Pepper Shoots Research Articles

Biochar and silicon relegate the adversities of beryllium stress in pepper by modulating methylglyoxal detoxification and antioxidant defense mechanism.

Industrial activities have escalated beryllium (Be) release in environment which negatively affect plant growth and human health. This investigation describes Be-induced stress in pepper and its palliation by application of pineapple fruit peel biochar (BC) and potassium silicate (Si). The treatment of Be reduced seedling length, biomass, and physiological attributes and enhanced electrolyte leakage, hydrogen peroxide (H2O2), superoxide (O2•-) level in pepper plants; however, these oxidative stress markers were reduced with combined treatment (Be + BC + Si). Application of BC and Si also lowered Be cumulation in roots and shoots of pepper. Under combined treatment, superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) activities exhibited significant enhancement 19, 7.6, 22.8, and 48%, respectively, in Be-stressed pepper. The Be + BC + Si increased peroxidase (POD), glutathione S-transferase (GPX), and glutathione peroxidase (GST) activities 121, 55, and 53%, respectively, as compared to Be-treated pepper. Methylglyoxal level was reduced in pepper with rise in glyoxalase I and II enzymes. Thus, combined application of SS and BC effectively protects pepper against oxidative stress induced by Be by increasing both antioxidant defense and glyoxalase systems. Hence, pineapple fruit peel biochar along with potassium silicate can be used for enhancing crop productivity under Be-contaminated soil.

Ball-milled sepiolite/phosphate rock for simultaneous remediation of cadmium-contaminated farmland and alleviation of phosphorus deficiency symptoms in pepper

Herein, ball-milled combination of sepiolite and phosphate rock was carried out for synergistic passivation of Cd in soil and alleviation of phosphorus deficiency in pepper. The as-prepared BM-Sep2PR1 exhibited extensive pH adaptability and fast uptake for Cd(II) with maximal uptake capacity of 78.67 mg/g. After application of 0.5 % BM-Sep2PR1, the bioavailability of Cd in soil decreased by 58.2 %, and its unstable forms declined by 57.0 % with transformation into residual speciation such as Cd3(PO4)2 and CdnCa5-n(PO4)3OH. Moreover, BM-Sep2PR1 significantly decreased the amount of Cd in pepper shoot (77.8 %) and root (54.8 %), and the bioconcentration factors (soil-root) and translocation factors (root-shoot) were significantly reduced by 54.8 % and 50.8 %, respectively. Notably, the soil available phosphorus, pepper root vitality, and photosynthetic pigment content increased by 202.8 %, 136.4 %, and 58.4 %, respectively, thus significantly alleviating the phosphorus deficiency symptoms of pepper. Additionally, BM-Sep2PR1 improved soil microbial community structure, especially enhanced the abundance of microorganism involved in nutrient cycling and heavy metal resistance. The Cd passivation mechanisms of BM-Sep2PR1 were identified as pore filling, electrostatic attraction, ion exchange, surface complexation, and chemical precipitation. Overall, this study provided a potential strategy for synergetic soil remediation and plant nutrient supplement by using ball-milled functional materials.

A New Approach: Ethyl Formate Fumigation to Control Bemisia tabaci (Hemiptera: Aleyrodidae) in a Yellow Melon Vinyl House

