Weed life history: identifying vulnerabilities - Ecological Management of Agricultural Weeds - page 64

Table 2.7. Seed size and growth parameters for some weeds and crops

Seed weight RGR NAR LAR SLA LWR RWR Root diameter RLI

Species (mg) (g g 1 d 1 ) a (g dm 2 d 1 ) b (cm 2 g 1 ) c (cm 2 g 1 ) d (g g 1 ) e (g g 1 ) f (mm) g (cm cm 1 d 1 ) h

Amaranthus reroflexus 0.41 0.349 0.298 198 326 0.597 0.189 0.22 0.343

Chenopodium album 0.44 0.335 0.254 224 329 0.674 0.153 0.20 0.285

Abutilon theophrasti 7.8 0.244 0.145 190 326 0.583 0.214 0.46 0.274

Xanthium strumarium 38 0.187 0.224 136 237 0.560 0.217 0.35 0.227

Sunflower (domestic) 61 0.197 0.241 140 276 0.495 0.272 0.42 0.227

Soybean 158 0.155 0.176 132 242 0.539 0.241 0.64 0.201

Correlation with -0.99** -0.59 -0.94** -0.86* -0.84* 0.86* 0.86* -0.93**

ln (seed weight)

Notes:
a RGR: relative growth rate

g increase in plant weight g 1 plant weight d 1 .
b NAR: net assimilation rate g increase in plant weight dm 2 leafarea d 1 .
c LAR: leafarea ratio

cm 2 leafarea g 1 plant weight.
d SLA: specific leafarea cm 2 leafarea g 1 leafweight.
e LWR: leafweight ratio

g leafweight g 1 plant weight.
f RWR: root weight ratio g root weight g 1 plant weight.
g Average ofroot diameters at 0,7,14,21,and 28 days after emergence.
h RLI: relative rate ofroot length increase from 0 to 28 days after emergence.
* Significant at p

0.05 level.
** Significant at p 0.01 level.
Source : From Seibert & Pearce (1993)