title: Changing fontsize in python subplots
body: <p>I have made a phase plot of a bistable stable, with the nulclines on the main graph and have added a subplot with the trajectories overlaying it. However, no matter what I try, I cannot seem to get the x and y labels to increase in font size to 20.</p>
  
  <p>Any help would be greatly appreciated.</p>
  
  <p>Although there are similar questions, the answers to said queries don't seem to apply to this particular problem.</p>
  
  <p>Thanks again!</p>
  
  <pre><code>import numpy as np
  from scipy.integrate import odeint
  import matplotlib.pyplot as plt
  from mpl_toolkits.axes_grid.axislines import SubplotZero
  from matplotlib import pylab
  from pylab import linspace
  from numpy import meshgrid
  from numpy import hypot
  
  
  a1 = 1.0 #(Rate constant)
  g1 = 4.0 # Hill number for cdc2
  b1 = 200.0 # Rate Constant
  k1 = 30.0 #Michaelis Constant
  v =1 #coefficient that reflects the strangth of the influence of Wee1 on Cdc2
  a2 = 1.0# Rate Constant
  g2 = 4.0 #Hill number for Wee1
  b2 = 10.0 # Rate Constant
  k2 = 1.0# Michaelis constant
  
  # Function for calculating the phase plot
  def Function(u,t=0,mu=.1):
      x1 = u[0]
      y1 = u[1]
      dv = (a2* (1.0 - y1) - (b2 * y1 * x1**g2) /(k2 + (x1**g2)))                 # Model of Cdc2
      dx = (a1* (1.0 - x1) - (b1 * x1 * ((v * y1)**g1)) / (k1 + ((v*y1) **g1)))  # Model of Wee1
      return (dx,dv)
  
  t = linspace(0,1,1) #Return list from 0 to 1 in 25 intervals
  u0 = np.array([1,1]) # Creates array for odeint function 
  
  
  mu = [1,10] #call mu for 2
  for m in mu:#Get u (differentiation function )
      u = odeint(Function,u0,t,args=(m,))
  #   ax.plot(u[0:,0],u[0:,1])
  x = linspace(0,1,17) #Creates values for x
  y = linspace(0,1,18)#Creates values for y to plot
  x,y = meshgrid(x,y)# creates a grid of x by y
  X,Y = Function([x,y])# Applies funciton to grid
  M = (hypot(X,Y))# Get hypotenuse of X by Y
  X,Y = X/M, Y/M# Calculate length(strength) of arrows
  
  
  #Calculate Nulclines-----------------------------------------------------------
  
  Nulclinevalues = np.arange(0, 1+0.001, 0.001)#Calulate values to set nulcineto
  NulclineXX = []# set to an array
  NulclineYY = []#set to an array
   # Following 2 formulas show the calculation fo the nullclines
  def calcnulclineyy(xx1): 
      oa2 = 1.0#RAte constant
      og2 = 4.0 #Hill number for Wee1
      ob2 = 10.0#Rate constant
      ok2 = 1.0#Michaelis constant
      YY = (oa2*((xx1)**og2) + ok2) / (oa2*((xx1**og2)+ok2)+(ob2*(xx1**og2)))
  
  return YY
  
  
  
  def calcnulclinexx(yy1):
      oa1 = 1.0 #Rate constant 
      og1 = 4.0 # Hill number for cdc2 
      ob1 = 200.0 #Rate constant
      ok1 = 30.0#Michaelis constant
      ov = 1##coefficient that reflects the strength of the influence of Wee1 on Cdc2
      og2 = 4.0 #Hill number for Wee1
      XX = (oa1*(ok1+(ov*yy1)**og2)) / (oa1*(ok1+(ov*yy1)**og1)+ob1*(ov*yy1)**og1)
  
  return XX
  
  for YY in Nulclinevalues: 
      # print Y
      NulclineXX.append(calcnulclinexx(YY))
  
  for XX in Nulclinevalues:
      #Print X
      NulclineYY.append(calcnulclineyy(XX))
  
  
  fig = plt.figure(figsize=(6,6)) # 6x6 image
  
  ax = SubplotZero(fig,111,) #Plot arrows over figure
  
  fig.add_subplot(ax) # Plot arrows over figure
  
  # Plot both nulcines on same graph
  
  plt.axis((0,1,0,1))
  ax.set_title('v = 1',fontweight="bold", size=20) # Title
  ax.set_ylabel('Active Wee1', fontsize = 20.0) # Y label
  ax.set_xlabel('Active Cdc2-cyclin B', fontsize = 20) # X label
  plt.plot (NulclineXX,Nulclinevalues, label = " Cdc2 nulcline",c = 'r', linewidth = '2')
  plt.plot (Nulclinevalues,NulclineYY, label = "Wee1 nulcline",c = '#FF8C00', linewidth = '2')
  
  ax.quiver(x,y,X,Y,M) # plot quiver plot on graph
  ax.grid(True) # Show major ticks    
  ax.legend(handletextpad=0,loc='upper right') # Plot legend
  
  plt.show() # Show plot
  </code></pre>