A desert planet with temperate polar regions could sustain how much plant-life? Any?

One proposed type of desert planet is one in which the equator and the "tropics" are harsh, hot deserts, but the polar regions are temperate, habitable, and lush with life.
You can see an example of this in the video game "Homeworld": the planet Kharak.

My question is, assuming that such a planet had an atmosphere similar to Earth, and an axial tilt and day/year length similar to Earth, would it be possible for plant life to survive at the poles?

The reason I doubt that this is possible is that the amount sunlight you receive is dependent on the angle of the sunlight, and the angle of sunlight near the poles is always extreme.
Also, the polar regions would experience nights that are months long.
I've read that photosynthesis is not very efficient (see Photosynthetic efficiency).
Would plants be able to get enough energy from sunlight to sustain themselves? And if so, would it be enough to support a full food chain?

posted over 4 years ago

cowlinator‭

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