The Effect of Temperature on Pollen Germination, Pollen Tube Growth, and Stigmatic Receptivity in Peach

Abstract

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 degrees C in the laboratory and, on average, 5.7 degrees 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.

Sensitivity of flowering plant gametophytes to temperature fluctuations

“…Thus, for many of the cases in which an effect of temperature has been attributed to failure in pollen adhesion and germination at the stigma or in pollen tube growth within the style (previous section), a parallel failure in stigma and style receptivity cannot be ruled out. The length of stigmatic receptivity is shortened at high temperatures and enlarged at low temperatures in sweet cherry and peach regardless of the effect on the male side (Hedhly et al, 2003(Hedhly et al, , 2005b.…”

“…Temperature stress affects the very first step in pollen interaction with the pistil, adhesion to the stigma, as well as germination in a number of species (e.g. Hedhly et al, 2005b;Prasad et al, 2006). After penetrating the stigmatic surface, pollen tube growth proceeds along the transmitting tissue of the style and within the ovary towards the female gametophyte.…”

Floral adaptation and diversification under pollen limitation

“…Together, reduced pollen availability and inefficient pollen transfer must commonly contribute to PL of species with granular pollen because less than 1 per cent of the pollen removed from such species reaches conspecific stigmas (Harder & Johnson 2008). PL can also occur despite abundant pollen import if fewer male gametophytes access ovules than are necessary for complete fertilization, because of limited pollen-grain germination or pollen-tube attrition owing to self-incompatibility, gametophyte competition, cool temperatures or physical limits imposed by the cross-sectional area of stylar transmitting tissue (Hormaza & Herrero 1996;Hedhly et al 2005). Finally, zygote death due to the expression of lethal genes can reduce the number of embryos below a plant's capacity to mature seeds, given the available resources (Charlesworth 1989).…”

Genome-Wide Association Mapping of Fertility Reduction upon Heat Stress Reveals Developmental Stage-Specific QTLs in Arabidopsis thaliana

“…Besides maize, many other cereals, such as wheat (Triticum aestivum), barley (Hordeum vulgare), and rice (Oryza sativa), are affected by high temperatures during the reproductive phase (Barnabás et al, 2008). Negative effects of heat stress have also been reported for other important crops from various plant families, such as tomato (Solanum lycopersicum) (Sato et al, 2002(Sato et al, , 2006 and pepper (Capsicum annuum) (Marcelis et al, 2004) from the Solanaceae family, canola and mustard (Brassica juncea, Brassica rapa, and Brassica napus) (Angadi et al, 2000;Gan et al, 2004) from the Brassicaceae family, soybean (Glycine max) (Djanaguiraman et al, 2013) and chickpea (Cicer arietinum) (Clarke and Siddique, 2004) from the Fabiaceae family, and peach (Prunus persica) (Hedhly et al, 2005) and cherry (Prunus avium) (Hedhly et al, 2004) from the Rosaceae family. Thus, heat stress is an important factor that affects crop yields worldwide.…”