The Effect of Environmental Parameters on the Germination, Growth, and Development of Suaeda Depressa (Pursh) Wats

Abstract

A study was made to determine the effect of environmental parameters on the germination, growth, and development of Suaeda depressa (Pursh) Wats. Germination tests showed that seeds germinated in solutions containing up to 4 % NaCl with no toxic effects indicated after treatment with distilled water. The rate of germination and the percentage germination decreased with increased salinity. The effect of environmental parameters on growth was measured by shoot height, side shoot development, leaf length, and dry weight. Growth was greatest in 1 % NaCl solutions with adequate available nitrogen. With increased salinity and low available nitrogen levels plant growth decreased. A 10‐hr photoperiod stimulated immediate floral induction. Although flowering and completion of the life cycle occurred in solutions containing up to 4 % NaCl, increased salinity decreased the rate of floral induction and the dry weight of flowers and fruit produced. This study indicates that environmental parameters such as salinity, available nitrogen, and photoperiod can create a variety of growth forms, causing taxonomic confusion.

Influence of salinity on germination and seeds viability of two primary colonizers of Mediterranean salt pans

“…Nevertheless, the effect of an increase in salinity on the germination of both species was different. Germination under 1% of salinity is very high for S. ramosissima (between 94% and 99%), much greater than obtained by Keiffer & Ungar (1997) for Salicornia europea and Williams & Ungar (1972) for Suaeda depressa and similar to those obtained from other halophyte species such as Atriplex prostata and Suaeda calceoliformis (Keiffer & Ungar, 1997). However, germination rates for A. macrostachyum (26% and 27%) were lower than those of S. ramosissima in this study and for Arthrocnemum halocnemoides (Malcolm, 1964).…”

“…At salinity over 1%, S. ramosissima germination decreased significantly (81%). These values are high compared to those obtained for other species such as S. europea (41%) (Keiffer & Ungar, 1997) and other halophytes such as S. depressa (7%) (Williams & Ungar, 1972). But germination of A. macrostachyum (24%) did not decrease significantly, which indicates that an increase of salinity to that threshold (3%) does not affect significantly its germination and that Arthrocnemum could be better adapted to the extreme environmental conditions of Mediterranean climate high salt marshes.…”

“…In autumn, with greater rainfall and decrease in salinity, environment factors favour that dormancy is interrupted and germination takes place (Vleeshouwers et al, 1995). This illustrates that exposure to high salinity does not harm seeds of halophyte species (Williams & Ungar, 1972;Rozema, 1975;Osborne et al, 1993;Keiffer & Ungar, 1997). Heydecker et al (1973) described how a pre-exposure to high salinity speeded up germination and increased germination rates in seeds of many species when they were removed away from the saline solution, increasing their water content.…”

The effect of salinity on the growth, water status, and ion content of a leaf succulent perennial halophyte, Suaeda fruticosa (L.) Forssk

“…Growth stimulation by salinity has been reported in annual species of Suaeda but no data are available for the perennial salt desert species Suaeda fruticosa (L.) Forssk. (Williams & Ungar, 1972;Boucaud & Ungar, 1978;Ke-Fu et al, 1995).…”

Efeitos dos estresses hidrico e salino e da ação de giberelina em sementes de <i>Senna spectabilis. </i>

“…Provavelmente, as glicófilas não apresentam essa resposta de recuperação, uma vez que o NaCl produz efeito tóxico, além do osmótico. Porém, nas halófilas o efeito dos sais é principalmente osmótico e, nessa categoria de plantas, a resposta de recuperação está sempre presente (WILLIAN & UNGAR, 1972).…”