Source-to-sink relationship between green leaves and green pseudobulbs of C&lt;sub&gt;3&lt;/sub&gt; orchid in regulation of photosynthesis

He, Junyu; Tan, Boon-Keat; Qin, Lin

doi:10.1007/s11099-011-0023-1

Cited by 30 publications

(30 citation statements)

References 27 publications

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“…There was no significant difference in F v /F m ratio for either acute or chronic heat stressed plants across all six vegetables, showing that dynamic PSII photoinhibition was rather mild [27]. This is either due to the lower solar irradiation in the greenhouse (maximum PPFD circa 500 µmol•m survival and daily maintenance of physiological processes [34]- [36].…”

Section: Chronic Stress Response Vs Acute Stress Responsementioning

confidence: 84%

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Physiological Performances of Temperate Vegetables with Response to Chronic and Acute Heat Stress

Lai¹,

He²

2016

AJPS

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In face of climate change catastrophes, understanding the thermal limits and optimal physiological thermal window food crop is of particular urgency. This research aims to evaluate: 1) how physiological performances of plant will change with increasing chronic and acute heat stress; 2) if the examined parameters form a hierarchy in terms of thermal tolerance; and 3) the optimal thermal window and critical temperatures of the examined plants with response to chronic and acute heat stress. Six temperate vegetables were subjected to chronic and acute heat stress and a suite of physiological parameters were evaluated. Dose responses were observed in shoot fresh weight, photosynthetic gas exchange, photosynthetic oxygen evolution, electron transfer rate, photo-and non-photochemical quenching with significant drop in performance as early as 28˚C for selected species. Conversely, ratio of variable to maximum fluorescence (F v /F m ) was not affected by heat stress until 46˚C in chronic heat stress. Examining the temperature at which a measured parameter's performance dropped by 50% compared to control (LT 50 ), a distinct hierarchy of the indices was observed for Canasta, recombinant inbred line 141, Lactuca serriola and Lactuca sativa (L. "Salinas"): shoot fresh weight, representing the highest integrated level of photosynthesis was the most sensitive to thermal stress (28˚C -30˚C), followed by oxygen evolution (35˚C -45˚C) while non-photochemical and photochemical quenching which is subcellular function of stress alleviation had a much higher capacity failure temperature (47˚C -60˚C). It is expected that F v /F m ratio, a measurement of sub-cellular structural integrity, will approach that of non-photochemical and photochemical quenching, if not exceeding it. By examining the photosynthetic parameters via their hierarchy of biological organization, it can be inferred that plants like Arugula and recombinant inbred line 192 are already operating near their thermal limit and have less energetic investment into heat stress mediation whereas L. serriola prioritizes thermal tolerance at the expense of photosynthesis efficiency.

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Section: Chronic Stress Response Vs Acute Stress Responsementioning

confidence: 84%

“…Decrease in g s sat indicates a CO 2 decrease at the chloroplast level due to stomatal closure which could result in stomatal limitation of photosynthesis (e.g. [27] [31]- [33]). As such, this translates to reduced plant growth due to impairment of photosynthesis.…”

Section: Chronic Stress Responsementioning

confidence: 99%

Physiological Performances of Temperate Vegetables with Response to Chronic and Acute Heat Stress

Lai¹,

He²

2016

AJPS

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“…Via the Imaging-PAM Chl Fluorometer (Walz, Effeltrich, Germany), images of fluorescence emission were digitized within the camera and transmitted via a Firewire interface (400 megabits/s) (Firewire-1394, Austin, TX, USA) to a personal computer for storage and analysis. Measurements and calculations of qP, qN and ETR were determined according to He et al [17].…”

Section: Measurements Of Photochemical Quenching (Qp) Non-photochemimentioning

confidence: 99%

Effects of Root-Zone Temperature on Photosynthesis, Productivity and Nutritional Quality of Aeroponically Grown Salad Rocket (<i>Eruca sativa</i>) Vegetable

He¹,

See²,

Qin³

et al. 2016

AJPS

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Although tropical high ambient temperature and humidity severely reduced the productivity of temperate plants, temperate vegetable crops such as lettuce have been successfully grown in Singapore by only cooling its root-zone. In this paper, a cool Meditteranean vegetable, Eruca sativa, was studied to understand how different RZTs can impact its shoot productivity, photosynthesis and nutritional quality. All plants were cultivated using aeroponic systems in a tropical greenhouse under hot ambient conditions where roots were subjected to four different root-zone temperatures (RZTs) of 20˚C-RZT, 25˚C-RZT, 30˚C-RZT and fluctuating ambient temperatures ranged from 25˚C to 38˚C [25˚C/38˚C (ambient)]-RZT. Parameters studied include shoot fresh weight (FW), photosynthetic gas exchange, midday chlorophyll (Chl) fluorescence F v /F m ratio, Chl fluorescence photochemical quenching (qP), non-photochemical quenching (qN) and electron transport rate (ETR), total phenolic compounds and mineral content such as potassium (K), calcium (Ca), magnesium (Mg) and iron (Fe). Among the 4 different RZT treatments, E. sativa plants grown under ambient-RZT (25/38˚C-RZT) had the lowest shoot and root FW while those plants grown under 20˚C-RZT had highest productivity of shoot and root. However, there were no significant differences in shoot and root FW in plants grown at 25˚Cand 30˚C-RZT. Compared to plants grown under 25˚C/38˚C (ambient-RZT), lightsaturated photosynthetic CO 2 assimilation rate (A sat ) and stomatal conductance (g ssat ) were similarly higher in 20˚C-, 25˚C-and 30˚C-RZT. All plants had midday Chl fluorescence F v /F m ratio lower than <0.8 ranged from 0.785 to 0.606 with the highest and lowest ratios recorded in 20˚C-RZT and ambient-RZT plants, respectively. These results indicate that cooling the RZ of E. sativa plants protected their PS II from photoinactivation during midday in the greenhouse. There were no significant dif-How to cite this paperOpen Access J. He et al. 1994 ferences observed in photochemical quenching (qP), non-photochemical quenching (qN) and electron transport rate among plants grown under 20˚C-, 25˚C-and 30˚C-RZT. However, plants grown under ambient-RZT had lower qP, qN and ETR compared to all other plants. E. sativa at 20˚C-RZT with the best developed roots had the highest dietary mineral (K, Mg, Ca and Fe) contents but lower total phenolics content. In contrast, ambient-RZT, plants with poorly developed roots had the lowest mineral content but highest total phenolic content. The results of this study suggest that cooling of roots is a feasible method for the cultivation of E. sativa in the tropic, which enhances the content of dietary minerals in shoots.

