Table 3.

Hydraulic conductance [(m³ s⁻¹ MPa⁻¹)×10⁻¹²] and conductivity [(m s⁻¹ MPa⁻¹)×10⁻⁸] of individual seminal and adventitious roots of hydroponically grown barley plants

Hydraulic parameter	Root	Hydrostatically induced water flow			Osmotically induced water flow
		Root pressure probe	Vacuum perfusion	Mean (range)	Root pressure probe	Vacuum perfusion	Exudation	Mean (range)
Conductance	Seminal	65±30a,b,c	94±17a,b	80 (65–94)	27±11de	119±52b	61±11a,b	69 (27–119)
	Adventitious	15±6.8d	–	15	10±6.8d,f	–	6.2±1.8f	8.1 (6.2–10)
Conductivity	Seminal	13±2.6a,b	20±3.6d	16.5 (13–20)	5.4±2.0c	25±10b,d	12±1.8a	14 (5.4–25)
	Adventitious	10±5.1a,b,c	–	10	6.3±3.4a,c	–	5.1±0.5c	5.7 (5.1–6.3)

Values for each method are given as means ± SD of three roots; the range of values is given in brackets ‘(min–max)’, together with the overall mean.

Statistical significance of difference in conductance or conductivity between types of root, experimental approach, and hydrostatically and osmotically induced water flow is indicated by different superscripts (P≤0.05, Student's t-test). ‘–’, values obtained for adventitious roots through the vacuum-perfusion set-up suffered from high variation between replicate analyses, suspect to artefacts, and were not considered.