scholarly journals Detrimental effects of heat stress on grain weight and quality in rice (Oryza sativa L.) are aggravated by decreased relative humidity

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11218
Author(s):  
Haoliang Yan ◽  
Chunhu Wang ◽  
Ke Liu ◽  
Xiaohai Tian

There is concern over the impact of global warming on rice production due increased heat stress, coupled with decreased relative humidity (RH). It is unknown how rice yield and quality are affected by heat stress and decreased RH during the grain filling stage. We conducted experiments in controlled growth chambers on six rice cultivars, varying in heat tolerance using 12 combinative treatments of three factors: two RH levels (75% and 85%), three temperature levels (the daily maximum temperature at 33 °C, 35 °C, and 37 °C), and two durations (8 d and 15 d after anthesis). Results showed that RH75% with temperature treatments significantly reduced grain weight, which was higher than RH85%. The same trend was also observed for both head rice rate and chalkiness. R168 was the most heat-tolerant cultivar, but it still had some differences in grain weight, head rice rate, and chalkiness between the two RH regimes. The lower RH was most detrimental at 35 °C, and to a lesser extent at 33 °C, but had a negligible effect at 37 °C. Our results provide a better understanding of temperature and RH’s interaction effects on rice quality during the grain filling stage, suggesting that RH should be considered in heat tolerance screening and identification to facilitate rice breeding and genetic improvement.

2021 ◽  
Vol 67 (No. 2) ◽  
pp. 71-76
Author(s):  
Milan Mirosavljević ◽  
Sanja Mikić ◽  
Ankica Kondić Špika ◽  
Vesna Župunski ◽  
Rong Zhou ◽  
...  

High temperature decreases winter wheat grain yield by reducing the grain number and grain weight. The effect of heat stress on spike grain distribution and weight of individual grains within spike and spikelets was less studied. Our aim is to identify influence of high temperatures during different phenological stages on spike grain distribution and weight and to explore genotypic variation of the studied wheat cultivars. Within this study, a controlled experiment was conducted with 12 different winter wheat cultivars under heat stress at anthesis and mid-grain filling stage. The results showed that spike grain weight, thousand-grain weight and grain number per spike decreased moderately in treatments with individual heat stress at anthesis and mid-grain filling period, respectively, which decreased severely in the multiple heat stressed plants at both stages compared with the control treatment. Heat stress decreased number of spikelets with grains. Grain weight at the G1, G2 and G3 positions had a positive relationship with spike grain weight. Among the studied Serbian wheat cultivars Subotičanka and Renesansa were identified as the most heat tolerant and sensitive, respectively. Heat tolerance of the studied cultivars should be based on the cultivar capacity to retain higher grain weight, and to maintain production of distal spikelet grains.


Agronomy ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1871
Author(s):  
Diego Rubiales ◽  
Ana Moral ◽  
Fernando Flores

There is potential for expanding lentil cultivation to dry and warm Mediterranean rain-fed environments at low altitudes, where early sowings are recommended to profit from winter rains and escape drought and excessive heat at the grain filling stage. In cooler areas, frost might be a problem in the early sowings, however, in warmer areas such as our low altitude warm southern Spanish environments the most detrimental factor on lentil seed yield appeared to be high temperatures at grain-filling stage, particularly heat waves of more than 5 days with Tmax > 30 °C. This was followed by broomrape infection, the combination of both being dramatic. We detected variation for stress tolerance, with S17 and R7 accessions outstanding for all stress indexes used, followed by S23, Nsir, S6, and S12. Broomrape infection ranked second risk in the area. No complete resistance to broomrape was identified, but there was a significant variation in the level of infection, with accessions S14 and R17 being the more resistant across environments. This offers prospects for combining heat tolerance and broomrape resistance by breeding.


