free space areas were measured. Both osmopriming and hydropriming resulted in free space development (+ 8.1% and + 10.8% of the whole seed planar area, respectively), almost all at the cost of the endosperm area. Planar dimensions of whole seeds were relatively constant and the dimension perpendicular to the planar surface, the thickness, could account for the volume increase of primed seeds reported in the literature. In dead seeds, only a small amount of free space developed while the planar area of the seed remained the same. In the imbibing viable seeds no deterioration of endosperm could be detected until the moment of root protrusion.Seeds which were osmoprimed directly after harvest, i.e. in the fresh state, did not showthe induction of any free space, while free space developed normally after dehydration and a second priming treatment. Apparently, a dehydration step prior to the priming treatments is required for the development of free space in osmo- or hydroprimed seed.X-ray photographs of hydroprimed seeds showed that the radicle tip adhered tightly to theendosperm cap. This results in various forms of damage to the root tips upon redrying. Priming did not introduce cotyledon abnormalities.