Pampered inside, pestered outside? Differences and similarities between plants growing in controlled conditions and in the field

Abstract

Summary: Plant biologists often grow plants in growth chambers or glasshouses with the ultimate aim to understand or improve plant performance in the field. What is often overlooked is how results from controlled conditions translate back to field situations. A meta‐analysis showed that lab‐grown plants had faster growth rates, higher nitrogen concentrations and different morphology. They remained smaller, however, because the lab plants had grown for a much shorter time. We compared glasshouse and growth chamber conditions with those in the field and found that the ratio between the daily amount of light and daily temperature (photothermal ratio) was consistently lower under controlled conditions. This may strongly affect a plant's source : sink ratio and hence its overall morphology and physiology. Plants in the field also grow at higher plant densities. A second meta‐analysis showed that a doubling in density leads on average to 34% smaller plants with strong negative effects on tiller or side‐shoot formation but little effect on plant height. We found the r2 between lab and field phenotypic data to be rather modest (0.26). Based on these insights, we discuss various alternatives to facilitate the translation from lab results to the field, including several options to apply growth regimes closer to field conditions. Contents Summary I. Introduction 839 II. Phenotypic differences between lab‐ and field‐grown plants 839 III. The shoot environment 841 IV. The root environment 845 V. Effects of plant density 847 VI. Consistency among species or genotypes in ranking between lab and field 848 VII. Translation of lab results to the field 849 VIII. Conclusions 851 Acknowledgements 851 Author contributions 852 References 852 Appendix A1 854