2019 ◽  
Author(s):  
Shengjing Ni ◽  
Huifang Zhao ◽  
Guoping Zhang

Abstract Background: Malt barley shows a dramatic deterioration of malt quality when exposed to heat or high temperature stress during grain-filling stage (post heading), and global change results in the more frequent occurrence of high temperature, posing a severe threat to high-quality malt barley production. In a previous study, we found heat stress during grain-filling stage caused the significant reduction of kernel weight, and the significant increase of protein and β-glucan content, and β-amylase and limit dextrinase (LD) activities, and the effect varied with barley genotypes and the time of heat stress exposure.Results: In this study, we determined the relative expressions of HvCslF6 and HvCslF9 for β-glucan, HvBmy1 for β-amylase and LD gene for limit dextrinase of two barley cultivars(ZU9 and Hua30)under the two heat stress (HS) treatments (32/26℃, day/night), initiated from the 7th day (early grain-filling stage) and the14th day (middle grain-filling stage) after heading. In comparison with normal temperature (24/18℃, day/night), HS treatments significantly up-regulated the relative expression of all four genes, and Hua30 being larger than ZU9. The change pattern of each examined gene for the two barley genotypes under heat stress treatments is completely consistent with that of corresponding malt quality trait as affected by heat stress.Conclusion: The results indicate that the enhancement of β-glucan content, and β-amylase and limit dextrinase activities under high temperature during grain filling stage is at least in part attributed to increased expression of the relevant genes.


2018 ◽  
Vol 19 (10) ◽  
pp. 2945 ◽  
Author(s):  
Weiwei Lin ◽  
Xiaodong Guo ◽  
Xinfeng Pan ◽  
Zhaowei Li

To evaluate the effect of changes in chlorophyll (Chl) composition and fluorescence on final yield formation, early senescence leaf (esl) mutant rice and its wild-type cultivar were employed to investigate the genotype-dependent differences in Chl composition, Chl fluorescence, and yield characteristics during the grain-filling stage. However, the temporal expression patterns of key genes involved in the photosystem II (PSII) reaction center in the leaves of two rice genotypes were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). Results showed that the seed-setting rate, 1000-grain weight, and yield per plant remarkably decreased, and the increase in the 1000-grain weight during the grain-filling stage was retarded in esl mutant rice. Chl composition, maximal fluorescence yield (Fm), variable fluorescence (Fv), a maximal quantum yield of PSII photochemistry (Fv/Fm), and net photosynthetic rate (Pn) in esl mutant rice considerably decreased, thereby indicating the weakened abilities of light energy harvesting and transferring in senescent leaves. The esl mutant rice showed an increase in the minimal fluorescence yield (F0) and 1 − Fv/Fm and decreases in the expression levels of light-harvesting Chl a/b binding protein (Cab) and photosystem II binding protein A (PsbA), PsbB, PsbC, and PsbD encoding for the reaction center of the PSII complex during the grain-filling stage. These results indicated the PSII reaction centers were severely damaged in the mesophyll cells of senescent leaves, which resulted in the weakened harvesting quantum photon and transferring light energy to PSI and PSII for carbon dioxide assimilation, leading to enhanced heat dissipation of light energy and a decrease in Pn.


2009 ◽  
Vol 147 (4) ◽  
pp. 423-436 ◽  
Author(s):  
Z. C. ZHANG ◽  
Y. G. XUE ◽  
Z. Q. WANG ◽  
J. C. YANG ◽  
J. H. ZHANG

SUMMARYGrain filling is an intensive transportation process regulated by plant hormones. The present study investigated whether and how the interaction between abscisic acid (ABA) and ethylene is involved in mediating the grain filling of rice (Oryza sativaL.) under non-flooded mulching cultivation. A field experiment repeated over 2 years was conducted with two high-yielding rice cultivars, Zhendao 88 (ajaponicacultivar) and Shanyou 63 (anindicahybrid cultivar), and four cultivation treatments were imposed from transplanting to maturity: traditional flooding as control (TF), non-flooded plastic film mulching (PM), non-flooded wheat straw mulching (SM) or non-flooded no mulching (NM). Compared with that under TF, grain yield was reduced by 21·0–23·1% under PM (P<0·05), 1·4–1·8% under SM (P>0·05) and 50·9–55·4% under NM (P<0·05). Both PM and NM significantly (P<0·05) reduced the proportion of filled grains and grain weight and were associated with decreased grain filling rates. In SM there was a significant increase in the grain filling rate. The concentration of ABA in the grains was very low at the early grain filling stage, reaching a maximum when the grain filling rate was the highest, and showed no significant differences (P>0·05) between TF, PM and SM. However, it was significantly higher in NM. In contrast to ABA, the ethylene evolution rate and 1-aminocyclopropane-1-carboxylic acid (ACC) concentration in the grains were very high at the start of grain filling and sharply decreased during the active grain filling period. Both PM and NM increased the ethylene evolution rate and ACC concentration, whereas these were reduced in SM. The ratio of ABA to ACC was increased under SM but decreased under PM and NM, indicating that ethylene was more enhanced than ABA when plants were grown under NM and PM. The concentration of ABA correlated with the grain filling rate as a hyperbolic curve, whereas the ethylene evolution rate correlated with the grain filling rate as an exponential decay equation. The ratio of ABA to ACC significantly correlated with the grain filling rate with a linear relationship. Application of amino-ethoxyvinylglycine (inhibitor of ethylene synthesis by inhibiting ACC synthase) or ABA to panicles under TF and PM at the early grain filling stage significantly increased activities of the key enzymes involved in sucrose to starch conversion in the grains, sucrose synthase, ADP glucose pyrophosphorylase and soluble starch synthase, grain filling rate and grain weight. Application of ethephon (ethylene-releasing agent) or fluridone (inhibitor of ABA synthesis) had the opposite effect. The results suggest that antagonistic interactions between ABA and ethylene may be involved in mediating the effect of non-flooded mulching cultivation on grain filling, and a high ratio of ABA to ethylene enhances grain filling rate.


PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0255896
Author(s):  
Chongyang Li ◽  
Mingyang Ma ◽  
Tianpeng Zhang ◽  
Pengwen Feng ◽  
Xiao Chen ◽  
...  

Wheat (Triticum aestivum L.) is one of the most important crops in the world, but the yield and quality of wheat are highly susceptible to heat stress, especially during the grain-filling stage. Therefore, it is crucial to select high-yield and high-temperature-resistant varieties for food cultivation. There is a positive correlation between the yield and photosynthetic rate of wheat during the entire grain-filling stage, but few studies have shown that lines with high photosynthetic rates can maintain higher thermotolerance at the same time. In this study, two pairs of wheat near isogenic lines (NILs) with different photosynthetic rates were used for all experiments. Our results indicated that under heat stress, lines with a high photosynthetic rate could maintain the activities of photosystem II (PSII) and key Calvin cycle enzymes in addition to their higher photosynthetic rates. The protein levels of D1 and HSP70 were significantly increased in the highly photosynthetic lines, which contributed to maintaining high photosynthetic rates and ensuring the stability of the Calvin cycle under heat stress. Furthermore, we found that lines with a high photosynthetic rate could maintain high antioxidant enzyme activity to scavenge reactive oxygen species (ROS) and reduce ROS accumulation better than lines with a low photosynthetic rate under high-temperature stress. These findings suggest that lines with high photosynthetic rates can maintain a higher photosynthetic rate despite heat stress and are more thermotolerant than lines with low photosynthetic rates.


1996 ◽  
Vol 23 (2) ◽  
pp. 201 ◽  
Author(s):  
R Savin ◽  
ME Nicolas

Short periods (3-5 days) of high maximum temperature (>35�C), often accompanied by drought, commonly occur during grain filling of cereals. Short periods of high temperature have been shown to reduce grain weight and baking quality in wheat, but little is known about their effects on barley. Consequently, we examined the effects of high temperature and drought, alone or combined, on grain growth for two barley cultivars, Schooner and Franklin. Treatments started 15 days after anthesis and consisted of the factorial combination of three temperatures and three water regimes. The high temperature (maximum 40�C for 6 h day-1) and drought treatments were maintained for 5 or 10 days. Drought reduced individual grain weight much more (ca 20%) than high temperature (ca 5%) for both cultivars. Franklin appeared to be more sensitive to heat stress than Schooner. The reduction in individual grain weight was greatest when both stresses were combimed (ca 30%). The reduction in mature grain weight under high temperature was due to a reduction in duration of grain growth for Schooner and to a reduction in both rate and duration of grain growth for Franklin (8-12%). The reduction in duration of grain growth was the most important cause of reduced grain weight at maturity under drought alone (12-25%) or combined with high temperature (25-33%). Nitrogen content per grain was quite high and similar for all treatments, and nitrogen percentage increased when stress was severe enough to reduce starch accumulation, confirming that starch accumulation is more sensitive to post- anthesis stress than nitrogen accumulation. We conclude that drought, particularly when combined with high temperature, is more likely than heat stress to cause large reductions in grain weight of barley under field conditions.


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