Due to concerns over the resistance development to existing pesticides, chemical poisoning among farmers, and chemical residue on crops, sprung up a growing need to develop new pest control strategies for utilization in protected houses in Korea. A series of experiments tested a new technology using a fumigant, ethyl formate, in growing crops in the protected houses. It was revealed that the glasshouse was inadequate for the fumigation system using the fumigant since ethyl formate gas sharply decreased due to gas leaking through the gaps between the glass frames. On the other hand, the gas concentration was stable during the fumigation process. Experiments were also conducted to evaluate its phytotoxicity on cucurbits crops (yellow melon). The crops were fumigated at 20 °C in three fumigation schedules (2, 4, and 12 h). The results revealed that the developmental stages of yellow melon showed no sign of phytotoxicity in all conditions. However, the fumigation damaged the shoots of red pepper in higher humidity and at a longer duration. Interestingly, Bemisia tabaci were (100%) completely killed in all these conditions. Based on the results of the above experiments on the high efficacy on the control of Bemisia tabaci and zero phytotoxic effects of the ethyl formate fumigation on yellow melon, verification experiments for the effectiveness were conducted thrice in farmer’s yellow melon vinyl houses and once in a farmer’s cucumber vinyl house. Results demonstrated that ethyl formate fumigation for 2 h at 2 g m−3 concentration could 100% kill the adults of Bemisia tabaci with no phytotoxic effect on the crops. Therefore, we could conclude that the 2-h fumigation system with 2 g m−3 ethyl formate would be a new alternative to the existing chemical spraying methods.

Growth of Pepper Plant (Piper nigrum Linn.) After Application of Organic Fertilizer Leaves of Gamal (Gliricidia sepium (Jacq) Kunth.)

Pepper (Piper nigrum Linn.) is the most traded spice commodity among other spices. The problem with pepper farming in West Kalimantan is the lack of nutrient availability because plantation land is dominated by ultisol soils. Gamal leaf liquid organic diapers application is expected to increase the availability of nutrients in the growing media. The aim of the study was to determine the nutrient content of the liquid organic diapers of gamal leaves, to see the effect, as well as the best concentration and time of application on the vegetative growth of pepper plants. The study was carried out for four months, namely from January to April 2020 at the Pepper Plantation of Tengon Village, using a factorial compeletely randomized design pattern consisting of 2 factors, the concentration such as 10%, 20%, 30%, 40% control and liquid organic fertilizer application time (every time week and every two weeks). The results showed that liquid organic fertilizer of gamal leaves contained 12.7% C-organic., 0.27% N-Total., 47.03 C/N ratio., 0,25% P., and 0,29 K. The results of the research that giving Gamal leaf liquid organic fertilizer had a significant effect on shoot length, number of shoots and number of leaves of pepper plants, however, it did not significantly affect the time of emergence of pepper shoots. Liquid organic fertilizer concentration of 40% and time of application every week gave the best effect on shoot length (25.33 cm), number of shoots (4.33 shoots), and number of leaves (14.33 strands).  It was concluded that the  liquid organic diapers concentration treatment of gamal leaves had a significant effect on shoot length, number of shoots, and number of leaves of pepper plants but did not significantly affect the time of shoots emerging for pepper plants.  The best poc concentration that increases pepper plant growth is 40% with every week application.  It is recommended that further research can be carried out on the manufacture of  liquid organic diapers of gamal leaves combined with animal waste on the growth of pepper plants, with application time of 2-3 times in one week.

Effect of Planting Density on the Yield and Growth of Intercropped Tomatoes and Peppers in Florida

Florida vegetable growers are facing high production costs due to high input costs, lower profitability, and competition from foreign markets. Multi/intercropping allows growers to increase the yields and profits per unit area by producing multiple crops on the same beds. Experiments determining the effects of intercropping and plant spacing was conducted in Fall 2018 and 2019 at Gulf Coast Research and Education Center, Balm. Tomato and bell pepper were intercropped at low and high planting density on plastic-covered beds. Bell pepper shoot biomass was significantly (P < 0.001) reduced when intercropped with tomato, compared with monocropped bell pepper. However, tomato shoot biomass was significantly reduced when tomato plant density increased, but it was unaffected by bell pepper intercropping. Biomass of both crops was unaffected by relay cropping. Bell pepper yields when intercropped with tomato at low density (60 cm tomato-tomato and 38 cm pepper-pepper) had similar yields to bell pepper planted alone in low and high planting density. We concluded that bell pepper plants were more sensitive to interspecific competition, whereas tomato plants were more sensitive to intraspecific competition. Intercropping may be a viable option for growers at recommended plant densities used for monocrops. However, high plant density is not recommended.

