The influence of ozone on Pinusstrobus L. pollen germination

Abstract

Along the Blue Ridge Parkway in Virginia, branchlets and pollen were collected from native eastern white pine (Pinusstrobus L.) trees that were sensitive, intermediate, and tolerant to oxidant air pollution based on foliar symptom expression. Fumigation of branchlets with 0.10 ppm ozone (O3) for 4 or 8 h/day until anthesis did not affect pollen production or germinability. However, the percent germination was significantly (P ≤ 0.01) reduced in pollen exposed under wet conditions to 0.15 O3 for 4 h. The importance of this finding in the reproduction of pines is discussed.

A Review of the Effects of Major Atmospheric Pollutants on Pollen Grains, Pollen Content, and Allergenicity

“…Some other studies focused on zones known for their different levels of regularly measured pollution in order to compare the pollen material at the different polluted sites [ 41 , 42 ]. Transects were also used, for instance, along a specific road [ 43 ] or according to the altitude [ 44 , 45 ]. In different continents, some authors investigated forest zones [ 46 – 51 ], sometimes under specific sophisticated ecological protocols [ 52 ] including the simulation of acid rain on selected trees from experimental orchards before the collect phase of pollen material [ 53 ].…”

Tansley Review No. 115

“…Hormaza et al (1996) also reported a correlation between the ozone sensitivity of vegetative organs and pollen for various fruit and nut tree species (Table 1), and suggested that ozone might affect metabolic steps common to both sporophytic and gametophytic growth stages. However, Benoit et al (1983) found no correlation between foliar symptoms and the sensitivity of pollen in P. strobus. Reiling & Davison (1992a) suggested that effects on growth are a more useful indicator of ozone sensitivity as they can occur in the absence of visible symptoms.…”

Impact of O3 and SO2 on reproductive development in oilseed rape (Brassica napus L.). I. Pollen germination and pollen tube growth

“…For instance, exposure to O3 in culture produced no significant effect in any of the replicate experiments, whereas significant effects were observed in some of the replicate experiments in which pollen was exposed in a dry state. In contrast, moist pollen of Pinus strobus has been reported to be more sensitive to O3 than dry pollen (Benoit, Skelly & Moore, 1983), and Wolters & Martens (1987) considered that this was because the presence of moisture brings pollen into contact with the dissolved products of pollutants. However, O3 is very much less soluble in water than SO.^ (Tingey & Taylor, 1982) and the presence of moisture might act as a barrier to ozone, reducing its access to pollen or preventing the formation of toxic secondary products and thereby minimizing or eliminating their adverse effects.…”