scholarly journals Interactive Effects of Intraspecific Competition and Drought on Stomatal Conductance and Hormone Concentrations in Different Tomato Genotypes

Horticulturae ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 45
Author(s):  
Yang Gao ◽  
Yueping Liang ◽  
Yuanyuan Fu ◽  
Zhuanyun Si ◽  
Abdoul Kader Mounkaila Hamani

Plant physiological responses to various stresses are characterized by interaction and coupling, while the intrinsic mechanism remains unclear. The effects of intraspecific competition on plant growth, stomatal opening, and hormone concentrations were investigated with three tomato genotypes (WT-wild type, Ailsa Craig; FL-a abscisic acid (ABA) deficient mutant, flacca; NR-a partially ethylene-insensitive genotype) under two water regimes (full irrigation, irrigation amount = daily transpiration; deficit irrigation, 60% of irrigation amount in full irrigation) in this study. Three kinds of competitions were designed, i.e., root and canopy competition, non-root competition, and non-canopy competition, respectively. Intraspecific competition reduced plant leaf area and stomatal conductance (gs) of wild-type tomato, accompanied by ABA accumulation and ethylene evolution. Intraspecific competition-induced decrease in gs was absent in FL and NR, indicating ABA and ethylene involved in plant response to intraspecific competition. As soil water becomes dry, the competition decreased gs by elevating ABA and ethylene accumulations. Under severe drought, the competition-induced decline in gs was covered by the severe drought-induced decrease in gs, as hydraulic signals most probably dominate. The absence of canopy competition insignificantly influenced plant stomatal opening of well-watered tomato, as canopy separation minimized the plant neighbor sensing by ethylene and other signals. Whereas under water deficit condition, the absence of canopy competition significantly reduced ABA accumulation in roots and then stomatal conductance, indicating the belowground neighbor detection signals maybe enhanced by soil drought. The absence of root competition increased ethylene evolution, confirming the importance of ethylene in neighbor detection and plant response to environmental stress.

2021 ◽  
Author(s):  
Yang Gao ◽  
Yueping Liang ◽  
Shuang Li ◽  
Zhuanyun Si ◽  
Abdoul.Kader.Mounkaila Hamani

Abstract We elucidated the effects of intraspecific competition on plant growth, stomatal opening and hormone concentrations in different tomato genotypes under different water regimes. Intraspecific competition reduced plant leaf area and stomatal conductance (gs) of wild-type tomato (Ailsa Craig), which was accompanied by abscisic acid (ABA) accumulation and ethylene evolution. Intraspecific competition-induced decrease in gs was absent in flacca, an ABA-deficient mutant, and in never-ripe, a partially ethylene-insensitive genotype, indicating ABA and ethylene involved in plant response to intraspecific competition. As soil water becomes dry, the competition decreased gs by elevating ABA and ethylene accumulations. Under severe drought, the competition-induced decline in gs was covered by the severe drought-induced decrease in gs, as hydraulic signals most probably dominate. Absence of canopy competition had no significant influence on plant stomatal opening of well-watered tomato, due to canopy separation minimized the plant neighbor sensing by ethylene and other signals. Whereas under water deficit condition, absence of canopy competition significantly reduced ABA accumulation in roots and then stomatal conductance, indicating the belowground neighbour detection signals maybe enhanced by soil drought. Absence of root competition increased ethylene evolution, confirming the importance of ethylene in neighbor detection and plant response to environmental stress.


2020 ◽  
Author(s):  
Ivana Petrović ◽  
Zorica Jovanović ◽  
Radmila Stikić ◽  
Milena Marjanović ◽  
Slađana Savić

2020 ◽  
Vol 71 (7) ◽  
pp. 2339-2350 ◽  
Author(s):  
Haruki Kimura ◽  
Mimi Hashimoto-Sugimoto ◽  
Koh Iba ◽  
Ichiro Terashima ◽  
Wataru Yamori

Abstract It has been reported that stomatal conductance often limits the steady-state photosynthetic rate. On the other hand, the stomatal limitation of photosynthesis in fluctuating light remains largely unknown, although in nature light fluctuates due to changes in sun position, cloud cover, and the overshadowing canopy. In this study, we analysed three mutant lines of Arabidopsis with increased stomatal conductance to examine to what extent stomatal opening limits photosynthesis in fluctuating light. The slac1 (slow anion channel-associated 1) and ost1 (open stomata 1) mutants with stay-open stomata, and the PATROL1 (proton ATPase translocation control 1) overexpression line with faster stomatal opening responses exhibited higher photosynthetic rates and plant growth in fluctuating light than the wild-type, whereas these four lines showed similar photosynthetic rates and plant growth in constant light. The slac1 and ost1 mutants tended to keep their stomata open in fluctuating light, resulting in lower water-use efficiency (WUE) than the wild-type. However, the PATROL1 overexpression line closed stomata when needed and opened stomata immediately upon irradiation, resulting in similar WUE to the wild-type. The present study clearly shows that there is room to optimize stomatal responses, leading to greater photosynthesis and biomass accumulation in fluctuating light in nature.