Evaluation on the performance of red pepper (Capsicum annuum) and tomato (Lycopersicon esculentum) under various fermented liquid fertilizers

Farm-made liquid fertilizers are used in organic agriculture, however crop growth promotion and mineral nutrion levels in liquid fertilizers can vary drastically depending on manufacturing methods. Therefore, laboratory research was conducted during 2018 at Sunchon National University, Korea to determine certain manufacturing methods to produce the best fermented liquid fertilizers for red pepper and tomato seedlings. All extracts had acidic pH levels except for fish II and bone + fish meal I extracts. During storage, bone + fish I-V and tomato I-IV experienced almost no change in pH whereas all other extracts experienced a reduction in pH. Although extraction EC values varied during storage, most EC values were not high and could therefore be used for extracts. Overall, extracts used in this study were far more effective growth promotors of red pepper plants than tomato plants and shoot fresh weight with increase at a greater rate than plant height in response to fertilizers. Most extracts produced using onion, fish, and bone + fish meal had red pepper shoot fresh weight growth promotion levels of 59 to 128%. The most effective growth promoting extracts were onion extracts IV and V which produced 182 and 202% higher shoot fresh weight of red pepper, respectively. In all extracts, there was greater variation in micro-element than macro-elemnet levels. Macro and micro-element levels were higher in fish and sesame oil cake extracts than in onion, tomato, red pepper leaf, and bone + fish extracts. Generally, macro-elements such N, P, K, Ca, Mg, and Na in fish extracts were higher than in bone + fish, tomato, onion, red pepper leaf, and sesame oil cake extracts. Micro-elements such as Zn, Fe, Mn, and Mo in fish extracts were also higher than in bone + fish, tomato, onion, red pepper leaf, and sesame oil cake extracts. Despite having greater levels of either micro or macro-nutrients, some extracts had far lower levels of growth promotion. Crop growth promotion in extracts varied depending on materials, material combination, and material amounts. Thus, farm-made liquid fertilizers, though effective, need to use a standardized manufacturing method in order to produce the most effective and consistant growth promoting liquid fertilizers.

The better suppression of pepper Phytophthora blight by arbuscular mycorrhizal (AM) fungus than Purpureocillium lilacinum alone or combined with AM fungus

Phytophthora blight caused by Phytophthora capsici (Pc) is one of the most economically destructive soilborne diseases of pepper (Capsicum annum L.) on a global scale. Biocontrol using antagonistic microbes, such as Purpureocillium lilacinum (Pl) and arbuscular mycorrhizal (AM) fungus Funneliformis caledonium (Fc), is one of the significant strategies for ecologically sound plant disease management. The purpose of this work was to investigate the sole and combined suppression of pepper Phytophthora blight by Fc and Pl. The 14-week pot experiment with three pepper plants per pot included five treatments: control (non-inoculation), inoculation with Pc, inoculation with Pc and Pl (Pc + Pl), inoculation with Pc and Fc (Pc + Fc), and inoculation with Pc, Pl, and Fc (Pc + Pl + Fc). Pots were randomly arranged with eight replicates per treatment. The incidence and severity of Phytophthora blight at plant full productive stage were recorded. The biomasses and N, P, and K concentrations of pepper shoots, roots, and fruits were all measured. In addition, root mycorrhizal colonization rate and soil pH, phosphatase activity, and available P concentration were also tested. The inoculation of Pc induced both high incidence (92%) and severity (33%) of pepper Phytophthora blight, and the alleviating effects of Pl, Fc, and Pl + Fc were 46%, 79%, and 59%, respectively. The Fc significantly increased (P < 0.05) root mycorrhizal colonization, nutrient (N, P, and K) acquisition, plant biomass, and fruit yield of pepper, while Pl only significantly increased (P < 0.05) plant nutrient (N and P) acquisition and tended to increase the fruit yield. The Pc, Pl, and Fc all had additive effects on decreasing soil pH, but only Fc significantly increased (P < 0.05) soil phosphatase activity and available P concentration, contributing partly to the elevated P acquisition as well as the increased P concentrations in both shoot and root. Compared with the sole inoculation of Fc, the extra inoculation of Pl had negative effects on mycorrhizal colonization, soil P mobilization, and plant growth and nutrient acquisition. It suggests that AM fungus (Fc) has the superiority of formatting symbioses with plant roots and enhancing soil P mobilization for the suppression of pepper Phytophthora blight compared with Pl, and the joint application of different fungal agents to improve plant health needs careful consideration.

