Field establishment of Santalum album L. – the effect of the time of introduction of a pot host ( Alternanthera nana R. Br.)

Field establishment of the root hemi-parasite Santalum album L. under large-scale plantation conditions, until recently, has been largely unsuccessful. In this experiment, the growth of S. album seedlings grown with the herbaceous pot host Alternanthera nana R. Br. for 134, 109, 84, 60 and 35 days in a nursery container prior to field establishment was examined after 11, 16 and 23 weeks in the field. S. album survival and growth was greater, and root:shoot ratio was lower for the 23 weeks for S. album seedlings grown with A. nana compared with seedlings grown without a host. Seedlings grown with A. nana for 134 days in the nursery prior to field establishment had greater stem diameter, height and root, shoot and total plant dry weight (DW) over the 23 weeks in the field than all other treatments. Seedlings grown with A. nana for 109 days in the nursery prior to field establishment had greater field survival than all other treatments. A. nana survival in the field remained high when grown with S. album for 134 and 109 days in the nursery prior to field establishment whereas survival within remaining treatments declined significantly and A. nana growth was significantly less. S. album grown with A. nana for 134 days in the nursery prior to field establishment had a lower root:shoot ratio than all other treatments at all assessments. A strong negative linear relationship exists between S. album root:shoot ratio and A. nana DW, whereas a positive linear relationship exists between S. album DW and A. nana DW. Foliar phosphorus and sodium concentrations for S. album were lower and foliar potassium concentration higher when seedlings were grown with A. nana for 134 days in the nursery prior to field establishment compared with the remaining treatments at the 16-week assessment. The period of the S. album: A. nana association in the nursery significantly influenced S. album survival and growth following field planting.