Sturgeon has says the English and Scottish governments would negotiate pension liabilities at the point of independence but other senior members of her party have given different views on how this will be handled. The Blueprint for Scottish Independence, which was written before the 2014 referendum, said after independence the responsibility for paying out to Scottish pensioners would be held by the Scottish Government.
There are assets and liabilities, including pensions, that of course will be subject to negotiation when Scotland becomes independent. On an ongoing basis it will be for the Scottish Government to fund Scottish pensions, but in terms of how we take account of historic assets and liabilities, that will be a matter of negotiation.
In response to the argument that pensions are paid out of current taxes rather than out of national insurance contributions:
You might want to look at the Fraser of Allander comments on this just recently when they talk about the fact that access to pensions in the UK is not based on citizenship, it is based on National Insurance contributions.