Response of irradiated chilli pepper shoots (Capsicum annuum. L.) propagated in vitro to drought stress tolerance

Drought stress in plants caused by water deficiency. In Vitro selection with mutation techniques offered stress tolerance in plants. Shoot tips of chilli pepper (Capsicum annuum . L.) exposed for gamma radiations at the doses (0, 10 and 20 Gy). Irradiated shoots were exposed to stress tolerance in the presence of Polyethylene Glycol (PEG 6000) in MS medium. Analysis of variance results for all characters studied were found to be significant, highest dose 20 Gy interaction with 40 g.l-1 of PEG gave highest number 6.2 shoot. explant-1 whereas 10 Gy and 40 g.l-1 of PEG gave highest plant height 6.04 cm. Further, higher accumulation of proline reached 26.97 mg. g-1 at interaction of 20 Gy+ 60 g.l-1 PEG while highest accumulation of CHO found at 20 Gy+ 40 g.l-1 PEG.

Effects of biochar amendment on relieving cadmium stress and reducing cadmium accumulation in pepper.

Biochar is widely used in agricultural soils or heavy metal-polluted soils to improve the quality of the soils, which would affect the growth of the plant. However, the information of biochars' effect on the plant growth was still lacking, especially for the physiological response of the plant. Pot experiments were used to examine the effect of willow-derived biochars at two temperatures (450 and 600°C) on cadmium (Cd) accumulation in pepper and to reveal the response of physiological parameters to exogenous Cd stress (1 and 5mg/kg). The results showed that the accumulation of Cd in pepper roots was higher than that in pepper shoots. For low level of Cd treatments, high additional rates of the biochars could obviously reduce the accumulation of Cd in the pepper roots. Moreover, there was a negative correlation between the C content of the biochar-amended soils and the Cd content of the pepper root, suggesting that the application of biochar to the soil decreased the Cd accumulation in the root. A positive relationship between the H/C ratios of biochar-amended soils and their corresponding Cd concentrations in pepper root indicated that low thermal temperature-derived biochar could play an important role in immobilizing Cd in the soil. Furthermore, on the condition of low Cd level of treatments, the malondialdehyde content decreased in biochar-amended soils, especially at high biochar application rate. The chlorophyll content increased with increasing the rates of the biochar application. The physiological parameters indirectly proved that the application of biochar did not always alleviate the toxic effects of Cd on pepper leaves at high Cd concentration.

