Cool-season grasses have developed a symbiotic relationship with Epichloë endophytes. In many environments, Epichloë
endophytes have been shown to be mutualistic symbionts of plants by
increasing the fitness of their host against abiotic or biotic stresses.
The effects of Epichloë endophytes
on other fitness-correlated plant characteristics are less intensively
studied, and the results are usually variable and contradictory. In this
study, we evaluated the effects of endophyte infection on seed
germination in Achnatherum inebrians
from four origins. Our results indicate that the germination rate of
the seeds collected from alpine regions was higher at low temperatures
than that of seeds with desert and arid grassland origins. By contrast, a
higher germination percentage was detected in seeds with desert and
arid grassland origins than in those with alpine origins in higher
temperatures. Epichloë endophyte
infection affects the cardinal temperatures of seeds from different
origins. Endophyte-infected seeds have a lower base temperature and a
higher ceiling temperature than their endophyte-free counterparts. The
value of the base temperature was higher in seeds with alpine grassland
origins than in those with desert and arid grassland origins. However,
the ceiling temperature was higher in seeds with desert and arid
grassland origins than in those with alpine grassland origins.
Consequently, future experiments should consider the effects of
endophytes on seed germination and seedling recruitment in suboptimal
climatic conditions.