TY - JOUR

T1 - Negative effects of high-temperature stress on gametophyte performance and their consequences for seed reproduction in wild plants

AU - Tushabe, Donam

AU - Altmann, Franziska

AU - Koehler, Erik

AU - Woods, Sebastian

AU - Rosbakh, Sergey

N1 - Publisher Copyright: © 2023 The Authors

PY - 2023

Y1 - 2023

N2 - (1) Plant regeneration by seeds is highly sensitive to temperature stress, particularly in the gametophyte stage. However, most of the existing research has focused on one single stage of gametophyte development and/or conducted using cultivated or a very few model species. Thus, it is unclear whether the results of such studies can be applied to natural populations. (2) To fill this gap, we investigated a) the effects of chronic heat stress (CHS; 17 days) at 35/30 °C (moderate stress) and 40/35 °C (severe stress) on gametophyte performance, and b) how these effects translated into seed quantity and quality. We measured six traits related to male (anther length, pollen production and size) and female (ovary length, ovule production, and size) gametophyte performance and leaf chlorophyll fluorescence (Fv/Fm) in four wild Silene species. The ripe seeds of the treated plants were used to measure seed mass and seed production; the seed germination was characterized in terms of germination percentage, speed, and synchrony. (3) Fv/Fm decreased significantly in both heat treatments, confirming a negative effect of CHS on overall plant performance. All male gametophyte traits decreased significantly in both CHS treatments compared to the control. The length and size of the ovary were significantly smaller in the 40/35 °C treatment than in the 35/30 °C treatment and the control, while ovule production decreased significantly in both CHS treatments compared to the control. The negative effects on gametophyte performance translated into significantly fewer seeds in the 35/30 °C and 40/35 °C treatments compared to the control. CHS treatments did not affect the seed mass. The final germination percentage differed weakly significantly between the severe treatment and the control but did not show any negative impacts by heat stress, whereas seed germination was significantly faster in the treated plants, both moderate and severe. Germination synchrony was not affected by heat treatments. (4) The high sensitivity of gametophytes in vascular plants to high-temperature stress implies that climate change-associated heat waves can significantly impact seed reproduction in wild plants. The altered seed quantity could have potential consequences for the long-term survival of the wild plant populations and the performance of the granivores.

AB - (1) Plant regeneration by seeds is highly sensitive to temperature stress, particularly in the gametophyte stage. However, most of the existing research has focused on one single stage of gametophyte development and/or conducted using cultivated or a very few model species. Thus, it is unclear whether the results of such studies can be applied to natural populations. (2) To fill this gap, we investigated a) the effects of chronic heat stress (CHS; 17 days) at 35/30 °C (moderate stress) and 40/35 °C (severe stress) on gametophyte performance, and b) how these effects translated into seed quantity and quality. We measured six traits related to male (anther length, pollen production and size) and female (ovary length, ovule production, and size) gametophyte performance and leaf chlorophyll fluorescence (Fv/Fm) in four wild Silene species. The ripe seeds of the treated plants were used to measure seed mass and seed production; the seed germination was characterized in terms of germination percentage, speed, and synchrony. (3) Fv/Fm decreased significantly in both heat treatments, confirming a negative effect of CHS on overall plant performance. All male gametophyte traits decreased significantly in both CHS treatments compared to the control. The length and size of the ovary were significantly smaller in the 40/35 °C treatment than in the 35/30 °C treatment and the control, while ovule production decreased significantly in both CHS treatments compared to the control. The negative effects on gametophyte performance translated into significantly fewer seeds in the 35/30 °C and 40/35 °C treatments compared to the control. CHS treatments did not affect the seed mass. The final germination percentage differed weakly significantly between the severe treatment and the control but did not show any negative impacts by heat stress, whereas seed germination was significantly faster in the treated plants, both moderate and severe. Germination synchrony was not affected by heat treatments. (4) The high sensitivity of gametophytes in vascular plants to high-temperature stress implies that climate change-associated heat waves can significantly impact seed reproduction in wild plants. The altered seed quantity could have potential consequences for the long-term survival of the wild plant populations and the performance of the granivores.

KW - Climate change

KW - Gametophyte

KW - Seed

KW - Temperature stress

KW - Wild plant

U2 - 10.1016/j.envexpbot.2023.105532

DO - 10.1016/j.envexpbot.2023.105532

M3 - Journal article

AN - SCOPUS:85174717867

VL - 216

JO - Environmental and Experimental Botany

JF - Environmental and Experimental Botany

SN - 0098-8472

M1 - 105532

ER -