Would nodal planes of participating Atomic orbitals be nodal planes of molecular orbital?
AFAIK: The nodal planes are where the wavefunction sign inverses. If you drew the colors according to the sign value then you would see that for antibonding sigma MO there is a virtual nodal plane, since the sign changes between + and - between the two centre orbital lodes. Even if they by some magic grew larger, they can never touch, they interfere destructively. There will always be a plane between them where the wavefunction returns 0. (when the two spheres meet they will form a planar interface. Imagine soap bubbles.)

I found this, it is more descriptive; https://socratic.org/questions/how-can-i-draw-antibonding-orbitals