Shade House Research Articles

Physiological and biochemical changes in desiccation and rehydration cycles of Selaginella convoluta (Selaginellaceae)

Abstract Vegetative desiccation tolerance (VDT) is a biological process that allows resurrection plants to complete desiccation-rehydration cycles and survive without permanent damage. Physiological and biochemical changes related to the VDT were evaluated in the lycophyte Selaginella convoluta from the Caatinga biome, a seasonally dry tropical forest of northeastern Brazil. As representative of the oldest division of extant vascular plants, the investigation of VDT mechanisms in this species serves as an opportunity to provide information for research communities interested in functional traits related to water-limited conditions. The experiments were performed with plants in their natural habitat, in dry and rainy seasons, and in pots under shade house conditions. Relative water content, chlorophyll a fluorescence, gas exchange, activity of antioxidant enzymes, concentration of chlorophylls, proteins, total amino acids, proline, and soluble carbohydrates in leaf tissues were evaluated throughout the process of complete dehydration and subsequent re-watering of intact plants. The overall results reveal the capacity of S. convoluta to tolerate extreme dehydration and rapidly recover upon rehydration. This species minimizes potential damages during the desiccation-rehydration cycle due to the presence of inductive mechanisms (photochemical preventing, sucrose accumulation) and constitutive mechanisms (antioxidant activity of catalase and ascorbate peroxidase), which share similarities with the VDT of both angiosperms and bryophytes.

Phosphorus limitation of early growth differs between nitrogen-fixing and nonfixing dry tropical forest tree species.

Tropical forests are often characterized by low soil phosphorus (P) availability, suggesting that P limits plant performance. However, how seedlings from different functional types respond to soil P availability is poorly known but important for understanding and modeling forest dynamics under changing environmental conditions. We grew four nitrogen (N)-fixing Fabaceae and seven diverse non-N-fixing tropical dry forest tree species in a shade house under three P fertilization treatments and evaluated carbon (C) allocation responses, P demand, P-use, investment in P acquisition traits, and correlations among P acquisition traits. Nitrogen fixers grew larger with increasing P addition in contrast to non-N fixers, which showed fewer responses in C allocation and P use. Foliar P increased with P addition for both functional types, while P acquisition strategies did not vary among treatments but differed between functional types, with N fixers showing higher root phosphatase activity (RPA) than nonfixers. Growth responses suggest that N fixers are limited by P, but nonfixers may be limited by other resources. However, regardless of limitation, P acquisition traits such as mycorrhizal colonization and RPA were nonplastic across a steep P gradient. Differential limitation among plant functional types has implications for forest succession and earth system models.

Assessment of Yield and Quality Attributes of Garden Pea (Pisum sativum. L) Varieties under Shade House Condition

The present study investigated the yield potential of fifteen varieties of Garden pea from various sources across the country. As there is no specific high yielding genotype of Garden pea recommended for cultivation in Bangalore region, which is located on the Deccan plateau, it is a main challenge to identify a suitable high yielding genotype for southern region of Karnataka so as to recommend for similar situations. The varieties were evaluated for yield and quality attributes at Department of Horticulture, College of Agriculture, UAS, GKVK, Bengaluru, India between October- January 2019-20 and 2020-21. Most of the major yield and quality contributing characters were significantly differed in the experiment. Experiment was carried out by using Randomized complete Block Design out of the fifteen varieties tested, highest pod length (10.98 cm), pod weight (9.38 g), pod width (2.87 cm), number of pod per plant (19.35), yield of pods per plant (92.62 g), per plot (3.15 kg), per hectare (157.50 q ha-1 tonnes) were recorded in T10 (Arka Apoorva), and number of green peas per pod (9.87), were recorded in T9 (Arka Karthik). Whereas T3 (Kashi Nandini) produced the days to first flower (41.56), and days to fifty percent flowering (52.08) were observed in T7 (PSM-4). Garden Pea being one of the most suitable vegetable crops for Rabi cultivation, the identified varieties could be raised by the farming community of the region for enhanced yield and economic benefits.