RESPONSE OF CERTAIN PHYTOCHEMICAL CONSTITUENTS IN SWEET PEPPER LEAVES TO SOME BIO-STIMULANTS UNDER TWO TYPES OF SALINITY

High salinity level of NaCl and CaCl2 (4000 mg/L) markedly increased whereas the low levels and its combination decreased electrolyte leakage percentage (E.L. %) in sweet pepper leaves as compared to the unstressed plants. In addition, application of all selected bio-regulators used at both applied levels, in most cases, alleviated the harmful effect of salinity on E.L. % especially ascorbic acid at 50 mg/L.&#x0D; Relative water content (RWC) and photosynthetic pigments were significantly increased thereafter decreased as salinity levels increased. In addition, CaCl2 at low level caused a great increase in RWC % followed by NaCl+CaCl2 and NaCl (2000 mg/L). While, pre-soaking seeds in both levels of the applied bio-stimulants caused a significant increase in RWC % and the photosynthetic pigments concentrations . In addition, AsA at 50 mg/L or SA at 75 mg/L was more effective in this respect as compared to the untreated plants.&#x0D; Ascorbic acid, proline, total phenols as well as total soluble carbohydrates concentrations in sweet pepper shoot were increased with increasing salinity levels from 2000 to 4000 mg/L of all salinity types. In addition, NaCl led to a great increase followed by NaCl+CaCl2 and CaCl2 as compared to the unstressed plants. In addition, pre-soaking seeds in SA, AsA, tocopherol and yeast extract at both levels increased ascorbic acid, proline, total phenols as well as total soluble carbohydrates concentrations under saline conditions. Moreover, AsA at 50 mg/L or SA at 75 mg/L was more effective in this respect as compared with the other treatments

Allelopathic interaction of pepper (Capsicum annuum) and pearl millet (Pennisetum glaucum) intercropped

Intercropping is common practice in many regions of Tunisia, particularly in Cap-Bon where different crops such as tomato, pepper, cucumber, peanut, corn, pearl millet and sorghum are grown together in the same field and at the same time for self-sufficiency. A number of these crops and vegetables are known for their allelopathic activities. The interaction between plants could be within the individuals of the same species (intraspecific interaction or autotoxicity) or between different species (interspecific interaction or teletotoxicity). Little is known about allelopathic interaction of some of these intercropped plants in mixed farming systems in our local conditions. Therefore, the objectives of the present investigation are to evaluate, under laboratory condition, the allelopathic effect of mixed crops, which interacted positively or negatively when cultivated together in the same field. Two plant species were used to study the effects of their aqueous extract on germination and growth of each other (pepper and pearl millet). The results suggested that aqueous extracts from shoots and roots significantly inhibited germination and seedling growth and the inhibitory effects were increased proportionally with the extract concentration. The shoot and root aqueous extract also exhibited intraspecific and interspecific allelopathy. Generally, it was observed that roots were more toxic than shoots. For root extract, the highest inhibition percentage was gained from the effect of pearl millet on pepper (40%) and highest autotoxicity was observed from pearl millet (36%). The effect of shoot extract on germination indicated that the highest reduction (55%) was obtained from pepper shoot extract on pearl millet and highest autotoxicity was observed from pepper which reached (45%). In most cases autotoxicity appeared to be more severe than teletotoxicity, on seed germination of the two intercropped plant species. DOI: http://dx.doi.org/10.3126/ije.v3i1.9940 International Journal of Environment Vol.3(1) 2014: 32-40

Does Inoculation with Glomus mosseae Improve Salt Tolerance in Pepper Plants?

A pot experiment was conducted to determine the effects of Glomus mosseae inoculation on growth and some biochemical activities in roots and shoots of pepper (Capsicum annuum L. cv. Zhongjiao 105) plants subjected to four levels of NaCl [0 (control), 25 (low), 50 (medium), and 100 (high) mM] for 30 days, after 30 days of establishment under non-saline conditions. In mycorrhizal (M) plants, root colonization varied from 48 to 16 %. M plants had higher root and shoot dry weight and leaf area compared with non-mycorrhizal (NM) plants. Under salinity stress, M plants accumulated higher amounts of leaf photosynthetic pigments as well as soluble sugar, soluble protein, and total free amino acids in roots and shoots than those of NM plants. In contrast, the accumulation of proline was less intense in M plants than NM plants. Salt stress induced oxidative stress by increasing malondialdehyde (MDA) content; however, the extent of oxidative damage in M plants was less compared with NM plants due to G. mosseae-enhanced activity of superoxide dismutase (SOD) and peroxidase (POD). We concluded that inoculation with G. mosseae improved growth performance and enhanced salt tolerance of pepper plants via improving photosynthetic pigments and the accumulation of organic solutes (except proline), reducing oxidative stress, and enhancing antioxidant activities of the SOD-POD system.