2011 ◽  
Vol 63 (4) ◽  
pp. 1167-1171 ◽  
Author(s):  
Ljiljana Prokic ◽  
Radmila Stikic

The effects of drought and partial root drying (PRD) on shoot and root growth was assessed in the wild type Ailsa Craig (WT) and the flacca tomato mutant deficient in the plant hormone ABA. Our results show that drought had an inhibitory effect on shoot growth in flacca and especially in WT; the most profound effect was observed in FI (full irrigation), then PRD and the smallest in D plants. Root development in both WT and flacca was stimulated after the 3rd day of the experiment following a decrease in the soil water content. On the 11th day of the experiment, when the soil water content was reduced by about 50% of full irrigation (FI), the root density was increased in the drying part of the PDR and on both sides of the drought treatment. On the basis of these results it can be assumed that increased root density and root length represent an adaptation or root adjustment to drought conditions.


2021 ◽  
Vol 12 ◽  
Author(s):  
Shigeo Toh ◽  
Naoki Takata ◽  
Eigo Ando ◽  
Yosuke Toda ◽  
Yin Wang ◽  
...  

Stomata in the plant epidermis open in response to light and regulate CO2 uptake for photosynthesis and transpiration for uptake of water and nutrients from roots. Light-induced stomatal opening is mediated by activation of the plasma membrane (PM) H+-ATPase in guard cells. Overexpression of PM H+-ATPase in guard cells promotes light-induced stomatal opening, enhancing photosynthesis and growth in Arabidopsis thaliana. In this study, transgenic hybrid aspens overexpressing Arabidopsis PM H+-ATPase (AHA2) in guard cells under the strong guard cell promoter Arabidopsis GC1 (AtGC1) showed enhanced light-induced stomatal opening, photosynthesis, and growth. First, we confirmed that AtGC1 induces GUS expression specifically in guard cells in hybrid aspens. Thus, we produced AtGC1::AHA2 transgenic hybrid aspens and confirmed expression of AHA2 in AtGC1::AHA2 transgenic plants. In addition, AtGC1::AHA2 transgenic plants showed a higher PM H+-ATPase protein level in guard cells. Analysis using a gas exchange system revealed that transpiration and the photosynthetic rate were significantly increased in AtGC1::AHA2 transgenic aspen plants. AtGC1::AHA2 transgenic plants showed a>20% higher stem elongation rate than the wild type (WT). Therefore, overexpression of PM H+-ATPase in guard cells promotes the growth of perennial woody plants.


2006 ◽  
Vol 33 (11) ◽  
pp. 1037 ◽  
Author(s):  
Dirk Büssis ◽  
Uritza von Groll ◽  
Joachim Fisahn ◽  
Thomas Altmann

Stomatal density of transgenic Arabidopsis thaliana plants over-expressing the SDD1 (stomatal density and distribution) gene was reduced to 40% and in the sdd1-1 mutant increased to 300% of the wild type. CO2 assimilation rate and stomatal conductance of over-expressers and the sdd1-1 mutant were unchanged compared with wild types when measured under the light conditions the plants were exposed to during growth. Lower stomatal density was compensated for by increased stomatal aperture and conversely, increased stomatal density was compensated for by reduced stomatal aperture. At high light intensities the assimilation rates and stomatal conductance of SDD1 over-expressers were reduced to 80% of those in wild type plants. Areas beneath stomata and patches lacking stomata were analysed separately. In areas without stomata, maximum fluorescence yield (Fv / Fm) and quantum yield of photosystem II (Φ PSII) were significantly lower than in areas beneath stomata. In areas beneath stomata, Fv / Fm and Φ PSII were identical to levels measured in wild type leaves. At high light intensities over-expressers showed decreased photochemical quenching (qP) compared with wild types. However, the decrease of qP was significantly stronger in areas without stomata than in mesophyll areas beneath stomata. At high CO2 partial pressures and high light intensities CO2 assimilation rates of SDD1 over-expressers did not reach wild type levels. These results indicate that photosynthesis in SDD1 over-expressers was reduced because of limiting CO2 in areas furthest from stomata at high light.


