The effects of acid rain and ozone on biomass and leaf area parameters of shortleaf pine (Pinus echinata Mill.)

Shortleaf pine (Pinus echinata Mill.) seedlings in 24 open-top chambers were exposed to combinations of ozone (carbon-filtered (control), ambient, 1.7 x ambient, and 2.5 x ambient) and acidic precipitation (pH 5.3, 4.3 and 3.3) for 16 months (1989 harvest) or 28 months (1990 harvest). Although the effects of acid rain were generally not significant, there was a trend toward increased aboveground biomass and leaf area in seedlings subjected to the low pH treatments. Because N concentrations in the soils generally increased with decreasing pH, we concluded that the effects of acid rain on aboveground biomass and leaf area were a consequence of an increasing concentration of soil N. In the 1989 harvest, seedlings in the 2.5 x ambient ozone treatment had significantly less biomass in all aboveground plant components and significantly less total leaf area than seedlings in the 1.7 x ambient ozone treatment. In the 1990 harvest, there were no significant effects of ozone on total aboveground biomass, although there was a trend toward reduced biomass in seedlings in the 2.5 x ambient ozone treatment. Both total leaf area and leaf biomass were significantly less in seedlings exposed to 2.5 x ambient ozone for 28 months than in both control seedlings and seedlings in the 1.7 x ambient ozone treatment. The greater, but not always significant, aboveground biomass and leaf area of seedlings in the 1.7 x ambient ozone treatment compared with control seedlings may be associated with the observed increase in soil nitrate concentration as a result of increased rates of leaf senescence and litterfall.     

Exencephaly in chicken‐pheasant hybrids

1. The incidence of exencephaly was investigated in chicken‐pheasant hybrids.

2. With the pheasant as sire, fertility was 7.lb6%, but with the fowl it was 19.lb5%; hatchability of fertile eggs, however, was similar, 42% and 41% respectively.

3. Only one exencephalic hybrid was obtained when the sire was the pheasant but 70 were noted when the fowl was sire. The incidence of this malformation in hatched chicks was 12 times more in crosses with the fowl as sire than in the reverse cross.

4. The frequency of exencephaly was greater with Rhode Island Red, Barred Leghorn or White Leghorn roosters than with Columbian Rock roosters.