Skip to main content

Table 2 Experimental and coded levels used in central composite design for studying the effects of protoplast concentration (x1), total plasmid DNA (X2), and endosperm age (x3) on protoplast transfection efficiency along with the predicted mean and observed responses

From: Optimization of isolation and transfection conditions of maize endosperm protoplasts

Experimental factor Coded symbol Coded variable levels
   Lowest Low Centre High Highest   
   -α (−1.68) −1 0 +1 +α (+1.68)   
Protoplast Conc. (× 106) cells/ml X1 0.5 1.0 1.5 2.0 2.5   
Total plasmid DNA (µg) X2 5 7 10 13 15   
Endosperm age (DAP) X3 6 7 8 9 10   
Test number Coded levels Actual levels Response
Transfection efficiency, Y1 (%)
X1 X2 X3 X1 X2 X3 Observed Y1 Predicted Y1
Coded levels for the three factors selected for protoplast transfection
1 +1 +1 +1 2 13 9 35.0 35.1
2 +1 +1 −1 2 13 7 44.6 43.2
3 +1 −1 +1 2 7 9 38.3 37.1
4 +1 −1 −1 2 7 7 34.3 36.9
5 −1 +1 +1 1 13 9 30.6 31.3
6 −1 +1 −1 1 13 7 37.4 41.5
7 −1 −1 +1 1 7 9 27.7 33.5
8 −1 −1 −1 1 7 7 31.5 34.9
9 +1.68 0 0 2.5 10 8 43.8 45.2
10 −1.68 0 0 0.5 10 8 46.4 41.3
11 0 +1.68 0 1.5 15 8 43.5 43.0
12 0 −1.68 0 1.5 5 8 42.9 39.4
13 0 0 +1.68 1.5 10 10 28.1 26.6
14 0 0 −1.68 1.5 10 6 39.6 36.3
15 0 0 0 1.5 10 8 64.3 64.8
16 0 0 0 1.5 10 8 63.3 64.8
17 0 0 0 1.5 10 8 68.4 64.8
18 0 0 0 1.5 10 8 66.2 64.8
19 0 0 0 1.5 10 8 64.4 64.8
20 0 0 0 1.5 10 8 65.1 64.8
21 0 0 0 1.5 10 8 64.2 64.8
22 0 0 0 1.5 10 8 59.6 64.8
23 0 0 0 1.5 10 8 66.7 64.8