Comparison of fructan dynamics in two wheat cultivars with different capacities of accumulation and remobilization under drought stress

Abstract

Remobilization of stored carbohydrates in the stem of wheat plants is an important contributor to grain filling under drought stress (DS) conditions. A massive screening on Iranian wheat cultivars was performed based on stem dry weight changes under well-watered and DS conditions. Two cultivars, Shole and Crossed Falat Hamun (CFH), with different fructan accumulation and remobilization behavior were selected for further studies. Water-soluble carbohydrates (WSCs) and fructan metabolizing enzymes were studied both in the stem penultimate and in sucrose (Suc) treated, excised leaves. Under drought, CFH produced higher grain yields than Shole (412 vs 220 g m(-2)). Also, grain yield loss under drought was more limited in CFH than in Shole (17 vs 54%). Under drought, CFH accumulated more graminan-type fructo-oligosaccharides than Shole. After anthesis, fructan 6-exohydrolase (6-FEH; EC 3.2.1.154) activities increased more prominently than fructan 1-exohydrolase (EC 3.2.1.153) activities during carbon remobilization. Interestingly, CFH showed higher 6-FEH activities in the penultimate than Shole. The field experiment results suggest that the combined higher remobilization efficiency and high 6-FEH activities in stems of wheat could contribute to grain yield under terminal drought. Similar to the penultimate, fructan metabolism differed strongly in Suc-treated detached leaves of selected cultivars. This suggests that variation in the stem fructan among wheat cultivars grown in the field could be traced by leaf blade induction experiments.

Stem Reserve Mobilization in Relation to Yield under Different Drought and High Temperature Stress Conditions in Wheat (Triticum aestivum L.) Genotypes

“…Genotype DHTW-60, WH-1105 & HD-2967 showed higher SRM at different time of drought application and different sowing condition in peduncle and penultimate internode (Table 1an 2). The results of present investigation are supported by earlier finding of Gupta et al, 2011;Joudi et al, 2012;Zhang et al, 2014). Sharifi et al, (2017) found similar result in wheat genotypes under water-deficit treatments with 50 to 80 % higher mobilization than the in well-watered treatments, which indicates that water deficits promoted remobilization.…”

Involvement of abscisic acid in fructan hydrolysis and starch biosynthesis in wheat under soil drying

“…The grain filling of cereals depends on carbon from two sources: current assimilation and remobilization of reserves stored in the stem either pre-or post-anthesis Joudi et al 2012). Most estimates of the contribution of stem reserves to grain filling are 20-50 % of the final grain weight in non-stress conditions (Rawson and Evans 1971;Schnyder 1993;Wardlaw and Willenbrink 2000).…”

Changes in stem and spike related traits resulting from breeding in Iranian wheat cultivars: associations with grain yield

“…As the total amount of stem contributions to grain yield was the same in the taller and shorter cultivars (Joudi unpublished), the decrease in carbohydrate accumulation and remobilization imposed by length reduction is expected to be compensated by higher SSW in the shorter cultivars. Joudi et al (2012) reported that both carbohydrate amounts and remobilization efficiency per unit stem length were higher in modern cultivars, as compared to the old ones. Therefore, the reduction of stem length (data not shown) and an increase of SSW in modern cultivars suggest that plant breeders should pay more attention to SSW than to stem weight or length.…”