Main conclusion
Higher vacuolar proton pump activity may increase plant energy and nutrient use efficiency and provide the
nexus
between plant inoculation with
Herbaspirillum seropedicae
and growth ...promotion.
Global change and growing human population are exhausting arable land and resources, including water and fertilizers. We present inoculation with the endophytic plant-growth promoting bacterium (PGPB)
Herbaspirillum seropedicae
as a strategy for promoting growth, nutrient uptake and photosynthetic efficiency in rice (
Oryza sativa
L.). Because plant nutrient acquisition is coordinated with photosynthesis and the plant carbon status, we hypothesize that inoculation with
H. seropedicae
will stimulate proton (H
+
) pumps, increasing plant growth nutrient uptake and photosynthetic efficiency at low nutrient levels. Plants were inoculated and grown in pots with sterile soil for 90 days.
Herbaspirillum seropedicae
endophytic colonization was successful and, as hypothesized, inoculation (1) stimulated root vacuolar H
+
pumps (vacuolar H
+
-ATPase and vacuolar H
+
-PPase), and (2) increased plant growth, nutrient contents and photosynthetic efficiency. The results showed that inoculation with the endophytic bacterium
H. seropedicae
can promote plant growth, nutrient uptake and photosynthetic efficiency, which will likely result in a more efficient use of resources (nutrients and water) and higher production of nutrient-rich food at reduced economic and environmental costs.
This study aimed to evaluate in the papaya Tainung genotype, the effects of partial root-zone drying (PRD) technique on soil water regimes by using different frequencies of shifting irrigation-side ...of plant row and the effects of PRD technique on (1) crop agronomic performance, (2) titratable fruit acidity (TA), (3) total soluble solids (TSS), and TSS/TA ratio. Also, we analyze the spatial dynamic of papaya condition using normalized difference vegetation index (NDVI) from different satellite images. The study was conducted in the semi-arid region of Bahia (BA) and Minas Gerais (MG), Brazil. The combination of 100% (Full irrigation-FU), 50%, and 35% in the irrigation depth (WID) and frequencies of shifting plant-row side irrigation of 0 (Fixed Irrigation-FX), 7, 14, and 21 days were applied. Nine treatments were studied in BA and five in MG. The water available in the soil was reduced to 44% for frequencies of shifting plant-row side irrigation of 7 days, 50% for 14 days, and 85% for 21 days, compared to the soil water availability at field capacity. Partial water deficit in the soil through the PRD technique did not significantly reduce the total root length, effective root depth, and root effective horizontal distance of the papaya Tainung genotype. However, PRD treatments showed leaf abscission, which resulted in reduced leaf area and NDVI values, especially in the MG experiment. Papaya yield and fruit quality were not affected. However, except for PRD 21 35%, irrigation water depth reduced to 50 and 35% under PRD increased crop water productivity (CWP) in papaya plants. Thus, the PRD technique may save 35% of WID using the alternation of lateral shift irrigation of crop row every 7 days under water scarcity in semi-arid regions. The NDVI index was important to compare the papaya canopy vigor between the experimental areas studied. We also confirmed the potential of NDVI to monitor the vigor of papaya canopy, since we could notice the sensibility of NDVI to identify water stress in papaya in higher vapor pressure deficit (VPD) conditions occurred in October 2016 and January 2017 in Bom Jesus da Lapa-BA. Therefore, the PRD strategy can be a useful tool to save water in papaya cultivation under semi-arid conditions.
Ecophysiology of iron homeostasis in plants Krohling, Cesar Abel; Eutrópio, Frederico Jacob; Bertolazi, Amanda Azevedo ...
Soil science and plant nutrition,
01/2016, Letnik:
62, Številka:
1
Journal Article
Recenzirano
Odprti dostop
In nature, iron (Fe) occurs in abundance and ranks fourth among all elements on Earth’s surface. Still, its availability to plants is reduced, once this element is in the form of hydrated oxides, ...which can limit plant productivity and biomass production. On the other hand, in high concentrations, this essential micronutrient for the plants can become a toxic agent, increasing the environmental contamination. Fe is necessary for the maintenance of essential processes like respiration and photosynthesis, participating in the electron transport chain and in the conversion between Fe ²⁺ and Fe ³⁺, being a key element for carbon dioxide (CO ₂) fixation and, therefore, important for crop production of cultivated or natural species. The balance of Fe should be strictly controlled, because both its deficiency and its toxicity affect the physiological process of plants. In aerated soils Fe is present in the form of Fe ³⁺, which is the oxidized form and is less available to plants, so these organisms have developed different strategies for absorption, transport and storage of Fe. Deficiency and excess of Fe correlate with local soil conditions and with the care adopted in plant nutrition during the phenological phases and/or in the course of its cultivation. In situations of excessive accumulation of Fe in tissues, an enhancement of hydroxyl radical generation (OH •) occurs by Fenton reaction. Here, we review the nutritional, genetic and ecophysiological aspects of uptake, translocation and accumulation of Fe ions in plants growing under conditions of deficiency or toxicity of this metal.