Effect of Integration Vermicompost and Nano-Fertilizer on Fig Seedlings Growth and Soil Health

This study was conducted with the aim of making a new approach to plant fertilization based on nano-fertilizers and vermicompost and its positive effect on soil health. This work was carried out in the experimental research shade house of National Research Centre, Dokki, Giza, Egypt during (2020- 2021). For this purpose, healthy 5 years old fig seedlings sultani cultivar. The seedlings were planted in black polyethylene pots with 30 cm diameter fooled. with use 10 kg washed sand mixed very good with use three concentrations of Vermicompost 500 -1000 and 1500g/seedling ,with adding varied doses of Nano-NPK(20:20:20) fertilizers (200, and 400ppm) as foliar application. Nano-NPK fertilizers treatments were applied two times monthly during active season, also fig seedlings were irrigated twice weekly .At the end of each growth season, leaves were collected to record some vegetative parameters (leaf fresh and dry weight and leaf area) then these samples of leaves were dried and digested to determine nutrient statues under tested treatments. Moreover, Estimation of microbial and enzymatic activities of vermicompost. Obtained results indicated that, substituting half recommended dose of spraying with Nano-fertilizers at (400 ppm) positively promote most of recorded vegetative growth parameters and without any deficiency symptoms on seedlings. Also, The microbial and enzyme activities of the soil are closely related to the organic matter content and influenced by all practices applied for soil including adding fertilizers, emphasize these impacts of organic matter as vermicompost and nano-fertilizers. Besides, all treatments (vermicompost + nano-fertilizers) resulted in increasing enzyme activity comparing with control treatment. Also, indicated that at the same level of nano-fertilizers, increasing vermicompost dosses lead to increase enzyme activity particularly in level 200ppm of fertilizers.

Pengaruh Pemberian Dosis Pupuk Hayati Mikoriza pada Pertumbuhan Bibit Dua Varietas Kelapa Sawit di Pembibitan Awal

This study aims to determine the best dose of mycorrhizal biological fertilizer for palm oil seedling growth of DxP Simalungun and DxP Sriwijaya 2 varieties in the pre-nursery stage. This research was carried out by the shade house of the Faculty of Agriculture, Sriwijaya University, Indralaya, Ogan Ilir, from October 2020 to January 2021. The study used the Completely Randomized Design method consisting of eight treatments and four replications, in which there were three plants in each experimental unit. The treatment provided consists of A (Simalungun without mycorrhizal), B (Simalungun given 5 g of mycorrhizal), C (Simalungun given 10 g of mycorrhizal), D (Simalungun given 15 g of mycorrhizal), E (Sriwijaya 2 without mycorrhizal), F (Sriwijaya 2 given 5 g of mycorrhizal), G (Sriwijaya 2 given 10 g of mycorrhizal), and H (Sriwijaya 2 was given 15 g of mycorrhizal). The results showed that the treatment of mycorrhizal biofertilizer with a dose of 5 g is the best treatment to the height of seedlings, the number of leaves, the leaf greenness index, the total leaf area, the diameter of the seedlings, the number of roots, the length of roots, and the dry weight of seedlings. The Sriwijaya 2 variety is more responsive to the provision of mycorrhizal biofertilizers.

Propagation of “Valencia” orange (Citrus x sinensis Osbeck) by minigraft

Demand for citrus (Citrus spp) plants for commercial orchards has increased worldwide due to the need for new plantations, renewal of disease-effected crops, and strict regulation for plant production. To evaluate faster and low-cost propagation alternatives for citrus, “Valencia” orange plants were propagated by using two minigrafting techniques (Cleft and inverted T-budding). Rootstocks were raised from “Cleopatra” mandarin seeds, and scions and buds were isolated from 1-year-old grafted plants. For cleft minigrafts, scions were inserted at 5-7 cm height inside of the decapitated rootstocks and covered with Eppendorf® tubes. For T-budding, buds were inserted at 5-7 cm height under the rootstock cortex cut. Unions were fixed with Parafilm®. Grafted plants were maintained under a shade house (50%) with two daily fog irrigation (2 min each). Treatments were distributed with a completely randomized design. Six weeks after grafting, the percentage of success, the shoot length, and the number of leaves per treatment were registered and analyzed with a T test (α=0.05). Cleft minigraft resulted in a higher success percentage and plants with larger shoots. Cleft minigraft could be considered an alternative for citrus propagation in small and medium size nurseries.

