function plant_model(gamma,alpha,beta,sigma,s00,n)
p=zeros(1,n+1);
s0=p;
s1=p;
s2=p;
p(1)=0;s0(1)=s00;s1(1)=0;s2(1)=0;
for k=1:n
   s1(k+1)=sigma*s0(k);
   s2(k+1)=sigma*(1-alpha)*s1(k);
   p(k+1)=alpha*s1(k+1)+beta*s2(k+1);
   s0(k+1)=gamma*p(k+1);
end
figure(1)
clf
subplot(2,2,1)
plot([0:n],p)
title('Plants');xlabel('generations')
subplot(2,2,2)
plot([0:n],s0)
title('New Seeds');xlabel('generations')
subplot(2,2,3)
plot([0:n],s1)
title('One year old seeds');xlabel('generations')
subplot(2,2,4)
plot([0:n],s2)
title('Two year old seeds');xlabel('generations')