To explore the effects of drought and salt stress on germination characteristics of halophytes, this study simulated drought stress with different concentrations of PEG-6000 and four sodium salts (NaCl, Na2SO4, NaHCO3, Na2CO3) to evaluate the effects of those treatments on the seed germination characteristics of Halogeton glomeratus. It was found the germination percentage and germination energy decreased with increasing PEG-6000 concentration, while the seedling fresh weight, dry weight, plant height and root activity initially increased and then decreased at higher PEG-6000 concentration. Cluster analysis and principal component analysis showed that the different PEG-6000 concentrations could be divided into two groups with 6% PEG-6000 as the point of separation. Fresh weight appeared to be an important parameter. In addition, germination percentage germination energy, seedling fresh weight, dry weight, plant height and root activity declined with increase in concentration of the four sodium salts. This indicated that salt stress inhibited seed germination and seedling growth, with the effects of the four tested sodium salts ranked: Na2CO3>NaHCO3>NaCl>Na2SO4. Cluster analysis and principal component analysis showed that the sodium salt concentrations were divided into two groups with the separation points falling at 50.00 mmol·L-1 NaHCO3, 62.50 mmol·L-1 Na2SO4, 25.00 mmol·L-1 Na2CO3 and 100.00 mmol·L-1 NaCl. Among the plant traits evaluated as indicators of H. glomeratus stress tolerance in the germination stage, the germination index was the key indicator of NaHCO3 and Na2SO4 stress, root activity emerged as the primary indicator of Na2CO3 stress and dry weight was the major indicator of NaCl stress in H. glomeratus.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |