scholarly journals A phenotypic marker for quantifying heat stress impact during microsporogenesis in rice (Oryza sativa L.)

2014 ◽  
Vol 41 (1) ◽  
pp. 48 ◽  
Author(s):  
Krishna S. V. Jagadish ◽  
Peter Craufurd ◽  
Wanju Shi ◽  
Rowena Oane

Gametogenesis in rice (Oryza sativa L.), and particularly male gametogenesis, is a critical developmental stage affected by different abiotic stresses. Research on this stage is limited, as flowering stage has been the major focus for research to date. Our main objective was to identify a phenotypic marker for male gametogenesis and the duration of exposure needed to quantify the impact of heat stress at this stage. Spikelet size coinciding with microsporogenesis was identified using parafilm sectioning, and the panicle (spikelet) growth rate was established. The environmental stability of the marker was ascertained with different nitrogen (75 and 125 kg ha–1) and night temperature (22°C and 28°C) combinations under field conditions. A distance of –8 to –9 cm between the collar of the last fully opened leaf and the flag leaf collar, which was yet to emerge was identified as the environmentally stable phenotypic marker. Heat stress (38°C) imposed using the identified marker induced 8–63% spikelet sterility across seven genetically diverse rice genotypes. Identifying the right stage based on the marker information and imposing 6 consecutive days of heat stress ensures that >95% of the spikelets in a panicle are stressed spanning across the entire microsporogenesis stage.

2019 ◽  
Vol 157 (04) ◽  
pp. 283-299 ◽  
Author(s):  
C. Malumpong ◽  
S. Cheabu ◽  
C. Mongkolsiriwatana ◽  
W. Detpittayanan ◽  
A. Vanavichit

AbstractThe reproductive stage of rice is the most sensitive to heat stress, which can lead to spikelet sterility. Thus, heat-tolerant and heat-susceptible genotypes were used to investigate their differences in terms of phenotypic responses and expression changes of Hsf genes at the pre-flowering stage under heat stress. Results clearly showed that panicles had the highest temperature compared with other plant parts under both natural and heated conditions. However, the temperatures of tolerant and susceptible genotypes were not significantly different. In terms of spikelet fertility, the tolerant lines M9962 and M7988 had high seed set because their anther dehiscence, pollen viability and pollen germination were only slightly affected. In contrast, the susceptible line Sinlek showed severe effects at all steps of fertilization, and the pollen viability of M7766 was slightly affected under heat stress but was more affected in terms of anther dehiscence and pollen germination. Both susceptible lines showed dramatically decreased seed set. In addition, the expression of six HsfA genes in the flag leaves and spikelets at the R2 stage of plants under heat stress showed different responses. Notably, expression of the HsfA2a gene was predominantly upregulated in the flag leaf and spikelets under heat stress in M9962. Therefore, it can be concluded that heat stress has severe effects on the stamen, and that different genotypes have different susceptibilities to heat stress.


2018 ◽  
Vol 38 (3) ◽  
pp. 210-215 ◽  
Author(s):  
Zhongjun Hu ◽  
Shulan Jin ◽  
Yizong Huang ◽  
Ying Hu ◽  
Wei Cheng ◽  
...  

2003 ◽  
Vol 53 (3) ◽  
pp. 255-262 ◽  
Author(s):  
Sohei Kobayashi ◽  
Yoshimichi Fukuta ◽  
Satoshi Morita ◽  
Tadashi Sato ◽  
Mitsuru Osaki ◽  
...  

Author(s):  
Ni Luh Suriani

The parameters developed in organic farming are the use of vegetable pesticides and compost and liquid organic fertilizer. Some research has been done but it needs deeper research to get the right product. The purpose of this study was to determine the inhibitory activity of Piper caninum extract against the fungus Pyricuaria oryzae causing blast disease in rice, and to find out how much the impact of compost on increased crop yield after being combined with the extract. This research is a field research located in the village of Senganan, Penebel Tabanan Bali. With the following treatment Fo = control (100% soil). F1 = (soil 90% + compost 10% + extract 0.5%). F2 = (soil 80% + compost 20% + extract 1%) F3 = (soil 70% + 30% + extract 1.5%). F4 = (soil 60% + compost 40% + 2% extract), do repeat 4 times. The results showed that P. caninum extract effectively inhibited blast disease and could reduce the intensity of blast disease. The combination with compost can significantly increase yields (67.62%), reduce empty grains, and increase rice size.


Author(s):  
Wei Zhang ◽  
Jinghua Long ◽  
Jianmin Geng ◽  
Jie Li ◽  
Zhongyi Wei

The impact of engineered nanoparticles (ENPs) on the migration and toxicity of coexisting pollutants is still unclear, especially in soil media. This study aims to evaluate the impact of titanium dioxide nanoparticles (TiO2 NPs) on the phytotoxicity of cadmium (Cd) to Oryza sativa L., and the migration of cadmium (Cd) in the soil-rice system. Three different Cd stress groups (C1 group: 1.0 mg kg−1, C2 group: 2.5 mg kg−1 and C3 group: 5.0 mg kg−1) were set in the pot experiment, and the target concentration of TiO2 NPs in each group were 0 mg kg−1 (T0), 50 mg kg−1 (T1), 100 mg kg−1 (T2) and 500 mg kg−1 (T3). Plant height and biomass decreased with the increasing of Cd content in paddy soil. TiO2 NPs could lower the phytotoxicity of Cd in terms of the changes in the morphological and biochemical characteristics, especially in the tillering and booting stage. In the tillering stage, TiO2 NPs addition caused a significant increase in plant height, biomass and the total chlorophyll content in the leaves of Oryza saliva L. In the booting stage, TiO2 NPs addition caused a 15% to 32% and 24% to 48% reduction of malondialdehyde (MDA) content for the C2 and C3 group, respectively, compared to that of the respective control treatment (T0). TiO2-NPs addition reduced the activity of peroxidase (POD) in the leaves in the booting and heading stage, and the activity of catalase (CAT) in the tillering stage. In the C1 and C2 group, the grain Cd content in the 100 and 500 mg kg−1 TiO2 NPs treatments reached 0.47–0.84 mg kg−1, obviously higher than that of the treatment without TiO2 NPs (0.27–0.32 mg kg−1), suggesting that TiO2-NPs could promote Cd migration in the soil-rice system.


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