Heat stress affects vegetative and reproductive performance and trait correlations in tomato (Solanum lycopersicum)

Jiemeng Xu,Heidrun Huber,Mieke Wolters-Arts,Celestina Mariani,Ivo Rieu

doi:10.1007/s10681-017-1949-6

Abstract

High ambient temperature has adverse effects on plant vegetative and reproductive development and reduces crop yield. To better understand the importance of male and female fertility for tomato fruit set ability under high temperature conditions and to test whether heat tolerance levels among and between reproductive and vegetative traits of genotypes correlate with each other, 13 tomato cultivars were subjected to long-term moderate heat (LTMH) or short-term heat shock (STHS), depending on the trait that was evaluated. LTMH caused significant decrease in performance of nearly all reproductive traits, i.e. pollen viability, pollen number, female fertility, seeded-fruit set and flower number per inflorescence, but not in inflorescence number. Considerable variation was found among cultivars, both under control and LTMH conditions. The cultivars Nagcarlang, Saladette and Malintka 101 produced a higher percentage of viable pollen under LTMH. For fruit set under LTMH condition, only cultivars that had been previously reported as being heat-tolerant produced fruits with seeds. STHS negatively affected vegetative traits concerning seedling survival and membrane stability. Correlation analysis revealed relationships between various traits within the control and heat treatments, but not between the two. Under heat stress fruit set was positively correlated with pollen viability, as well as with flower number per inflorescence. However, no significant correlations were found between vegetative and reproductive traits. Our data highlight the prominent role of pollen viability for tomato fertility under LTMH growth conditions. The observed variation in thermotolerance among different cultivars offers the possibility to decipher underlying physiological and genetic mechanisms.

Highlights

When plants experience ambient temperatures higher than optimal in the form of either long-term moderate heat (LTMH) or short-term heat shock (STHS), it may lead to disruption of cellular and organismal homeostasis, known as heat stress
When experiencing pre-anthesis LTMH, flowers had reduced pollen production, pollen viability, pollen shedding, ovule viability and stigma receptivity, and increased physical distance between stigma and anther cone (Kinet and Peet 1997). While all these abnormalities can occur, it is not fully clear which aspects are the most limiting for Euphytica (2017) 213:156 tomato fruit set under heat stress and whether tolerance levels for the various processes are related to each other
To assess male reproductive performance, pollen viability (PV) and pollen number at flower anthesis were analysed under control and LTMH conditions

Summary

Introduction

When plants experience ambient temperatures higher than optimal in the form of either long-term moderate heat (LTMH) or short-term heat shock (STHS), it may lead to disruption of cellular and organismal homeostasis, known as heat stress Basic physiological processes, such as photosynthesis, assimilate partitioning, growth and development are adversely affected (Bokszczanin et al 2013). When experiencing pre-anthesis LTMH, flowers had reduced pollen production, pollen viability, pollen shedding, ovule viability and stigma receptivity, and increased physical distance between stigma and anther cone (Kinet and Peet 1997) While all these abnormalities can occur, it is not fully clear which aspects are the most limiting for Euphytica (2017) 213:156 tomato fruit set under heat stress and whether tolerance levels for the various processes are related to each other. Screening of sets of tomato cultivars and wild relatives for reproduction under heat stress (LTMH or STHS) has revealed considerable, heritable natural variation in heat tolerance and several studies suggested that viability of male and female gametes, as well as the level of style protrusion are major determinants for reproductive success under these conditions, dependent on the cultivars studied (Rick and Dempsey 1969; Rudich et al 1977; Levy et al 1978; Dane et al 1991; Saeed et al 2007; Bhattarai et al 2016)

Methods

Results

Discussion

Conclusion