scholarly journals Plant buffering against the high-light stress-induced accumulation of CsGA2ox8 transcripts via alternative splicing to finely tune gibberellin levels and maintain hypocotyl elongation

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Bin Liu ◽  
Shuo Zhao ◽  
Pengli Li ◽  
Yilu Yin ◽  
Qingliang Niu ◽  
...  

AbstractIn plants, alternative splicing (AS) is markedly induced in response to environmental stresses, but it is unclear why plants generate multiple transcripts under stress conditions. In this study, RNA-seq was performed to identify AS events in cucumber seedlings grown under different light intensities. We identified a novel transcript of the gibberellin (GA)-deactivating enzyme Gibberellin 2-beta-dioxygenase 8 (CsGA2ox8). Compared with canonical CsGA2ox8.1, the CsGA2ox8.2 isoform presented intron retention between the second and third exons. Functional analysis proved that the transcript of CsGA2ox8.1 but not CsGA2ox8.2 played a role in the deactivation of bioactive GAs. Moreover, expression analysis demonstrated that both transcripts were upregulated by increased light intensity, but the expression level of CsGA2ox8.1 increased slowly when the light intensity was >400 µmol·m−2·s−1 PPFD (photosynthetic photon flux density), while the CsGA2ox8.2 transcript levels increased rapidly when the light intensity was >200 µmol·m−2·s−1 PPFD. Our findings provide evidence that plants might finely tune their GA levels by buffering against the normal transcripts of CsGA2ox8 through AS.

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Maral Hosseinzadeh ◽  
Sasan Aliniaeifard ◽  
Aida Shomali ◽  
Fardad Didaran

Abstract Biomass partitioning is one of the pivotal determinants of crop growth management, which is influenced by environmental cues. Light and CO2 are the main drivers of photosynthesis and biomass production in plants. In this study, the effects of CO2 levels: ambient 400 ppm (a[CO2]) and elevated to 1,000 ppm (e[CO2]) and different light intensities (75, 150, 300, 600 μmol·m−2·s−1 photosynthetic photon flux density – PPFD) were studied on the growth, yield, and biomass partitioning in chrysanthemum plants. The plants grown at higher light intensity had a higher dry weight (DW) of both the vegetative and floral organs. e[CO2] diminished the stimulating effect of more intensive light on the DW of vegetative organs, although it positively influenced inflorescence DW. The flowering time in plants grown at e[CO2] and light intensity of 600 μmol·m−2·s−1 occurred earlier than that of plants grown at a[CO2]. An increase in light intensity induced the allocation of biomass to inflorescence and e[CO2] enhanced the increasing effect of light on the partitioning of biomass toward the inflorescence. In both CO2 concentrations, the highest specific leaf area (SLA) was detected under the lowest light intensity, especially in plants grown at e[CO2]. In conclusion, elevated light intensity and CO2 direct the biomass toward inflorescence in chrysanthemum plants.


2020 ◽  
Vol 10 (3) ◽  
pp. 1044
Author(s):  
Xiangnan Xu ◽  
Ricardo Hernández

Open-field strawberry propagation is faced with several challenges such as lack of daughter plants, low quality, and disease transmission. Propagating strawberry plants in a completely enclosed controlled environment using a precision indoor propagation (PIP) system could overcome some of the challenges seen in open-field strawberry propagation. Optimizing the light intensity in a PIP system improves plant growth and reduce propagation cost. In the present study, “Albion” strawberry plants were grown as stock plants in a PIP system to examine plant propagation efficacy under three light intensities, PPF-250 (241 ± 13), PPF-350 (337 ± 13), or PPF-450 (443 ± 17) photosynthetic photon flux density (PPFD, μmol m−2 s−1) at 12 h photoperiod. They were grown under 25.7 ± 0.05 °C temperature, 0.95 ± 0.04 kPa vapor pressure deficit, and 73% ± 5.2% relative humidity. The number of daughter plants, morphology, and growth were recorded weekly (non-destructive measurements) for two intervals (01 to 12 weeks and 12 to 21 weeks). The number, total dry mass, and total fresh mass of daughter plants per stock plant increased with the increase in light intensity. The propagation efficacy to light ranged between 0.3 and 1.9 daughter plants per mole of light, depending on light intensity and harvest time. The number of daughter plants per week was estimated to be 36.2 plants wk−1 m−2. Daughter plants were classified by size and size was not influenced by the light treatment. Stock plant crown diameter, leaf area, fresh mass, dry mass, and leaf count all increased with an increase in PPFD. The shoot dry mass percent distribution to the daughter plant was 45% to 46% and was not affected by light intensity treatment. This study demonstrates the feasibility of using PIP systems for the production of strawberry daughter plants.


Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 537
Author(s):  
Meifang Gao ◽  
Rui He ◽  
Rui Shi ◽  
Yiting Zhang ◽  
Shiwei Song ◽  
...  

