Pine needle ultrastructure in an acid rain treatment : Air Pollution and Forest Decline. 14th International Meeting for Specialists in Air Pollution Effects on Forest Ecosystems

1989

S. 510-512

8 Abb., 3 Lit. Ang., En, Zfsg. En

Unselbständiges Werk

200034822

The ultrastructure of Scots pine (Pinus sylvestris) needles was examined in connection with an acid rain experiment undertaken at Kevo research station in northern Finland during the years 1986-1987. The experiment included pH 3, pH 4, clean water and dry control treatments. The samples were collected in May 1986, Juliy 1987 and October 1987. The mesophyll tissusse of the neeles treated with acid rain was seen to be partially disintegrated, especially near the hypodermis. Some alterations were also observed in the phloem. The size of the mesophyll chloroplasts varied considerably between the different needle years and on the different sampling dates, due to the starch grains which accumulate during summer, and which can as much as double the size of the chloroplasts. The dry control and the pH 3 treated needles almost always exhibited the smallest chloroplasts. The difference between summer and autumn was smallest in the pH 3 and pH 4 needles, which accumulate starch in summer. The increase of lipid material over the course of the time was evident in all samples, and especially obvious in the acid rain treated needles.