Climate changes boosted the frequency and severity of drought and heat events, with aggravated when these stresses occur simultaneously, turning crucial to unveil the plant response mechanisms to ...such harsh conditions. Therefore, plant responses/resilience to single and combined exposure to severe water deficit (SWD) and heat were assessed in two cultivars of the main coffee-producing species:
cv. Icatu and
cv. Conilon Clone 153 (CL153). Well-watered plants (WW) were exposed to SWD under an adequate temperature of 25/20°C (day/night), and thereafter submitted to a gradual increase up to 42/30°C, and a 14-d recovery period (Rec14). Greater protective response was found to single SWD than to single 37/28°C and/or 42/30°C (except for HSP70) in both cultivars, but CL153-SWD plants showed the larger variations of leaf thermal imaging crop water stress index (CWSI, 85% rise at 37/28°C) and stomatal conductance index (I
, 66% decline at 25/20°C). Both cultivars revealed great resilience to SWD and/or 37/28°C, but a tolerance limit was surpassed at 42/30°C. Under stress combination, Icatu usually displayed lower impacts on membrane permeability, and PSII function, likely associated with various responses, usually mostly driven by drought (but often kept or even strengthened under SWD and 42/30°C). These included the photoprotective zeaxanthin and lutein, antioxidant enzymes (superoxide dismutase, Cu,Zn-SOD; ascorbate peroxidase, APX), HSP70, arabinose and mannitol (involving
sugar synthesis), contributing to constrain lipoperoxidation. Also, only Icatu showed a strong reinforcement of glutathione reductase activity under stress combination. In general, the activities of antioxidative enzymes declined at 42/30°C (except Cu,Zn-SOD in Icatu and CAT in CL153), but HSP70 and raffinose were maintained higher in Icatu, whereas mannitol and arabinose markedly increased in CL153. Overall, a great leaf plasticity was found, especially in Icatu that revealed greater responsiveness of coordinated protection under all experimental conditions, justifying low PI
and absence of lipoperoxidation increase at 42/30°C. Despite a clear recovery by Rec14, some aftereffects persisted especially in SWD plants (
., membranes), relevant in terms of repeated stress exposure and full plant recovery to stresses.
The chlorophyll meter (SPAD-502) is a simple, portable diagnostic tool that measures the greenness or relative content of leaves. Compared to the traditional destructive methods, the use of this ...equipment saves time, space and resources. The objective of this study was to establish a correlation between the photosynthetic pigments content extracted in DMSO, the total nitrogen content and the chlorophyll
a fluorescence variables with the SPAD-502 readings in
Coffea canephora Pierre leaves. The SPAD-502 has been shown to be a good tool to diagnose the integrity of the photosynthetic system in coffee leaves, and can thus help in the advanced interpretations of the photochemical process of these plants. The SPAD readings lower 40 show impairment in photosynthetic process. Thus, the portable chlorophyll SPAD-502 can be used to analyze the photosynthetic pigments, and total nitrogen can also help in interpretation of the photochemical process in coffee plants.
Increases in water use efficiency (WUE) and the reduction of negative impacts of high temperatures associated with high solar radiation are being achieved with the application of fine particle film ...of calcined and purified kaolin (KF) on the leaves and fruits of various plant species. KF was applied on young
and
plants before their transition from nursery to full sunlight during autumn and summer. The effects of KF were evaluated through the responses of leaf temperature (T
), net CO
assimilation rate (
), stomatal conductance (
), transpiration (
), WUE, crop water stress index (CWSI), index of relative stomatal conductance (I
), initial fluorescence (F
), and photosynthetic index (PI) in the first 2-3 weeks after the plant transitions to the full sun. All measurements were performed at midday. In
plants, KF decreased the T
up to 6.7°C/5.6°C and reduced the CWSI. The plants that were not protected with KF showed lower
,
,
, and I
than those protected with KF.
plants protected with KF achieved higher WUE compared with those not protected by 11.23% in autumn and 95.58% in summer. In both
sp., KF application reduced F
, indicating reduced physical dissociation of the PSII reaction centers from the light-harvesting system, which was supported with increased PI. The use of KF can be recommended as a management strategy in the transition of
seedlings from the nursery shade to the full sunlight, to protect leaves against the excessive solar radiation and high temperatures, especially in
during the summer.
