An improvedin vitrogermination medium for recalcitrant bread wheat (Triticum aestivumL.) pollen

Abstract

There is no robust and quick technique available for testing germination of wheat pollen. In this study, Brewbaker and Kwack (BK) pollen germination medium (PGM) was adjusted with α α α α α-amino caproic acid (EACA), peptone water and maltose to develop an improved medium for wheat. Germination of pollen in this PGM ranged from 92% to 98.2% depending upon genotype pollen germination media (PGM). This is the first report of PGM which has >95% wheat pollen germination in vitro.

Quantifying the Impact of Heat Stress on Pollen Germination, Seed Set, and Grain Filling in Spring Wheat

“…For measuring pollen germination, florets opening on the second day of flowering were collected from the tagged plants from each treatment (24/16 and 34/16°C) between 0530 and 0630 h. To determine pollen germination in different genotypes under control and heat stress, liquid pollen germination medium (without agar and peptone water) was prepared by dissolving H 3 BO 3 (50 mg), Ca(NO 3 ) 2´4 H 2 O (30 mg), MgSO 4´7 H 2 O (200 mg), KNO 3 (100 mg), amino caproic acid (EACA; 50 mg), maltose (18%), and polyethylene glycol (PEG, 13%) at 6 pH as reported by Jayaprakash et al (2015). After 10 d of heat stress (34/16°C, day/night) exposure, plants were transferred back to control temperature conditions (24/16°C, day/night) and maintained until physiological maturity.…”

“…The impact of heat when first signs of external appearance of anther was observed on a given flowering day) and last floret opening on a flowering day were recorded in the morning (0530 to 0630 h) and in the evening (1600 to 1800 h), respectively, over 3 d under control conditions. For measuring pollen germination, florets opening on the second day of flowering were collected from the tagged plants from each treatment (24/16 and 34/16°C) between 0530 and 0630 h. To determine pollen germination in different genotypes under control and heat stress, liquid pollen germination medium (without agar and peptone water) was prepared by dissolving H 3 BO 3 (50 mg), Ca(NO 3 ) 2´4 H 2 O (30 mg), MgSO 4´7 H 2 O (200 mg), KNO 3 (100 mg), amino caproic acid (EACA; 50 mg), maltose (18%), and polyethylene glycol (PEG, 13%) at 6 pH as reported by Jayaprakash et al (2015). Pollen grains from individual florets at or just after opening were dusted on to the germination medium with the help of forceps, and the chamber slides with pollen grains were incubated at 24°C for 4 h (Ecotherm Incubator, Torrey Pines Scientific).…”

Assessment of Pollen Viability for Wheat

“…To assess pollen tube growth, liquid media based on Cheng and McComb (1992); Jayaprakash et al (2015), and Jian et al (2014) were modified in contents of CaCl 2 •2H 2 O/ Ca(NO 3 ) 2 •2H 2 O, H 3 BO 3 and the effect of different sugars and pH values was evaluated. Media were prepared using between 300 and 900 mM of sucrose, maltose, and raffinose and pH was adjusted to 5.8 and 7.3 (Supplementary Table S2).…”

“…Media were prepared using between 300 and 900 mM of sucrose, maltose, and raffinose and pH was adjusted to 5.8 and 7.3 (Supplementary Table S2). The media according to Jayaprakash et al (2015) and Jian et al (2014) contained 0.81 mM MgSO 4 •7H 2 O and 0.99 mM KNO 3 in addition.…”

“…For wheat pollen, Cheng and McComb (1992) achieved maximum pollen tube length on medium containing raffinose. Due to high expenditures for raffinose, Jian et al (2014) and Jayaprakash et al (2015) replaced raffinose either by sucrose or maltose, respectively and achieved pollen germination up to 95% (Jayaprakash et al, 2015). However, except of these studies, wheat pollen germination has not been investigated in greater detail up to now.…”