Reproductive allocation and fruit-set pattern in the euhalophyte Suaeda salsa in controlled and field conditions

Reproductive allocation and fruit-set pattern are important characteristics of halophytes, and these characteristics were investigated in euhalophyte Suaeda salsa (S. salsa). The plants comprised of those treated with 1mM (control) or 500mM (high salinity) of NaCl for 120days in a glasshouse and those collected in the field. In controlled conditions, high salinity increased reproductive allocation and the number of fruits and seeds in each node of the branches. In field conditions, reproductive allocation and the number of fruits and brown seeds in S. salsa at the upper tide line were higher than at the lower tide line. There were more fruits and seeds distributed in the central part than those in the base or top of branches in both controlled and field conditions. Soil organic matter, total nitrogen and total phosphorus content at the upper tide line were lower than at the lower tide line. An opposite trend could be observed in the total soluble salt, Na+ and Cl- content in soil. In conclusion, the fruit-set pattern of S. salsa may be affected by both resource constraints and resource allocation. Reproductive allocation and fruit-set pattern may ensure the establishment of S. salsa in high saline and low nutrient environments.