Plant Biol. 7: 476-483 (2005)
The Effect of Temperature on Pollen Germination, Pollen Tube Growth, and Stigmatic Receptivity in Peach
A. Hedhly1,2, J. I. Hormaza3, and M. Herrero1,2

1 Estación Experimental de Aula Dei, CSIC, Apartado 202, 50080 Zaragoza, Spain
2 Unidad de Fruticultura, CITA DGA, Apartado 727, 50080 Zaragoza, Spain
3 Estación Experimental La Mayora, CSIC, 29750 Algarrobo Costa, Malaga, Spain

Temperature is a major climatic factor that limits geographical distribution of plant species, and the reproductive phase has proven to be one of the most temperature-vulnerable stages. Here, we have used peach to evaluate the effect of temperature on some processes of the progamic phase, from pollination to the arrival of pollen tubes in the ovary. Within the range of temperatures studied, 20°C in the laboratory and, on average, 5.7°C in the field, the results show an accelerating effect of increasing temperature on pollen germination and pollen tube growth kinetics, as well as an increase in the number of pollen tubes that reach the style base. For the last two parameters, although the range of temperature registered in the field was much lower, the results obtained in the laboratory paralleled those obtained in the field. Increasing temperatures drastically reduced stigmatic receptivity. Reduction was sequential, with stigmas first losing the capacity to sustain pollen tube penetration to the transmitting tissue, then their capacity to offer support for pollen germination and, finally, their capacity to support pollen grain adhesion. Within a species-specific range of temperature, this apparent opposite effect of temperature on the male and female side could provide plants with the plasticity to withstand changing environmental effects, ensuring a good level of fertilization.

This brief note can be compared with a different report by Zamir et al. (1981). Together they suggest that by regulating the temperature we may also select for favored responses to temperature. I.e., if we pollinate a tomato by a hybrid of Lycopersicon esculentum and L. hirsutum, low temperatures should favor the gametes carrying genes related to cold tolerance.