Symbiotic Fungi: Principles and Practice (Soil Biology)

298 J. Álvarez-Sánchez et al.
70 C). We also calculated root/shoot ratio (R/S), leaf area ratio (LAR), specific leaf
area (SLA), net assimilation rate (NAR) and relative growth rate (RGR) (Hunt
1982):
Dry leaf weight L; g
Dry stem weight S; g
Total dry weight TDW; g
TDW=R+S+L*
Relative growth rate RGR; g g 1 day 1
RGR ¼ lnðTDW2Þ ð lnðTDW1ÞÞ
**
T2 T1
Leaf area ratio LAR; cm 2 g 1
LAR = LA/TDW ***
Specific leaf area SLA; cm 2 g 1 ; SLA = LA/L
Net assimilation rate NAR; g cm 2 day 1
NAR ¼ TDW2 TDW1
T2 T1
log LA2 log LA1
LA2 LA1
****
*R = dry root weight (this measurement was not taken into account in the field
work)
**T1 = initial day, T2 = final day.
***Where LA = leaf area; cm 2
****TDW2 and TDW1 correspond to initial total dry weight and final total dry
weight, respectively; T1 = initial day, T2 = final day; LA2 and LA1 correspond to
initial and final leaf area, respectively.
18.3.3 Results
18.3.3.1 Growth Analysis
In this chapter we present only RGR in height and biomass and survival.
In light-demanding species, mean RGRheight varied between 0.0032 and 0.0042
cm cm 1 day 1 , while shade-tolerant species varied between 0.0022 and 0.0025 cm
cm 1 day 1 (Fig. 18.2). There were significant differences between species
(p < 0.001), and the interaction soil AMF species was also significant
(p < 0.027) where Heliocarpus appendiculatus height, growing without mycorrhizae
and in tropical rain forest soil, was significantly different from the other
interactions.