Biotic and Abiotic stress
Navid Taherifar; Hengameh Taheri
Abstract
Heat stress has detrimental effects on the growth and performance of plants through biochemical, physiological, morphological, and molecular changes. Plants have developed complex mechanisms to balance growth and tolerance to stress, allowing them to effectively defend against more severe stresses by ...
Read More
Heat stress has detrimental effects on the growth and performance of plants through biochemical, physiological, morphological, and molecular changes. Plants have developed complex mechanisms to balance growth and tolerance to stress, allowing them to effectively defend against more severe stresses by remembering mild stress and forming heat stress memory, known as thermopriming. To investigate the role of thermopriming in inducing the transcription response of HSFA2, HSFA1b and MIPS2 genes, the changes in the transcriptional level of the genes were studied at different times after priming and return stress in canola seedlings using the qRT-PCR technique. The results showed that the expression of these genes was not stable during the recovery period after the initial mild stress (memory phase), while their transcription level immediately after facing the second severe stress was induced at a much higher level in primed plants (P+T treatment) compared to non-primed plants (T treatment) which continued until 48 hours after return stress. Also, morphological analysis of seedlings at 7 and 14 days after release from the second stress showed that thermopriming increase the growth indices and heat tolerance in these plants through strengthening the expression of stress memory genes. Since the HSFA1b, HSFA2 and MIPS2 genes have maintained their expression level until days after the return stress, these genes can be the key components of the transcriptional memory of heat stress and be used in breeding programs and the development of heat tolerant varieties.
Tissue culture and Micropropagation
Pegah Moradi Dezfouli; Mohammad Sedghi; Mehran Enayati Shariatpanahi; Bahram Alizade
Volume 7, Issue 18 , November 2017, , Pages 1-14
Abstract
In this research, Hayola F1 hybrids were used to produce rapeseed doubled haploid lines using microspore embryogenesis. To study general combining ability (GCA) of, the induced doubled haploid (DH) rapeseed lines, a top cross analysis was conducted using 28 doubled haploid lines and top cross parent ...
Read More
In this research, Hayola F1 hybrids were used to produce rapeseed doubled haploid lines using microspore embryogenesis. To study general combining ability (GCA) of, the induced doubled haploid (DH) rapeseed lines, a top cross analysis was conducted using 28 doubled haploid lines and top cross parent of Hayola 420. Produced hybrids of doubled haploid lines × Hayola 420 were sown in research farm in 2015 growing season. Plant height, number of pods per branch and sub branches, number of seeds per pod, pod length, number of sub branches, length of main branch, 1000-seeds weight, single plant yield, number of days to flowering, number of days to seeding, number of days to physiological maturity, and oil yield were recorded in all top cross progeny to investigate GCA of DH lines. Results of analysis of variance showed a significant difference among all top cross hybrids for all investigated traits at 1% probability level. Based on means comparison analysis using multiple range Duncan test at 1% probability level, top cross hybrids of DH1, DH8, DH10, DH11, DH13, and DH21 were more differ than other top cross hybrids for all investigated characteristics. The highest mean of seed yield and oil yield was related to the top cross progeny of DH21 × Hayola 420. Results of top cross analysis showed that the highest positive and significant GCAs for single plant seed yield, number of pods per plant, and 1000-seeds weight were corresponded to DH1, DH10, and DH21, therefore these three DH lines can be used as elite parental lines in future breeding programs of rapeseed.
Tissue culture and Micropropagation
Peyman Sharifi; Ahmad Moieni
Volume 6, Issue 13 , May 2016, , Pages 13-26
Abstract
The effect of some factors on embryogenesis from isolated microspore and plantlet regeneration from microspore-derived embryos was studied separately in Brassica napus. Experiments carried out in factorial based on completely randomized design. The first factor in all of the experiments was cultivars ...
Read More
The effect of some factors on embryogenesis from isolated microspore and plantlet regeneration from microspore-derived embryos was studied separately in Brassica napus. Experiments carried out in factorial based on completely randomized design. The first factor in all of the experiments was cultivars contained Global, Option and PF7045/91. The microspores were isolated from 3-4 mm buds and cultured on NLN-13 medium. Cultures incubated at 30˚C and darkness for 14 days, and then transferred to shaker in the growth chamber at 25˚C. In regeneration experiment, embryos with 20-25 days old were transferred to B5 medium and nearly 20-25 days after transferring embryos, normal regenerated plantlets, abnormal regenerated plantlets, rooted embryos and non differentiated embryos were counted. In the first embryogenesis experiments, the effects of medium volume, cultivar and interaction effects of two factors were significant. In Global cultivar, the highest values of embryos (695.5 per Petri) were observed in 12.5 ml medium volume. In the second embryogenesis experiment, the interaction between activated charcoal and cultivar on embryogenesis was significant. In the third embryogenesis experiment, the form of carbohydrate had a significant effect on embryo yield. In the first experiment of plantlet regeneration, GA3 had significant effect on normal regenerated plantlets, abnormal regenerated plantlets, rooted embryos and non differentiated embryos and the interaction between GA3 and cultivar was significant for normal regenerated plantlets. In the second experiment of plantlet regeneration, the interaction between gelling agent and cultivar was significant on normal regenerated plantlets.
