Interactive effects of carbon dioxide, temperature, and ultraviolet-B radiation on soybean (Glycine max L.) flower and pollen morphology, pollen production, germination, and tube lengths

Abstract

Plant reproduction is highly vulnerable to global climate change components such as carbon dioxide concentration ([CO(2)]), temperature (T), and ultraviolet-B (UV-B) radiation. The objectives of this study were to determine the effects of season-long exposure to treatments of [CO(2)] at 360 (control) and 720 micromol mol(-1) (+CO(2)), temperature at 30/22 degrees C (control) and 38/30 degrees C (+T) and UV-B radiation 0 (control) and 10 kJ m(-2) d(-1) (+UV-B) on flower and pollen morphology, pollen production, germination, and tube lengths of six soybean genotypes (D 88-5320, D 90-9216, Stalwart III, PI 471938, DG 5630RR, and DP 4933RR) in sunlit, controlled environment chambers. The control treatment had 360 micromol mol(-1) [CO(2)] at 30/22 degrees C and 0 kJ UV-B. Plants grown either at +UV-B or +T, alone or in combination, produced smaller flowers with shorter standard petal and staminal column lengths. Flowers so produced had less pollen with poor pollen germination and shorter tube lengths. Pollen produced by the flowers of these plants appeared shrivelled without apertures and with disturbed exine ornamentation even at +CO(2) conditions. The damaging effects of +T and +UV-B were not ameliorated by +CO(2) conditions. Based on the total stress response index (TSRI), pooled individual component responses over all the treatments, the genotypes were classified as tolerant (DG 5630RR, D 88-5320: TSRI >-790), intermediate (D 90-9216, PI 471938: TSRI <-790 to >-1026), and sensitive (Stalwart III, DP 4933RR: TSRI <-1026). The differences in sensitivity identified among genotypes imply the options for selecting genotypes with tolerance to environmental stresses projected to occur in the future climates.

Disrupted continental environments around the Devonian-Carboniferous Boundary: introduction of the tener event

“…Higher percentages of abnormal forms (>3% after Foster & Afonin, 2005) cannot be explained by natural variation and it requires external mutagen factors. Such factor are basically environmental (hydric stress, high temperature, increased CO2 atmospheric content; Mulcahy, 1981;Koti et al, 2005), pollution (heavy metal, acid rain; Visscher et al, 2004;Foster & Afonin, 2005) and UV-B radiation (stratospheric ozone destruction). Filipiak & Racki (2010) invoked the volcanic activity as a potential source of mutation leading to an abnormal palynological association in the uppermost Famennian from the Holy Cross Mountains.…”

Sensitivity of flowering plant gametophytes to temperature fluctuations

“…Intra-specific variability has indeed been extensively reported in cultivated plant species for many reproductive characteristics. Genotype-specific responses have been reported for stress applied during microsporogenesis affecting carbohydrate metabolism, degeneration of the tapetal tissues, pollen wall architecture, pollen morphology, pollen viability, anther dehiscence and pollen production (Aloni et al, 2001;Koti et al, 2005;Oliver et al, 2005;Porch and Jahn, 2001;Prasad et al, 2006;Pressman et al, 2002;Srinivasan et al, 1999;Suzuki et al, 2001). At the post-anthesis level, pollen germination (Hedhly et al, 2005a;Kakani et al, 2002Kakani et al, , 2005, pollen tube growth rate (Clarke and Siddique, 2004;Hedhly et al, 2004;Srinivasan et al, 1999), and pollen dynamics (Hedhly et al, 2005a) also show genotype-specific responses.…”

Effect of high temperature on the reproductive development of chickpea genotypes under controlled environments

“…Halterlein et al (1980) reported that pollen viability in common bean decreased when temperatures were held at 35/20˚C or 35˚C for a 24 h period just before anthesis. Shrunken pollen was observed at 38/30˚C in heat tolerant soybean (Glycine max L.) (Koti et al 2005).…”