To produce high-quality broccoli microgreens, suitable light intensity for growth and phytochemical contents of broccoli microgreens in an artificial light plant factory were studied. Broccoli microgreens were irradiated under different photosynthetic photon flux density (PPFD): 30, 50, 70 and 90 μmol·m−2·s−1 with red: green: blue = 1:1:1 light-emitting diodes (LEDs). The broccoli microgreens grown under 50 μmol·m−2·s−1 had the highest fresh weight, dry weight, and moisture content, while the phytochemical contents were the lowest. With increasing light intensity, the chlorophyll content increased, whereas the carotenoid content decreased. The contents of soluble protein, soluble sugar, free amino acid, flavonoid, vitamin C, and glucosinolates except for progoitrin in broccoli microgreens were higher under 70 μmol·m−2·s−1. Overall, 50 μmol·m−2·s−1 was the optimal light intensity for enhancement of growth of broccoli microgreens, while 70 μmol·m−2·s−1 was more feasible for improving the phytochemicals of broccoli microgreens in an artificial light plant factory.


Agronomy ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 339 ◽  
Author(s):  
Hao Wei ◽  
Jin Zhao ◽  
Jiangtao Hu ◽  
Byoung Ryong Jeong

Lower quality and longer production periods of grafted seedlings, especially grafted plug seedlings of fruit vegetables, may result from insufficient amounts of light, particularly in rainy seasons and winter. Supplemental artificial lighting may be a feasible solution to such problems. This study was conducted to evaluate light intensity’s influence on the quality of grafted tomato seedlings, ‘Super Sunload’ and ‘Super Dotaerang’ were grafted onto the ‘B-Blocking’ rootstock. To improve their quality, grafted seedlings were moved to a glasshouse and grown for 10 days. The glasshouse had a combination of natural lighting from the sun and supplemental lighting from LEDs (W1R2B2) for 16 h/day. Light intensity of natural lighting was 490 μmol·m−2·s−1 photosynthetic photon flux density (PPFD) and that of supplemental lighting was 50, 100, or 150 μmol·m−2·s−1 PPFD. The culture environment had 30/25 °C day/night temperatures, 70% ± 5% relative humidity (RH), and a natural photoperiod of 14 h as well. Compared with quality of seedlings in supplemental lighting of 50 μmol·m−2·s−1 PPFD, that of seedlings in supplement lighting of 100 or 150 μmol·m−2·s−1 PPFD improved significantly. With increasing light intensity, diameter, fresh weight, and dry weight, which were used to measure shoot growth, greatly improved. Leaf area, leaf thickness, and root biomass were also greater. However, for quality of seedlings, no significant differences were discovered between supplement lighting of 100 μmol·m−2·s−1 PPFD and supplement lighting of 150 μmol·m−2·s−1 PPFD. Expressions of PsaA and PsbA (two photosynthetic genes) as well as the corresponding proteins increased significantly in supplement lightning of 100 and 150 μmol·m−2·s−1 PPFD, especially in 100 μmol·m−2·s−1 PPFD. Overall, considering quality and expressions of two photosynthetic genes and proteins, supplemental light of 100 μmol·m−2·s−1 PPFD (W1R2B1) would be the best choice to cultivate grafted tomato seedlings.


Agronomy ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2549
Author(s):  
Chia-Man Chang ◽  
Kuan-Hung Lin ◽  
Meng-Yuan Huang ◽  
Chung-I Chen ◽  
Mei-Li Hsueh ◽  
...  

Oncidium are grown worldwide and play important economic roles. The objective of this study was to investigate the pseudobulb growth and flowering characteristics of the two Oncidesa Gower Ramsey cultivars, ‘Honey Angel (HA)’ and ‘Golden Star (GS)’, cultivated under 3 kinds of fertilizer treatments in response to 40% light intensity (LI-40) and 30% light intensity (LI-30, as control) photosynthetic photon flux density over a 5-month period. The conventional-fertilizer (CF) treatment, as a control, consisted of a liquid manure solution of N:K = 1:1.12, mixed with 7.8% N, 0.8% P2O5, 0.3% K2O, and 57.3% of organic matter that was foliage-applied to plants twice weekly. The stage-fertilizer (SF) treatment consisted of N:P:K = 1:1:5 foliage-applied to plants in an unsheathing pseudobulb stage until reaching inflorescence, followed by N:P:K = 1:1:1 application until the end of the experiment. The fortnight-fertilizer (FF) treatment consisted of N:P:K = 1:1:5 and N:P:K = 1:1:1 with interval-rotate foliage-application to plants weekly until the end of the experiment. Pseudobulb length (PL), pseudobulb major axis (PW), and pseudobulb minor axis (PT), and inflorescence length (FL), number of pedicel (FB), and floret numbers (FN) per plant were recorded and calculated from two months after pseudobulb maturity until the end of the five-month experimental period. The GS variety significantly increased PL when treated with CF and FF compared to HA, and GS treated with CF under LI-30 exhibited the longest PL at 81.65 mm. PW increased as LI increased under FF treatment, and the largest PW was observed in GS treated with FF under LI-40. A maximal and significant increase in PT occurred in LI-40 compared to LI-30 under the CF treatment. GS had a significantly higher FL compared to HA treated with CF, and the longest FL was detected in GS under LI-30. HA had a significantly higher FB and FN under LI-40 than under LI-30, and the highest number of FB and FN in HA occurred when it was treated with CF and SF, respectively. Precision management of fertilization treatments in response to LI can maximize pseudobulb growth, development, and flowering quality in Oncidesa species.


Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 490
Author(s):  
Tengyue Zou ◽  
Chuanhui Huang ◽  
Pengfei Wu ◽  
Long Ge ◽  
Yong Xu

Artificial LED source provides the possibility to regulate the lighting environment in plant factorys that use limited space to plant, aiming at high throughput and good quality. However, different parameters of light intensity, quality, and photoperiod will influence the growth and accumulation of bio-compounds in plants. In order to find the optimal setting of LED light for spinach planting, four group experiments were designed using the orthogonal testing method. According to the experimental results, for growth indexes including fresh weight, dry weight, root length and so on, photoperiod is the most influential factor, light intensity is the second, and light quality is the least. The best light mode (R:B = 4:1, photosynthetic photon flux density (PPFD) = 100 μmol∙m−2∙s−1 and 13/11 h) among all eight possible combinations in the range was also determined. Furthermore, for quality indexes, including the soluble sugar content, protein content and so on, a new scoring method was introduced to make a comprehensive score for evaluating. Then, the light combination (R:B = 4:1, PPFD = 150 μmol∙m−2∙s−1 and 9/15 h) in the range was found as the optimal scheme for spinach quality under those parameters. As there is trade-off between the optimal light parameters for growth and quality, it is necessary to achieve a balance between yield and quality of the plant during production. If farmers want to harvest spinach with larger leaf area and higher yield, they need to pay attention to the adjustment of the photoperiod and use a lower light intensity and a longer lighting time. If they do not mind the yield of the vegetable but want to improve the taste and nutrition of spinach products, they should pay more attention to the light intensity and use a higher light intensity and a shorter lighting time.


Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 344
Author(s):  
Md Momtazur Rahman ◽  
Mikhail Vasiliev ◽  
Kamal Alameh

Manipulation of the LED illumination spectrum can enhance plant growth rate and development in grow tents. We report on the identification of the illumination spectrum required to significantly enhance the growth rate of sweet basil (Ocimum basilicum L.) plants in grow tent environments by controlling the LED wavebands illuminating the plants. Since the optimal illumination spectrum depends on the plant type, this work focuses on identifying the illumination spectrum that achieves significant basil biomass improvement compared to improvements reported in prior studies. To be able to optimize the illumination spectrum, several steps must be achieved, namely, understanding plant biology, conducting several trial-and-error experiments, iteratively refining experimental conditions, and undertaking accurate statistical analyses. In this study, basil plants are grown in three grow tents with three LED illumination treatments, namely, only white LED illumination (denoted W*), the combination of red (R) and blue (B) LED illumination (denoted BR*) (relative red (R) and blue (B) intensities are 84% and 16%, respectively) and a combination of red (R), blue (B) and far-red (F) LED illumination (denoted BRF*) (relative red (R), blue (B) and far-red (F) intensities are 79%, 11%, and 10%, respectively). The photosynthetic photon flux density (PPFD) was set at 155 µmol m−2 s−1 for all illumination treatments, and the photoperiod was 20 h per day. Experimental results show that a combination of blue (B), red (R), and far-red (F) LED illumination leads to a one-fold increase in the yield of a sweet basil plant in comparison with only white LED illumination (W*). On the other hand, the use of blue (B) and red (R) LED illumination results in a half-fold increase in plant yield. Understanding the effects of LED illumination spectrum on the growth of plant sweet basil plants through basic horticulture research enables farmers to significantly improve their production yield, thus food security and profitability.


2016 ◽  
Vol 44 (2) ◽  
pp. 393-398
Author(s):  
Chang-Chang CHEN ◽  
Kuan-Hung LIN ◽  
Meng-Yuan HUANG ◽  
Wen-Dar HUANG ◽  
Chi-Ming YANG

The objective of this study was to investigate the dynamics of chlorophyll (Chl), biosynthetic intermediates (protoporphyrin IX, magnesium protoporphyrin IX, and protochlorophyllide), degradation intermediates [chlorophyllide (Chlide), pheophytin (Phe), and pheophorbide (Pho)], and carotenoids (Car) in leaves of rice seedlings. Two rice varieties, 'Taichung Shen 10' ('TCS10') and 'IR1552', were grown under different light quality conditions controlled by light emitting diodes (LED). Lighting treatments for rice seedlings were included by red (R), blue (B), green (G), and red + blue (RB), with fluorescent lighting (FL) as the control and photosynthetic photon flux density being set at 105 µmol m-2 s-1. The results show that lower levels of Chl and Car in leaves were detected under G lighting, and light quality did not mediate porphyrins in biosynthetic pathways. Rice seedling leaves took Chl→Phe→Pho and Chl→Chlide→Pho as the major and minor degradation routes, respectively. Furthermore, higher Phe/Chlide ratios were observed under G and FL lighting conditions, indicating that green-enriched environments can up-regulate the minor degradation route in leaves.


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