finding data trends

I have a dataset that includes four replicates of 7 different concentrations of pesticides applied to a plant. After exposure the number of offshoots was recorded (ranged from 0-7) and the lengthwise growth. (1) How do I go about describing trends at a significance level of P=0.05. I have already described the central tendency and variability of the data for each concentration. (2) How do I show which concentrations are significantly different (P=0.05) from the 4 control samples which had no chemical added?
I think that the data is generated from either Completely Randomised Design or Completelly randomised block design with plotwise observations recorded at regular intervals of time period. Such data can be properly analysed as Multi observation Data from designed experiments.

You may consult, ' Statistical Procedures in Agricultural Reserach" by Gomez and Gomez a John Wiley Publication for complete guidelines to analyse such experimental data.

Wish you best of luck
Dr N S Gandhi Prasad
Retd. Professor of Agril. Statisitics
Carry out 2 way ANOVA twice with factor 1 = sample
factor 2 = concentration level
Measured variable 1 = lengthwise growth
2 = no. of offshoots.