Search Results

You are looking at 1 - 3 of 3 items for

  • Author or Editor: J. P. Bennett x
Clear All Modify Search

Abstract

Parsley (Petroselinum crispum (Mill.) Nym. cv. Banquet) incurred leaf injury, reduced growth, and altered assimilate partitioning after exposures to 20 pphm ozone. Total plant dry weight and root dry weight were decreased 23% and 43% respectively, with little effect on leaves. The relative growth rate of fumigated plants was reduced after the initial ozone exposure but leveled off at a steady state above that of the control plants when plant dry weights reached about 4.5 g. Ozone appeared to have its greatest effect on growth during initial exposures.

Open Access

Abstract

Container-grown plants of carrot (Daucus carota L.) exposed intermittently to 0.19 or 0.25 ppm ozone throughout their growth increased in plant height and total number of leaves in spite of the development of chlorotic leaves. Leaf dry weight was unaffected by ozone, but root dry matter decreased 32 to 46%. As a result, the root weight/total dry weight ratio and root/shoot ratio declined significantly in the presence of ozone. A regression of root dry weight on chlorotic leaf dry weight explained 35% of the root loss and predicted that 1.5 g of root tissue is lost for every g of chlorotic leaf dry weight caused by ozone injury.

Open Access

Abstract

Vegetative buds of trees of ‘Hardy’ and ‘Bartlett’ pears, ‘Pearmain’ apple, and ‘Sugar’ prune increased in weight steadily from their inception in spring throughout the rest period. Buds of ‘Bartlett’ grew most rapidly. Apple and prune were the slowest and grew at similar rates. In none of the species did the rest period appear to have any relation to the rate of growth. Lateral buds on trees of ‘Hardy’ during a temperature induced 4 year period of dormancy continued to grow with the formation of additional leaf primordia each year. Earlier formed primordia died and performed the function of scales. All buds of ‘Hardy’ growing in an orchard increased steadily in fresh and dry weights with no apparent effect from the rest period. The ratio of dry to fresh weight of the entire bud as well as its interior parts remained relatively constant during the period of observation.

Open Access