The first axis (39%%) indicates positive correlations among how a plant's total root length, total biomass and maximum root system breadth respond to the presence of a neighbour.
Each species consisted of a single row of data, with its mean LRR for each of the six response variables (LRR) serving as the columns: total biomass, total root length, maximum root system breadth, root : shoot ratio, horizontal asymmetry in root length and depth of maximum root system breadth.
More than 90% of the root biomass was contained within half the distance of the maximum lateral extent (5 m) and between 50 and 70% was within 1 m of the stem.
The six response variables used to describe plant responses to neighbours (total biomass, root : shoot ratio, total root length, horizontal asymmetry in root length, maximum root system breadth and depth of maximum breadth) were reduced to two main axes using PCA, explaining 68%% of the variations in the data (Fig. 4).
We found nearly 30%% of the variations in root responses to neighbours were associated with changes in biomass allocation (R : S ratio) and fine-scale changes in root placement (horizontal asymmetry and depth of maximum root system breadth), rather overall size.
Root length, root area, number of root furcation, and root biomass of C. dactylon plants increased significantly with the increase of altitude (P < 0.05) and reached the maximum at an altitude of 175 m.
belowground root biomass ratio.
a: Leaf biomass (g), b: Shoot biomass (g), c: Root biomass (g), d: Total biomass (g).
Root length and root biomass were obtained for individual seedlings.
Root biomass was more severely inhibited than shoot biomass and Cu was mainly retained in roots.
