Hardy Experiments

• Hardy
• Frost
• Thaw

Hardy

Researcher

Jiwan P Palta & Laurie S Weiss, U WI Horticulture

Description

Scientists in horticulture have been interested in how plants adapt to cold climates such as we find in Wisconsin. They have noticed that plants which have been previously `acclimatized' suffer less damage. Palta and Weiss (1993) conducted a controlled laboratory experiment to examine two species of potatoes (1, 2) subjecting plants to one of two acclimatization regimes (1 kept in cold room; 0 kept at room temperature) for several days. Plants were later subjected to one of two cold temperature treatments (1 just below freezing, -4 C; 2 way below freezing, -8 C). Two responses were measured, both being damage scores for photosynthesis and ion leakage. Initially there were 80 plants, but some were lost during the experiment. Your analysis should take care to address the imbalance due to unequal sample sizes for the different factor combinations.

Reference

Palta JP and Weiss LS (1993) `Ice formation and freezing injury: an overview on the survival mechanisms and molecular aspects of injury and cold acclimation in herbaceous plants', in Advances in Plant Cold Hardiness, ed. by PH Li and L Christersson. CRC Press, Boca Raton, LA.

Data & Setup

hardyraw.dat

potato regime temp protein lipid

hardyraw.sas

create code; sqrt transform of lipid

hardy.dat

potato regime temp code protein lipid

hardy.s

read data, analysis of variance, analysis of covariance

hardy.snk

results from hardy.s

SAS Data Analysis

hardyplot.s

various diagnostic and interaction plots

hardy.sas

read data, analysis of variance, analysis of covariance

Frost

Data & Setup

frost.dat

catrt accn hardy rep y frost sps

SAS Data Analysis

frost.sas

read data, analysis of variance, analysis of covariance

nesting within accessions

Thaw

Data & Setup

thawall.dat

ex per acc temp run ilc ilt chlc chlt ruc rut rchlc rchlt puc put

thawall.sas

combine measurements to get thaw data

thaw.dat

regime temp ion photo

SAS Data Analysis

thaw.s

read data, analysis of variance, analysis of covariance