mos

[rkp52]

This crossword is getting to me now just a few clues left.
52 across not workable s---a---c-s
58 across old radio component 10 5 t-e-m----- valve?
77 across female forename e-n---e--
80 across it maintains low temperature c-y-s-a-
89 across ina fugue instances of overlapping s-r-t--
35 down deerived and maintained plant species -u---v-r
64 down across or beyond the sea t-a-------e many thanks in advance.

[Lie-in King]

52a Impractical - corrections below...
58a Thermionic valve
77a Ernestine
80a Cryostat
89a Stretti
35d Cultivar
64d Transmarine

33d Uteri
18d Procedural