Achieving food security in a context of environmental sustainability is one of the main challenges of the XXI century. Two competing strategies to achieve this goal are the use of genetically ...modified plants and the use of plant growth promoting microorganisms (PGPMs). However, few studies assess the response of genetically modified plants to PGPMs. The aim of this study was to compare the response of over-expressing the vacuolar H
-PPase (AVP) and wild-type rice types to the endophytic fungus;
.
plants (WT and AVP) were inoculated with
and 30 days later, morphological, ecophysiological and bioenergetic parameters, and nutrient content were assessed. AVP and WT plant heights were strongly influenced by inoculation with
, which also promoted increases in fresh and dry matter of shoot in both genotypes. This may be related with the stimulatory effect of
on ecophysiological parameters, especially photosynthetic rate, stomatal conductance, intrinsic water use efficiency and carboxylation efficiency. However, there were differences between the genotypes concerning the physiological mechanisms leading to biomass increment. In WT plants, inoculation with
stimulated all H
pumps. However, in inoculated AVP plants, H
-PPase was stimulated, but P- and V-ATPases were inhibited. Fungal inoculation enhanced nutrient uptake in both shoots and roots of WT and AVP plants, compared to uninoculated plants; but among inoculated genotypes, the nutrient uptake was lower in AVP than in WT plants. These results clearly demonstrate that the symbiosis between
and AVP plants did not benefit those plants, which may be related to the inefficient colonization of this fungus on the transgenic plants, demonstrating an incompatibility of this symbiosis, which needs to be further studied.
Considering the expansion of forest plantations over the Brazilian territory and the imminent increase in air temperatures due to global warming, the search for technologies that ensure high levels ...of productivity and high quality plants in clonal nurseries is essential. Applying kaolin-based particle films (KBPF) has been used as a physical barrier to reduce the negative effects of excessive solar radiation and adverse temperatures. The effects of KBPF on production and physiological quality of eucalyptus mini-cuttings were evaluated during two different seasons. A randomized block design was used, consisting of five treatments and four replications. Five concentrations (0, 3%, 5%, 7%, and 10%) were tested here and six weekly replicates of each concentration was applied. The different kaolin concentrations and seasonal variations resulted in a quadratic response of the leaf SPAD reading during both daily evaluation periods. KBPF applications resulted in a quadratic response of photochemical efficiency in the morning period, and an increasing specific leaf weight linear response, and during the dry season, the different kaolin concentrations resulted in a bud length quadratic response. The results indicated that the kaolin application maintained the production and yield index statistically equal between weekly KBPF applications, improving photochemical efficiency, leaf thickness, SPAD reading, and bud length. The use of KBPF could reduce the intervals between collections of mini-cuttings and increase nursery yields in environments that present high temperatures.
Climate change is expected to intensify water restriction to crops, impacting on the yield potential of crops such as popcorn. This work aimed to evaluate the performance of 10 field cultivated ...popcorn inbred lines during two growing seasons, under well-watered (WW) and water stressed (WS) (ψ
soil
≥ −1.5 MPa) conditions. Water stress was applied by withholding irrigation in the phenological phase of male pre-anthesis. Additionally, two contrasting inbred lines, P7 (superior line) and L75 (low performer) were compared for grain yield (GY) and expanded popcorn volume (EPV), selected from previous studies, were tested under greenhouse conditions. In the field, no genotype x water condition x crop season (G×WC×CS) interaction was observed, whereas GY (−51%), EPV (−55%) and leaf greenness (SPAD index) measured 17 days after anthesis (DAA) (> −10%) were highly affected by water limitation. In general, root traits (angles, number, and density) presented G×WC×CS interaction, which did not support their use as selection parameters. In relation to leaf senescence, for both WS and WW conditions, the superior inbred lines maintained a stay-green condition (higher SPAD index) until physiological maturity, but maximum SPAD index values were observed later in WW (48.7 by 14 DAA) than in WS (43.9 by 7 DAA). Under both water conditions, negative associations were observed between SPAD index values 15 and 8 days before anthesis DBA), and GY and EPV (r ≥ −0.69), as well as between SPAD index 7, 17, and 22 DAA, and angles of brace root (AB), number of crown roots (NC) and crown root density (CD), in WS (r ≥ −0.69), and AB and CD, in WW (r ≥ −0.70). Lower NC and CD values may allow further root deepening in WS conditions. Under WS P7 maintained higher net photosynthesis values, stomatal conductance, and transpiration, than L75. Additionally, L75 exhibited a lower (i.e., more negative) carbon isotope composition value than P7 under WS, confirming a lower stomatal aperture in L75. In summary, besides leaf greenness, traits related to leaf photosynthetic status, and stomatal conductance were shown to be good indicators of the agronomic performance of popcorn under water constraint.
The main characteristic of Cannabis sativa L. is the production of compounds of medicinal interest known as phytocannabinoids. Environmental factors and crop management practices are directly related ...to the yield of these compounds. Knowing how these factors influence the production of phytocannabinoids is essential to promote greater metabolite yield and stability. In this review, we aim to examine current cannabis agronomic research topics to identify the available information and the main gaps that need to be filled in future research. This paper introduces the importance of C. sativa L., approaching state-of-the-art research and evaluating the influence of crop management and environment conditions on yield and phytocannabinoid production, including (i) pruning; (ii) light and plant density; (iii) ontogeny; (iv) temperature, altitude, and CO2 concentration; (v) fertilization and substrate; and (vi) water availability, and presents concluding remarks to shed light on future directions.