The generation of "electrical signals" in plants has always been regarded as a plant response mechanism to external environmental stresses, and is closely related to a large number of plant physiological and biochemical reactions, such as mimosa leaf movement, pin2 gene expression, and total protein synthesis. Inhibition, ethylene synthesis, abscisic acid and jasmonic acid synthesis, changes in root phosphate assimilation, reduced transport capacity of phloem, unloading of sieve molecules, increased nonspecific resistance of plants, etc. In recent years, studying the relationship between plant "electrical signals" and photosynthesis has gradually become the focus of attention. Among them, AP (action potential) and VP (potential change) have been the most studied, but in most cases, they are inconsistent.
A few days ago, Russian scientists used the portable photosynthesis-fluorescence measurement system GFS-3000 developed by the German WALZ company and the dual-channel PAM-100 measurement system Dual-PAM-100, using the "gas exchange-P700-chlorophyll fluorescence measurement technology", using the classic The "burning leaf method" stimulates plants to produce "electrical signals", supplemented by low CO2 concentration and low light treatment conditions, and simultaneously measures the relevant parameters of geranium gas exchange, chlorophyll fluorescence (PSII) and P700 (PSI), and comprehensively analyzes geranium Response of photosynthesis to VP. (Sukhov V et al., Analysis of the photosynthetic response induced by variation potential in geranium. Planta, 2011, in press)
It was found that under normal conditions, VP caused a reduction in geranium photosynthesis, which was mainly manifested by the fact that the actual quantum yields of PSI and PSII (φPSI, φPSII), CO2 assimilation rate (A), and stomatal conductance (GH2O) all decreased significantly, and the A large number of parameters (φPSI, φPSII, qP, qN, Y (ND)) are closely related to the dark reaction CO2 assimilation rate (A), which is similar to low-concentration CO2 and no light conditions, indicating that the Kelvin cycle passivation The signal-induced photosynthetic response plays an important role. However, the reduction of electron transfer on the PSI receptor side due to VP has no obvious correlation with the dark reaction CO2 assimilation rate (A), and does not depend on the influence of external CO2 concentration and light intensity. Therefore, it is speculated that there are two different ways to passivate the light reaction caused by VP in geranium, that is, it strongly depends on the dark reaction passivation and does not depend on the dark reaction passivation route.
This article follows the first article published by Japanese scholars on the simultaneous measurement of gas exchange-P700-chlorophyll fluorescence ) H dehydrogenase (NDH) complex performs a significant physiological role during photosynthesis and plant growth at low temperature in rice. The Plant Journal, 2011: in press. -Articles on chlorophyll fluorescence.
Figure 1 Geranium stimulated parts, potential measurement parts and fluorescence parameter measurement parts.
E1 and E2 are the first and second electrodes respectively, ER is the reference electrode, the distance between E1 and E2 is about 8cm, and the plants are stimulated by burning the tip of the leaf (3cm2 area, 3-4s).
Fig. 2 Potential, CO2 assimilation rate (A), stomatal conductance (GH2O), PSI and PSII quantum yield (φPSI, φPSII) changes
a Electrical signal propagates to the blade (n = 8); b Electrical signal does not propagate to the blade (n = 2).
Figure 3 Under different conditions, VP-induced CO2 assimilation rate (A), stomatal conductance (GH2O), and photoreaction stage parameters (φPSI, φND, φNA, φPSII, qN, qP) change.
a under control conditions (light intensity 100 μmol m-2s-1, external CO2 concentration 360 μl l-1); b without light conditions; c low CO2 concentration (15 μl l-1), Ci is intercellular CO2 concentration
Figure 4 CO2 assimilation rate (A) changes.
a stomatal conductance; b light response parameters; cVP and low concentration CO2 induction.
Figure 5 The relationship between the CO2 assimilation rate (A) and the parameters of the photoreaction stage under VC conditions.
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