The perils of pot experiments
John B. PassiouraCSIRO Plant Industry, GPO Box 1600, Canberra 2601, Australia. Email: John.Passioura@csiro.au
Functional Plant Biology 33(12) 1075-1079 https://doi.org/10.1071/FP06223
Submitted: 7 September 2006 Accepted: 2 November 2006 Published: 1 December 2006
Abstract
Experiments with plants in pots can be beset by several often-unrecognised artefacts. The soil or other medium at the bottom of a freshly watered and drained pot is inevitably saturated with water; if the pot is short the whole of the medium may have such little air-filled porosity that it becomes hypoxic. This is an especial problem with field soils used in pots, for these typically do not contain many pores large enough to be drained at the small water suctions that prevail. Such suctions are zero at the bottom of a freshly drained pot and rise by 1 kPa for every 100-mm increment in height, leading to suctions at the top of a typical pot that are much less than the 10–30 kPa that occurs in soils in the field that have drained to ‘field capacity’. Commercial potting mixes overcome this problem by using coarse materials in the mix, which create many large pores (>1 mm diameter) that drain at small suctions. Fine potting mixes used for growing Arabidopsis in small pots are likely to lead to hypoxia throughout the pot. Pots in glasshouses may experience temperatures that are substantially higher or lower than the air temperature. Sun striking the sides of dark pots can raise the temperature by several degrees. In heated glasshouses cold tap water added to warm pots can greatly affect the growth of plants in those pots. Simple precautions can at least partly ameliorate these difficulties.
Acknowledgments
I am indebted to David Bagnall, Marc Ellis, Margaret McCully, Rana Munns, and Michelle Watt for invaluable discussions.
Brockwell J, Gault RR
(1976) Effects of irrigation water temperature on growth of some legume species in glasshouses. Australian Journal of Experimental Agriculture and Animal Husbandry 16, 500–505.
| Crossref | GoogleScholarGoogle Scholar |
(verified 2 November 2006)
Pankhurst CE,
Pierret A,
Hawke BG, Kirby JM
(2002) Microbiological and chemical properties of soil associated with macropores at different depths in a red-duplex soil in NSW Australia. Plant and Soil 238, 11–20.
| Crossref | GoogleScholarGoogle Scholar |
Rasse DP, Smucker AJM
(1998) Root recolonization of previous root channels in corn and alfalfa rotations. Plant and Soil 204, 203–212.
| Crossref | GoogleScholarGoogle Scholar |
Ray JD, Sinclair TR
(1998) The effect of pot size on growth and transpiration of maize and soybean during water deficit stress. Journal of Experimental Botany 49, 1381–1386.
| Crossref | GoogleScholarGoogle Scholar |
Seki M,
Narusaka M,
Ishida J,
Nanjo T, Fujita M , et al.
(2002) Monitoring the expression profiles of 7000 Arabidopsis genes under drought, cold and high-salinity stresses using a full-length cDNA microarray. The Plant Journal 31, 279–292.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
da Silva AP,
Kay BD, Perfect E
(1994) Characterization of the least limiting water range of soils. Soil Science Society of America Journal 58, 1775–1781.
Tisdall JM,
Cockroft B, Uren NC
(1978) The stability of soil aggregates as affected by organic materials, microbial activity and physical disruption. Australian Journal of Soil Research 16, 9–17.
| Crossref | GoogleScholarGoogle Scholar |
Townend J, Dickinson AL
(1995) A comparison of rooting environments in containers of different sizes. Plant and Soil 175, 139–146.
| Crossref | GoogleScholarGoogle Scholar |
Watt M,
Kirkegaard JA, Passioura JB
(2006) Rhizosphere biology and crop productivity — a review. Australian Journal of Soil Research 44, 299–317.
| Crossref | GoogleScholarGoogle Scholar |
