This should get you started (note that I named the variable out rather than Plot, as it is bad practice to use names which only differ in character-case from an existing function/variable name):
>> [~,~,raw] = xlsread('test.xlsx');
>> fld = regexp(raw(2:end,1),'(?<=^Plot\.)\w+$','once','match');
>> out = cell2struct(raw(2:end,2),fld,1)
Note that the order of the fields in the file is irrelevant:
Note that you can easily add checks on the Plot name/field/data, as required, or allow for names other than Plot. Ask if you want help with any of this!