Effect of High Temperature Stress on Pollen Grains in Sunflower (Helianthus annuus L.) Inbred Lines

Abstract

High temperature at reproductive stage causes a decrease in seed set that ultimately results in yield loss in important crops. Limited research is available regarding the effect of high temperature on viability attributes of pollen grain in sunflower. This study was planned to reveal the effects of high temperature stress on pollen grains in sunflower. An experiment was laid out in a triplicated Completely Randomized Design with split-split plot arrangements at the Oilseeds Research Institute, Ayub Agricultural Research Institute Faisalabad during spring 2021. Two temperature treatments T1 = 45° C for 10, 20 and 30 minutes, and T2 = 50° C for 3, 5 and 10 minutes were used on 10 sunflower inbred lines. Normal (untreated) pollen grains were used as control (T0). Data were collected on pollen viability, pollen germination, and pollen tube length. Recorded data were subjected to analysis of variance, Tukey's HSD mean comparison test, and correlation. According to the results, ORI-1 showed the highest mean for pollen viability, whereas, RL-86 had highest mean for pollen germination and pollen tube length under normal conditions. RL-86 and ORI-73 revealed their ability to withstand both heat stresses as all pollen traits were least affected under high temperature stresses. It is advised to incorporate these inbred lines in future breeding programs aimed at the development of heat tolerant sunflower hybrids. Moreover, correlation studies displayed a positive, strong and highly significant relation of pollen germination with pollen tube length under normal and heat stress conditions revealing their importance in pollen study and reproduction. HIGHLIGHTS• Pollen grains of ten sunflower inbred lines were evaluated under normal and high temperature stress conditions.• Two temperature treatments and three treatment times were used as factors• Pollen viability, pollen germination percentage and pollen tube length decreased with increasing temperature and time period.• RL-86 and ORI-73 showed excellent ability to withstand high temperature stress.

Pollen Morphology of Some Species of the Genus Amelanchier Medik.

“…Empirical results showed that pollen grains were larger when under intense desiccation stress, but without change pollen grain shape. Plants are known to produce fewer pollen grains but larger sizes to avoid desiccation stress during the flowering period which studied some authors (Ejsmond et al, 2011;Mehmood et al, 2023). Yamburov et al (2014) studied effects of drought and flood stress on pollen quality and quantity in Clivia miniata including pollen size, viability, germination, and number of pollen grains per anther while evaluating how stress influences these features.…”

“…The data of the authors on the size of the pollen grains of same plant species are variable and may vary, often depending on environmental factors or pollen treatment in the analyses. Various external factors such as air temperature, precipitation, desiccation, flood stress, drought stress, plant nutrition and effect of herbicides can influence on the size of pollen grains (Dajoz et al, 1991;Delph et al, 1997;Ejsmond et al, 2011Ejsmond et al, , 2015Yamburov et la., 2014;Mehmood et al, 2023;Wrońska-Pilarek et al, 2023).…”

A review of the global climate change impacts, adaptation strategies, and mitigation options in the socio-economic and environmental sectors

“…Heat has a direct effect on flowers during the day, shortening their thesis period and hastening the onset of peak blooming (Liu et al, 2023). The seed set was significantly lower than could be explained by pollen sprouting at high temperatures of 40°C (Mehmood et al, 2023), suggesting that higher daytime temperatures have an antagonistic effect on pollen sprouting, leading to the hypothesis that seed set declines. Several studies found that rising temperatures are to blame for the decrease in wheat production (Karatayev et al, 2022;Kuriachen et al, 2022;Farhad et al, 2023).…”