2021 ◽  
Author(s):  
Qiuzhu Wang ◽  
Lin Zhang ◽  
Shushen Yang

Abstract Backgrounds: Wheat (Triticum aestivum L.) is one of the most important food crops in the world. It faces various abiotic stresses during its growth. Drought is one of the main factors limiting the growth and development of wheat. Severe drought stress will Lead to a decline in wheat production. Cytoplasmic glyceraldehyde-3-phosphate dehydrogenase (GAPC) is an important member of the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) family, which is widely present in plant cytoplasm. Plants play an important role in the process of primary metabolism and stress resistance.Result: In this study, a comparative transcriptomic analysis of the TaGAPCs-RNAi strain of Changwu 134 and the wild-type wheat seedlings of Changwu 134 under natural drought conditions was carried out. A total of 30067 differentially expressed genes were screened in RNAi strains and wild-type strains, of which 19,959 genes were up-regulated in RNAi strains and 10,108 genes were down-regulated in transcription. GO analysis shows that differential genes are mainly enriched in biological regulation, cellular processes, metabolic processes, and responses to stimuli. KEGG analysis showed that the differential genes were mainly concentrated in the biosynthesis of phenylpropane, plant hormone signal transduction and flavonoid biosynthesis pathways. By analyzing the expression levels of differential transcription factors, the significantly down-regulated transcription factor WRKY family member TaWRKY2 / 22/28/29/33/40/47/52 in wheat was screened out. The TaWRKY28/33/40/47 gene silencing line was successfully obtained using the barley stripe mosaic virus (BSMV-VIGS) technology. The plants with TaWRKY28/33/40/47 gene silenced were subjected to natural drought treatment, and physiological and biochemical index tests were carried out. The results showed that the growth status of gene-silenced plants was worse than that of wild-type plants, and the relative water content and chlorophyll content decreased. The content of MDA, H2O2 and superoxide anion increases, the activity of antioxidant enzymes (SOD, POD, CAT) decreases, and the content of proline decreases. Conclusion: The results showed that TaGAPCs regulates the expression of some TaWRKYs transcription factors, activates antioxidant pathways, enhances tolerance of wheat to drought stress.


2003 ◽  
Vol 30 (7) ◽  
pp. 777 ◽  
Author(s):  
Ian C. Dodd

The ABA-deficient wilty pea (Pisum sativum L.) and its wild-type (WT) were grown at two levels of nitrogen supply (0.5 and 5.0 mM) for 5–6 weeks from sowing, to determine whether leaf ABA status altered the leaf growth response to N deprivation. Plants were grown at high relative humidity to prevent wilting of the wilty peas. Irrespective of N supply, expanding wilty leaflets had ca 50% less ABA than WT leaflets but similar ethylene evolution rates. Fully expanded wilty leaflets had lower relative water contents (RWC) and were 10–60% smaller in area (according to the node of measurement) than WT leaflets. However, there were no genotypic differences in plant relative leaf expansion rate (RLER). Growth of both genotypes at 0.5 mM N increased the RWC of fully expanded leaflets, but did not alter ethylene evolution or ABA concentration of expanding leaflets. Plants grown at 0.5 mM N showed a 20–30% reduction in RLER, which was similar in magnitude in both wilty and WT peas. Thus,�leaf ABA status did not alter the leaf growth response to N deprivation.


2007 ◽  
Vol 85 (2) ◽  
pp. 148-159 ◽  
Author(s):  
Mirwais M. Qaderi ◽  
M. Anisul Islam ◽  
David M. Reid ◽  
Saleh Shah

Few studies have considered ethylene involvement in plant responses to ultraviolet-B (UVB) radiation. We studied the responses to UVB radiation of one wild-type (WT, ‘Westar’) canola (Brassica napus L.) with normal ethylene evolution and two transgenic (C1, C2) lines with lower ethylene evolution. Canola plants were grown under biologically effective levels of UVB (UVBBE) radiation: 0.03 (low), 4.88 (medium), and 9.78 (high) kJ·m–2·d–1 in controlled-environment growth chambers. The growth and physiological parameters of the plants were measured. Of the two transgenic lines, C1 demonstrated higher ethylene evolution than C2 but lower than WT. The lowest aboveground and belowground biomass was found with exposure to high UVB radiation. WT produced more biomass than C2. Net CO2 assimilation and transpiration did not vary among plant lines or UVB treatments. Water-use efficiency was lower under high UVB radiation than under low UVB. The quantum yield of photosystem II was higher for C2 than for either WT or C1. WT did not differ from transgenic plants in respect to photosynthetic pigments and UV-screening compounds. Photosynthetic pigment concentration decreased, but concentration of UV-screening compounds, thickness of epicuticular wax, and the rate of root hydraulic conductance were increased by exposure to UVB radiation. While there appears to be a lack of ethylene involvement in some of the measured physiological parameters, the transgenic plants exhibited differential sensitivity to UVB in a few key measured parameters.


Author(s):  
Leonard Gol ◽  
Einar B Haraldsson ◽  
Maria von Korff

Abstract Drought impairs growth and spike development, and is therefore a major cause of yield losses in the temperate cereals barley and wheat. Here, we show that the photoperiod response gene PHOTOPERIOD-H1 (Ppd-H1) interacts with drought stress signals to modulate spike development. We tested the effects of a continuous mild and a transient severe drought stress on developmental timing and spike development in spring barley cultivars with a natural mutation in ppd-H1 and derived introgression lines carrying the wild-type Ppd-H1 allele from wild barley. Mild drought reduced the spikelet number and delayed floral development in spring cultivars but not in the introgression lines with a wild-type Ppd-H1 allele. Similarly, drought-triggered reductions in plant height, and tiller and spike number were more pronounced in the parental lines compared with the introgression lines. Transient severe stress halted growth and floral development; upon rewatering, introgression lines, but not the spring cultivars, accelerated development so that control and stressed plants flowered almost simultaneously. These genetic differences in development were correlated with a differential down-regulation of the flowering promotors FLOWERING LOCUS T1 and the BARLEY MADS-box genes BM3 and BM8. Our findings therefore demonstrate that Ppd-H1 affects developmental plasticity in response to drought in barley.


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