ELEMENTAL COMPOSITION OF PEPPER PLANTS FERTILIZED WITH PELLETIZED POULTRY MANURE

Poultry manure (PM) has been traditionally applied to crops for decades as an organic fertilizer, because it is a good and balanced source of plant nutrients. Its effect on plant growth and yield has been widely investigated and is well known. However, there has been little effort to relate elemental compositions of the manure applied to their concentrations in the plants. The objective of this study was to examine the effects of PM on the growth, and essential and non-essential element composition of pepper (Capsicum annuum) leaves and also fruits. Pepper plants were grown in soil with 0, 10, 20, and 40 g kg−1 PM under greenhouse conditions. Concentrations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), silicon (Si), aluminum (Al), iron (Fe), zinc (Zn), copper (Cu), manganese (Mn), molybdenum (Mo), chloride (Cl), nickel (Ni), bromine (Br), rubidium (Rb), strontium (Sr), barium (Ba), lanthanum (La), and cerium (Ce) in leaves at the flowering stage and in fruits were determined by polarized energy dispersive X-ray fluorescence (PEDXRF). Poultry manure fertilization significantly improved pepper shoot growth and also fruit yield, and increased leaf and fruit P concentrations but not N, K, Mg, Si, Al, Ni, and Fe. Leaf Ca was significantly reduced by increased rate of PM application. Applied PM increased the concentrations of leaf and fruit Zn and Cl. Poultry manure applications had a positive effect on the concentrations of leaf Cu, and fruit Mn. The concentrations of Rb and Ce in fruits and Br in fruit and leaves were increased by PM treatments. Applied PM levels had no clear effect on the concentrations of Ba and La in pepper leaves. The leaf Ba was the highest with 10 g kg−1 PM, and leaf La was higher in 20 and 40 g kg−1 PM treatments than in the control.

Role of Endomycorrhizae on Controlling Stem- and Root-Rot of Pepper Caused by Sclerotium rolfsii

This study was designed to investigate the effect of inoculation time with vesicular arbuscular mycorrhizal (VAM) fungi, Glomus spp., on the interaction between root-rot and stem-rot of pepper caused by Sclerotium rolfsii Sacc. as well as its growth. The results indicated that addition of Glomus spp. significantly increased the shoot and root fresh and dry weight with significant decrease to the disease severity (59-89%). Effect of the mycorrhizal inoculation using five species of Glomus by two different inoculation treatments on incidence of Sclerotium stem-rot as well as crop parameters of pepper plants inoculated with the tested fungus was investigated. Generally, mycorrhizal inoculation increased pepper shoot and root fresh and dry weight compared with uninoculated plants. Meanwhile, seedlings arose from seeds treated with Glomus spp. increased growth parameters and yield. G. coronatum and G. luteum were the best mycorrhizae to increase crop parameters. On the other hand, G. etunicatum, G. diaphanum and G. luteum were the best to protect pepper plants against S. rolfsii.

Nitrogen‐fixing bacteria with multiple plant growth‐promoting activities enhance growth of tomato and red pepper

