Pollen tube kinetics is affected by temperatures during the flowering period

14 Aug 2023
1517

Environmental conditions during the cherry flowering season are a crucial factor influencing seed set and, consequently, fruit set. The potential impact of this factor on reproductive success is likely to increase considering the effects induced by global warming. 

In fact, for the sweet cherry, the Mediterranean area represents a borderline environment for its cultivation, and a further increase in temperatures could lead to a reduction in the area devoted to this crop. Pollen tube dynamics, which includes the time required for pollen germination and the pollen tube growth rate, is significantly affected by temperature.

Pollen germination is a highly variable parameter, whether it occurs between different species or between cultivars within the same species. In general, the optimal temperature range for pollen germination coincides with the average temperatures of the flowering period, and this relationship has been demonstrated in several fruit species. 

Pollen tube growth, on the other hand, is promoted by temperatures in both herbaceous and woody species.  The impact of temperature on pollen tube kinetics has been studied previously, but there is a lack of knowledge on how temperature affects pollen tube dynamics, particularly in terms of the population of male gametophytes that are able to reach the base of the style. 

Therefore, the hypothesis of temperature influence on the male gametophyte population can be considered plausible, but still not supported by scientific data. Therefore, the study conducted in experimental orchards in Zaragoza (Spain) by researchers from the Fruit Tree Crops Unit aimed to evaluate the impact of temperature on pollen kinetics in cherry trees

Specifically, two cultivars with different levels of adaptation to temperature were compared as pollen donors. The cultivar known as 'Sunburst' originated in Canada and can be counted among the northern European cultivars. The cultivar 'Cristobalina,' on the other hand, is native to southeastern Spain and has adapted to thrive in warmer climatic conditions. 

The effects of temperature were evaluated by experiments conducted in temperature-controlled chambers and in the field using plastic structures to cover the trees. The results show that optimal temperatures for pollen germination, pollen tube kinetics and pollen dynamics exhibit variation, indicating the presence of distinct regulatory mechanisms.

Increasing temperature resulted in a decrease in germination rate, but also in an acceleration of pollen tube growth rate within the style. In both genotypes, higher temperature caused a decrease in pollen germination while promoting the growth rate of pollen tubes.

The pollen tubes of Cristobalina showed a higher rate of reaching the base of the style of all flowers, compared to Sunburst, at the three temperatures examined (10°C, 20°C and 30°C). It is worth noting that the pollen tube growth rates of the Cristobalina species remained fairly constant at both 20°C and 30°C.

In contrast, the Sunburst species showed a significant increase in its growth rate precisely at 30°C. This variation suggests that adaptation to pollen donor temperature plays an important role in determining the observed effects. The observed decline in germination rates of both paternal genotypes with increasing temperature can potentially be attributed to the broader adaptation of sweet cherry to colder temperatures. 

The results of this study suggest that there is variation in genetic response to temperature during the reproductive phase. This variation may have significant implications for the ability of plant species to adapt to sudden changes in temperature.

Sourcee: Hedhly, A., Hormaza, J.I. and Herrero, M. (2004), Effect of temperature on pollen tube kinetics and dynamics in sweet cherry, Prunus avium (Rosaceae) . Am. J. Bot., 91: 558-564. https://doi.org/10.3732/ajb.91.4.558

Melissa Venturi
University of Bologna (IT)


Cherry Times - All rights reserved

What to read next

Picota del Jerte in trouble, appropriate insurance policies required against climate damage

Tech management

04 Dec 2024

The president of the Protected Designation of Origin Cherry of Jerte, José Antonio Tierno, lamented the loss of 40% of the season for cherries, which are harvested earlier, and 70% of picota, which matures later. This translates into economic losses exceeding 15 million euros.

Chilean producers call for activating domestic consumption by focusing on the old Corazón de Paloma cherry variety

Specialties

07 Jan 2025

Growers launched an unprecedented campaign to highlight the nutritional value and identity of the Corazón de Paloma cherry, a variety that, due to its organoleptic characteristics, is not chosen for export, but is preferred for domestic consumption by Ñuble families.

In evidenza

San José scale: a threat to nursery production even in protected environments

Nurseries

16 May 2025

A three-year study in Bulgaria shows that San Jose scale severely damages apples, cherries and plums grown both in protected and open fields. Infected propagation material significantly worsens plant quality and growth in nurseries.

Cherry production in crisis: challenges, mistakes and strategies for China export

Tech management

16 May 2025

Cherry growers face a crisis: overproduction, small sizes and poor quality threaten exports to China. Discipline, planning and targeted investments are now essential to produce premium fruit and recover competitiveness in global markets.

Tag Popolari