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“…ETR, qP and NPQ were determined using the Imaging Pam Chl Fluorometer (Walz, Effeltrich, Germany) at 25˚C under different PPFDs in the laboratory as described by He et al [17]. By using the PAM Chl Fluorometer, images of fluorescence emission were digitized within the camera and via a Firewire interface (400 megabits/s) (Firewire-1394, Austin, TX, USA) to a personal computer for storage and analysis.…”

Section: Measurement Of Electron Transport Rate (Etr) Photochemicalmentioning

confidence: 99%

Photosynthetic Capacities and Productivity of Indoor Hydroponically Grown <i>Brassica alboglabra</i> Bailey under Different Light Sources

He¹,

Qin²,

Liu³

et al. 2015

AJPS

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A major challenge for growing vegetables in an indoor vertical farming system will be supplying not only sufficient quantity but also quality of light. It has been reported that yield of crops is enhanced under appropriate combination of red and blue light compared with red light alone. This project aims to investigate the effects of different combinations of red and blue. Plants were cultured for a 12-h photoperiod at 210 µmol•m -2 •s -1 photosynthetic photon flux density (PPFD) under different combinations of red (R) and blue (B) light-emitting diodes (LED). The R:B-LED ratios are: 1) 100:0 (0B); 2) 92:8 (8B); 3) 84:16 (16B) and; 4) 76:24 (24B). All combined RB-LEDs significantly increased light-saturated photosynthetic CO2 assimilation rate (Asat), stomatal conductance (gs sat) and productivity compared with those under 0B. Results suggested that 16B was the most suitable combination of LEDs to achieve the highest productivity for B. alboglabra. To further substantiate these results, comparative studies were conducted under equal photoperiod and PPFD among 16B (RB-LED), white LED (RBW-LED) and high-pressure sodium (HPS) lamps. Shoot, root biomass, leaf number, leaf mass per area and Asat were higher in plants under HPS lamps and RB-LED, than under RBW-LED. However, gs sat was lower under RB-LED and RBW-LED, than under HPS lamps. Plants under RB-LED had higher electron transport rate and photochemical quenching but lower non-photochemical quenching than those under RBW-LED and HPS lamps. Thus, these results more conclusively affirmed that 16B was the most suitable light source to achieve the highest photosynthetic capacities. The findings of this study could also be used in vertical farming to achieve the highest productivity of vegetable crops such as B. alboglabra within the shortest growth cycle with reduced energy consumption.

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Source-to-sink relationship between green leaves and green pseudobulbs of C<sub>3</sub> orchid in regulation of photosynthesis

Cited by 30 publications

References 27 publications

Physiological Performances of Temperate Vegetables with Response to Chronic and Acute Heat Stress

Physiological Performances of Temperate Vegetables with Response to Chronic and Acute Heat Stress

Effects of Root-Zone Temperature on Photosynthesis, Productivity and Nutritional Quality of Aeroponically Grown Salad Rocket (<i>Eruca sativa</i>) Vegetable

Photosynthetic Capacities and Productivity of Indoor Hydroponically Grown <i>Brassica alboglabra</i> Bailey under Different Light Sources

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Source-to-sink relationship between green leaves and green pseudobulbs of C<sub>3</sub> orchid in regulation of photosynthesis

Cited by 30 publications

References 27 publications

Physiological Performances of Temperate Vegetables with Response to Chronic and Acute Heat Stress

Physiological Performances of Temperate Vegetables with Response to Chronic and Acute Heat Stress

Effects of Root-Zone Temperature on Photosynthesis, Productivity and Nutritional Quality of Aeroponically Grown Salad Rocket (&lt;i&gt;Eruca sativa&lt;/i&gt;) Vegetable

Photosynthetic Capacities and Productivity of Indoor Hydroponically Grown &lt;i&gt;Brassica alboglabra&lt;/i&gt; Bailey under Different Light Sources

Contact Info

Product

Resources

About

Effects of Root-Zone Temperature on Photosynthesis, Productivity and Nutritional Quality of Aeroponically Grown Salad Rocket (<i>Eruca sativa</i>) Vegetable

Photosynthetic Capacities and Productivity of Indoor Hydroponically Grown <i>Brassica alboglabra</i> Bailey under Different Light Sources