As a suitable alternative to chemical fertilizers, the application of plant growth-promoting rhizobacteria has been increasing in recent years due to their potential to be used as biofertilizers. In the present work, 13 nitrogen-fixing bacterial strains belonging to 11 different genera were tested for their PGP attributes. All of the strains were positive for 1-aminocyclopropane-1-carboxylate deaminase (ACCD), indole-3-acetic acid (IAA), salicylic acid, and ammonia production while negative for cellulase, pectinase, and hydrocyanic acid production. The strains Pseudomonas sp. RFNB3 and Serratia sp. RFNB14 were the most effective in solubilizing both tri-calcium phosphate and zinc oxide. In addition, all strains except Pseudomonas sp. RFNB3 were able to oxidize sulfur, and six strains were positive for siderophore synthesis. Each strain tested in this study possesses at least four PGP properties in addition to nitrogen fixation. Nine strains were selected based on their multiple PGP potential, particularly ACCD and IAA production, and evaluated for their effects on early growth of tomato and red pepper under gnotobiotic conditions. Bacterial inoculation considerably influenced root and shoot length, seedling vigor, and dry biomass of the two crop plants. Three strains that demonstrated substantial effects on plant performance were further selected for greenhouse trials with red pepper, and among them Pseudomonas sp. RFNB3 resulted in significantly higher plant height (26%) and dry biomass (28%) compared to control. The highest rate of nitrogen fixation, as determined by acetylene reduction assay, occurred in Novosphingobium sp. RFNB21 inoculated red pepper root (49.6 nM of ethylene/h/g of dry root) and rhizosphere soil (41.3 nM of ethylene/h/g of dry soil). Inoculation with nitrogen-fixing bacteria significantly increased chlorophyll content, and the uptake of different macro- and micro-nutrient contents enhancing also in red pepper shoots, in comparison with uninoculated controls. The population estimation studies showed that nitrogen-fixing as well as total heterotrophic bacteria were also noticeably increased in soil and plant samples. The findings of this study suggest that certain nitrogen-fixing strains possessing multiple PGP traits could be applied in the development of biofertilizers.

CaHAM is autoregulated and regulates CaSTM expression and is required for shoot apical meristem organization in pepper

The angiosperm shoot apical meristem (SAM) is characterized by tightly organized cell layers and zones. The SAM's organization allows it to maintain its indeterminate nature while producing determinate lateral organs. Alterations in SAM gene expression partly account for the immense diversity in plant architecture. The GRAS protein family gene HAIRY MERISTEM (HAM) is an important regulator of SAM organization in Petunia and Arabidopsis. Here we describe CaHAM loss-of-function pepper mutants characterized by an arrested SAM following the formation of several leaves on the primary stem, complete inhibition of axillary meristem development, an expanded tunica domain and trichome formation on the SAM epidermis. CaHAM is expressed in the periphery of the SAM and in the vasculature of young leaves throughout plant development, reaching its highest level in the reproductive growth stage. Analysis of the effect of CaHAM loss-of-function on its own expression showed that CaHAM is negatively autoregulated. Furthermore, CaHAM negatively regulates the expression level and pattern of pepper SHOOT MERISTEMLESS (CaSTM), which is required to maintain the SAM in an undifferentiated state. We conclude that CaHAM is regulated to achieve adjusted functional levels and has a conserved role in controlling SAM maintenance, organization and axillary meristem formation.

Stenotrophomonas rhizophila DSM14405T promotes plant growth probably by altering fungal communities in the rhizosphere

Stenotrophomonas rhizophila DSM14405T is of high biotechnological interest as plant growth stimulator, especially for salinated conditions. The objective of this study was to determine the effect of plant species (cotton, tomato, and sweet pepper) on colonisation and plant growth promotion of this beneficial bacterium in gnotobiotic systems and in non-sterile soil. All plant structures (leaves, stems, and roots) were densely colonised by DSM14405T reaching up to 109 cells g−1 fresh weight; under gnotobiotic conditions the abundances were 4–5 orders of magnitude higher than in non-sterile soil. Under non-sterile conditions and ambient humidity, tomato shoots were more densely colonised than shoots of sweet pepper and cotton. S. rhizophila DSM14405T was shown to grow endophytically and colonise the vicinity of root hairs of tomato. Plant growth promotion was particularly apparent in tomato. In general, the impact of plant species on colonisation and plant growth promotion was more pronounced in soil than under gnotobiotic conditions and likely due to the control of diseases and deleterious microorganisms. S. rhizophila DSM14405T was shown to control diseases in sweet pepper and in cotton. Molecular profiling via single strand conformation polymorphism of internal transcribed spacers and 16S rRNA genes (PCR-single strand conformational polymorphism (SSCP)) revealed that S. rhizophila DSM14405T strongly affected fungal, but not bacterial communities in the rhizosphere of tomato and sweet pepper. Major SSCP bands related to uncultured fungi and Candida subhashii, disappeared in tomato rhizosphere after Stenotrophomonas treatment. This suggests an indirect, species-specific plant growth promotion effect of S. rhizophila via the elimination of deleterious rhizosphere organisms.

