Table 2.

Summary table of the impact of high temperature on the pollen metabolome in different species. HS, heat stress.

Common name	Latin name	Metabolites	Temperatures	Heat-stress length	Plant material used	Impacts	References
tomato	Solanum lycopersicum	Carbohydrates	32 °C/26 °C	Four months	Flowers totally developed under HS	Decrease in pollen mature	[33]
			32 °C/26 °C	Three months	Flowers totally developed under HS	Sugar abundance decreased in thermo-sensitive genotype compare to thermo-tolerant ones	[12]
			36 °C/28 °C	24 h	Plants at four days after anthesis	Decrease of acid invertase activity in flowers of sensitive genotype compare to tolerant genotype	[14]
		Proline	32 °C/26 °C	Long	Flowers totally developed under HS	Proline transporter expression decreased in anthers	[100]
		Polyamines	33 °C, 35 °C, 38 °C	20 h	Pollen germination medium	Adding polyamines improved in-vitro pollen germination	[139]
			38 °C	4 h	Pollen germination medium	Decrease in pollen mature	[138]
		Brassinosteroids	35 °C	4 h	Pollen germination medium	Adding brassinosteroids improved in-vitro pollen germination	[142]
		Ethylene	32 °C/26 °C	Three months	Flowers totally developed under HS	Ethylene transporter mutation decreased pollen viability	[46]
barley	Hordeum vulgare	Auxin	30 °C/25 °C	Five days	Plants at five leaf stage	Decrease in anther and exogenous auxin restored male sterility	[147]
rice	Oryza sativa	Proline	39 °C	4 h per day during five days	Plants at flowering stage	Decrease in anther	[133]
		Auxin	39 °C	5 h per day during five days	Plants at flowering stage	Decrease in anther	[133]
		Gibberelin	39 °C	4 h per day during five days	Plants at flowering stage	Decrease in anther	[133]
		Abscisic acid	39 °C	4 h per day during five days	Plants at flowering stage	Increase in anther	[133]
arabidopsis	Arabidopsis thaliana	Auxin	30 °C/25 °C	Five days	Plants at five leaf stage	Decrease in anther and exogenous auxin restored male sterility	[147]
bell pepper	Capsicum annuum	Carbohydrates	32 °C/26 °C	For eight days before anthesis	Plants at flowering stage	Increase of sucrose due to a decrease of acid invertase activity	[111]
sorghum	Sorghum bicolor	Carbohydrates	36 °C/26 °C	Long-season	Flowers totally developed under HS	Decrease of sucrose and starch in pollen mature	[130]
		Lipids	32 °C/28 °C	Ten days	Plants at 40 days after sowing	Decrease of saturated fatty acids which weaken the membrane to ROS attack	[134]
chickpea	Cicer arietinum	Carbohydrates	Above 32 °C/20 °C	Long	Flowers totally developed under HS	Decrease of sugars in sensitive genotypes compare to tolerant genotype in anthers. Tolerant genotype increased hexose abundance in anthers compare to sensitive genotype.	[113]
lily	Lilium auratum	Proline	40 °C	10 min	Pollen germination medium	Adding proline improved in-vitro pollen germination	[132]
cowpea	Vigna unguiculata	Proline	45 °C/25 °C	Long	Flowers totally developed under HS	Proline accumulated in anther wheareas in pollen it decreased. Tolerant genotype had a higher abundance of proline in pollen	[50]
soybean	Glycine max	Lipids	From 30 °C/23 °C to 39 °C/20 °C	Ten days	Flowering stage	Decrease of saturated phospholipids	[11]
japanese abricot	Prunus mume	Polyamines	35 °C	24 h	Pollen germination medium	Addind polyamines did not improve pollen germination	[140]