Results
Tiller number and plant biomass
Tiller number was significantly greater in Monkhead compared with 92-46,
but tiller number generally increased in high fertility irrespective of
variety (Table 1, Fig. 2a). Increase of tiller number in response to
fertilizer addition was more in Monkhead compared with 92-46
(significant Variety × Fertility interaction, Table 1, Fig. 2a). Root
biomass and stem&leaf biomass were greater in Monkhead (Table 1, Fig.
2b-c), but there was no significant difference in seed biomass between
the two wheat varieties (Table 1, Fig. 2d). Fertilizer addition
increased plant biomass in all plant components (Table 1, Fig. 2). Root
and stem&leaf biomass responses to fertility differed between the two
varieties (significant Variety × Fertility interaction, Table 1), with
Monkhead showing more pronounced responses to high fertility compared
with 92-46 (Fig. 2b-c). We did not detect significant interactions
between variety and fertility for seed biomass (Table 1, Fig. 2d). There
were no significant effects of partition treatments on tiller number or
biomass, and we did not detect significant Variety × Partition
interactions, Fertility × Partition interactions or Variety × Fertility
× Partition interactions (Table 1).
Allometric relationships
We found significant linear relationships between whole plant biomass
and reproductive or non-reproductive components across treatments (Table
2). In root-total relationships, the slope and intercept were similar
between Monkhead and 92-46 at either fertility level (Table 2, Fig.
3a-b). Fertilizer addition did not affect the slope but lower the
intercept for both varieties (Table 2, Fig. 3a-b). In (stem+leaf)-total
relationships, the slope was similar between the two varieties whilst
the intercept for Monkhead was greater than that of 92-46 at either
fertility level (Table 2, Fig. 3c-d). Fertilizer addition did not affect
the slope for both varieties and the intercept for 92-46, but increased
the intercept for Monkhead (Table 2, Fig. 3c-d). In seed-total
relationships, the slope for Monkhead was greater than that of 92-46
whilst the intercept was lower at either fertility level (Table 2, Fig.
3e-f). Fertilizer addition did not affect the slope for both varieties
and the intercept for 92-46, but decreased the intercept for Monkhead
(Table 2, Fig. 3e-f).
In all 24 allometic comparisons (both slopes and intercepts) between
mesh partition and plastic partition, only 4 showed small differences in
slope or intercepts, and all of them were in low fertility treatments
(Table 3, Appendix 1 and 2 ). For Monkhead in low fertility treatments,
the intercept in seed-total biomass regression was lower in mesh
partition than in plastic partition, whilst in (stem+leaf)-total biomass
regression was greater (Table 3, Appendix 1c and e). For 92-46 in low
fertility treatments, the slope in root-total biomass regression was
greater in mesh partition whilst the intercept was lower (Table 3,
Appendix 1b).