Fix for issue #586

tripal_chado/includes/TripalFields/obi__organism/obi__organism_widget.inc

@@ -75,7 +75,7 @@ class obi__organism_widget extends ChadoFieldWidget {
       $form_state['values'][$field_name]['und'][$delta][$linker_field] = $organism_id;
     }
     else {
-      $form_state['values'][$field_name]['und'][0]['value'] = '__NULL__';
+      $form_state['values'][$field_name]['und'][0]['value'] = '';
       $form_state['values'][$field_name]['und'][$delta][$linker_field] = '__NULL__';
     }
   }

tripal_chado/includes/TripalFields/sep__protocol/sep__protocol_widget.inc

@@ -89,7 +89,7 @@ class sep__protocol_widget extends ChadoFieldWidget {
       $form_state['values'][$field_name]['und'][0]['value'] = $protocol_id;
     }
     else {
-      $form_state['values'][$field_name]['und'][0]['value'] = '__NULL__';
+      $form_state['values'][$field_name]['und'][0]['value'] = '';
       $form_state['values'][$field_name]['und'][0][$linker_field] = '__NULL__';
     }
   }