Rmb. Stoltzfus et al., EFFECT OF INCREASING ROOT-ZONE TEMPERATURE ON GROWTH AND NUTRIENT-UPTAKE BY GOLD-STAR MUSKMELON PLANTS, Journal of plant nutrition, 21(2), 1998, pp. 321-328
Growth response of plants to root-zone temperature (RZT) varies with s
pecies. We studied the effects of RZT on muskmelons (Cucumis melo L. '
Gold Star') held continuously at 25 degrees, 30 degrees, 35 degrees, 4
0 degrees, and 45 degrees C in a nutrient solution bath for 12 days. M
uskmelon seedling sizes used were the first and fourth leaf growth sta
ges. Large seedling size growth rate was approximately double that of
the small size. Plant fresh weight gain for large plants was highest a
t the 25 degrees C RZT, while for small plants fresh weight gain was s
imilar from 25 to 35 degrees C. But dry weight gain was similar for bo
th plant sizes from 25 to 35 degrees C. Root-zone temperatures >35 deg
rees C resulted in a sharp linear decrease in fresh weight, dry weight
, and leaf number. Shoot elemental phosphorus (P), zinc (Zn), and mang
anese (Mn) content and concentration followed the same pattern as grow
th. Root P and Zn concentration increased linearly with increasing RZT
, but Mn concentration reached a maximum at 35 degrees C. The RZT thre
shold for optimum muskmelon seedling growth seems to be 35 to 36 degre
es C.