Chapter 3 - Gaining water and nutrients: root function

  • strict warning: Non-static method view::load() should not be called statically in /var/www/pia/drupal/sites/all/modules/views/views.module on line 906.
  • strict warning: Declaration of views_handler_argument::init() should be compatible with views_handler::init(&$view, $options) in /var/www/pia/drupal/sites/all/modules/views/handlers/views_handler_argument.inc on line 744.
  • strict warning: Declaration of views_handler_filter::options_validate() should be compatible with views_handler::options_validate($form, &$form_state) in /var/www/pia/drupal/sites/all/modules/views/handlers/views_handler_filter.inc on line 607.
  • strict warning: Declaration of views_handler_filter::options_submit() should be compatible with views_handler::options_submit($form, &$form_state) in /var/www/pia/drupal/sites/all/modules/views/handlers/views_handler_filter.inc on line 607.
  • strict warning: Declaration of views_handler_filter_boolean_operator::value_validate() should be compatible with views_handler_filter::value_validate($form, &$form_state) in /var/www/pia/drupal/sites/all/modules/views/handlers/views_handler_filter_boolean_operator.inc on line 159.
  • strict warning: Declaration of views_plugin_style_default::options() should be compatible with views_object::options() in /var/www/pia/drupal/sites/all/modules/views/plugins/views_plugin_style_default.inc on line 24.
  • strict warning: Declaration of views_plugin_row::options_validate() should be compatible with views_plugin::options_validate(&$form, &$form_state) in /var/www/pia/drupal/sites/all/modules/views/plugins/views_plugin_row.inc on line 134.
  • strict warning: Declaration of views_plugin_row::options_submit() should be compatible with views_plugin::options_submit(&$form, &$form_state) in /var/www/pia/drupal/sites/all/modules/views/plugins/views_plugin_row.inc on line 134.
  • strict warning: Only variables should be passed by reference in /var/www/pia/drupal/modules/book/book.module on line 559.
Printer-friendly version

figure

Seedlings of Eucalyptus globulus which have formed an ectomycorrhizal association with the fungus Hebeloma, whose white mycelium can be seen ramifying through the soil and forming basidiomes (toad-stools) above the soil (Photograph courtesy I. Tommerup, CSIRO Forestry and Forest Products)

A radicle may be compared with a burrowing mole, which wishes to penetrate perpendicularly into the ground. By continually moving its head from side to side, or circumnutating, he will feel a stone or other obstacle as well as any difference in the hardness of the soil, and he will turn from that side; if the earth is damper on one than the other side he will turn thitherward as a better hunting-ground. Nevertheless, after each interruption, guided by the sense of gravity, he will be able to recover his downward course and burrow to a greater depth.

(Charles Darwin, The Power of Movement in Plants, 1881).

»