Changes in structure of red pepper (Capsicum annuum L.) seedlings shoots under aluminum stress conditions

The seedlings of the red pepper (&lt;i&gt;Capsicum annuum&lt;/i&gt; L.) cv. Trapez grown in water culture for a period of 14 days with Al (0, 10, 20 and 40 mg·dm&lt;sup&gt;-3&lt;/sup&gt; AlCl&lt;sub&gt;3&lt;/sub&gt;·6 H&lt;sub&gt;2&lt;/sub&gt;O). Some morphological and anatomical features of red pepper shoots were analyzed. Reduction in height and diameter of stems as well as decrease in fresh mass of shoots were observed after Al-treatment. In the hypocotyl the thickness of cortex parenchyma layer and the size of their cells were reduced. The aluminum treatment resulted in the increased in thickness of the epidermis outer cell wall. Under Al stress in the cotrex and the central cylinder parenchyma cells were present numerous enlarge plastids which contained large grains of starch and dark little bodies which were possible aluminum deposits. They weren`t observed in control seedlings.

Improvement of In Vitro Proliferation and Elongation of Habanero Pepper Shoots (Capsicum chinense Jacq.) by Temporary Immersion

This article describes the performance of nodal segments from Habanero pepper (Capsicum. chinense) during shoot induction and elongation under different semisolid and liquid culture conditions with various degrees of ventilation in which they were exposed to different levels of immersion and growth regulators. The ethylene content in non-ventilated containers, the age of the explant donor plants as well as the effect of thidiazuron and paclobutrazol on shoot induction and of gibberellic acid and AgNO3 on shoot elongation were also evaluated. A temporary immersion bioreactor (BioMINT™) was used for the multiplication and elongation of isolated shoots with very good results. We report an efficient protocol for the in vitro propagation of Habanero pepper that produces plants with a high survival rate when transplanted to soil.

The influence of arbuscular mycorrhizal colonisation on key growth parameters and fruit yield of pepper plants grown at high salinity

This study investigated the effects of arbuscular mycorrhizal (AM) colonisation by Glomus clarum on growth and fruit yield of pepper ( Capsicum annum cv. 11B 14) grown at high salinity. The experiment was conducted in pots containing a mixture of perlite and sand (1:1, v/v) under glasshouse conditions. Treatments were: (1) no added NaCl without arbuscular mycorrhizae (NS-AM), (2) no added NaCl with arbuscular mycorrhizae (NS + AM), (3) added 50 mM NaCl without arbuscular mycorrhizae (S1-AM) and (4) added 100 mM NaCl without arbuscular mycorrhizae (S2-AM), (5) added 50 mM NaCl with arbuscular mycorrhizae (S1 + AM) and (4) added 100 mM NaCl with arbuscular mycorrhizae (S2 + AM). The NaCl treatments reduced pepper shoot and root dry matter, and fruit yield compared with the non-saline treatments. The concentrations of N, P and K, in the leaves were significantly reduced by salinity stress, however, mycorrhizal colonisation of the salt-stressed plants restored leaf nutrient concentrations to the levels in non-stressed plants in most cases. AM inoculation improved pepper growth under salt or saltless conditions and reduced cell membrane leakage.