Seedling with one primary leaf pair. Seedlings are less successful than mature plants in coping with stress. CAM induction cannot be elicited. Compatible solute biosynthesis is inducible by drought in cotyledons.

Juvenile plant, 3 weeks old. 3 pairs of primary leaves are visible. Juvenile plants are less able to cope with stress than mature plants & CAM induction cannot be elicited. Compatible solute biosynthesis is inducible.

Transition from juvenile to adult growth. The first side shoots are visible. CAM-inducibility coincides with this transition, side shoot emergence, and development of secondary leaves.

Adult plant 8 wks old, stressed for two weeks. Primary leaves are full size and more side shoots are present. Secondary leaves are morphologically distinct from primary leaves.

Adult plant stressed for 5 weeks. Uptake of NaCl provides a turgor gradient along the axes of the mature plant. Plant grown at less than 1 mM KCl.

Plant age is 12 weeks. The plant was stressed at 5 weeks. Size depends on the time of the start of stress and ion composition of medium. Plants grown in the presence of 4 mM KCl.

Flowering branch of a 12 week old plant. Onset of flowering is accelerated by any environmental stress, most rapidly by salt stress.

Branch with seed capsules. Only the seed capsules are viable. The rate of seed germination depends on the position of the individual seeds within the capsule. Seeds at top Germinate immediately after imbibition, seeds at the base may take > 4 weeks to germinate.

Epidermal Bladder Cells (EBC) by scanning electron microscopy of the surface of a stressed leaf. EBC are present on all tissues except the roots. They store NaCl.

EBC at the adaxial surface of an unstressed leaf.

EBC at the adaxial surface of a stressed leaf. Coloration is due to betalaine synthesis (The ice plant does not synthesize anthocyanines).

Leaf tip.
EBC are modified trichomes.

EBC in seed capsules may be one to two mm in diameter. In those we have measured up to 1.2 M NaCl.

Close-up of EBC along the stems. The elongated shape is due to limited surface area for development.

Mesembryanthemum crystallinum is a halophyte.

A major aspect of being a halophyte is the presence of EBC
- as long as there are vacuoles to be filled and EBC to expand!

It seems that one strategy for making salt-tolerant crops is to engineer the development of EBC!