First Report of Colletotrichum truncatum Causing Anthracnose of Guar (Cyamopsis tetragonoloba) in Mexico.

Guar (Cyamopsis tetragonoloba), is an annual legume belonging to the Fabaceae family and it is grown mainly for industrial purposes and also as an ingredient for animal feed. In September 2021, anthracnose symptoms were observed on guar fields distributed in Guasave, Sinaloa, Mexico. Disease incidence was estimated up to 15%. Diseased plants exhibited symptoms on leaves and pods. On leaves, lesions were irregular, necrotic, and often surrounded by a dark brown halo. On pods, necrotic and sunken lesions were developed. Colletotrichum-like colonies were consistently isolated on PDA medium and five monoconidial isolates were obtained. One isolate was selected as representative for morphological characterization, multilocus phylogenetic analysis, and pathogenicity tests. The isolate was deposited in the Culture Collection of Phytopathogenic Fungi of the Faculty of Agriculture of Fuerte Valley at the Sinaloa Autonomous University under the accession number FAVF642. Colony on PDA was flat with an entire margin, dense, initially grayish white, then became dark gray with black microsclerotia and setae. Conidia (n= 50) were curved, hyaline, aseptate, with granular content, and measuring 20.4 to 25.8 × 2.8 to 3.9 μm. Setae were dark brown, straight, and septate. Morphological features matched those of Colletotrichum truncatum (Damm et al. 2009). For morphological identification, total DNA was extracted, and the internal transcribed spacer (ITS) region (White et al. 1990), and partial sequences of actin (ACT), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes were amplified by PCR (Weir et al. 2012), and sequenced. The resulting sequences were deposited in GenBank under the accession nos. OM616022 (ITS), OM630461 (ACT), and OM630462 (GAPDH). BLASTn searches in GenBank showed 100%, 99.49%, and 99.15% identity to MT583079 (ITS), MG198003 (ACT), and MG703491 (GAPDH) of C. truncatum, respectively. A phylogenetic tree based on maximum Likelihood method and including published ITS, ACT, and GAPDH sequence data for Colletotrichum truncatum species complex was generated (Talhinhas and Baroncelli 2021). In the phylogenetic tree, the isolate FAVF642 was placed in the same clade of C. truncatum. Pathogenicity of the isolate FAVF642 was verified on 10 guar seedlings (15-day-old) by spraying a conidial suspension (1 × 106 spores/mL) onto leaves until runoff. Five plants noninoculated served as controls. All plants were kept in a moist chamber for 2 days, and subsequently transferred to a shade house where the temperature ranged from 20 to 30°C. The experiment was conducted twice with similar results. All inoculated leaves developed irregular and necrotic lesions 8 days after inoculation, whereas no symptoms were observed on the control leaves. The fungus was consistently re-isolated from the diseased leaves, fulfilling Koch´s postulates. Colletotrichum truncatum has been previously reported to cause guar anthracnose in India (Farr and Rossman 2022). To our knowledge, this is the first report of C. truncatum causing guar anthracnose in Mexico. This disease is an emerging problem in guar fields in Sinaloa, therefore further studies are required to understand its occurrence and impact in Mexico.

Effect of Different Inorganic Fertilizers on Growth and Development of Dieffenbachia seguine (Jacq.) Schott

A shade house (75%) experiment was carried out to determine the effect of different levels of NPK on growth and development of Dieffenbachia seguine (Jacq.) Schott plants at College of Horticulture, Rajendranagar, Hyderabad, Sri Konda Laxman Telangana State Horticultural University during Kharif season of the year 2019-20 in Completely randomized design with seven treatments and replicated thrice. The results revealed that different levels of NPK significantly influenced the Dieffenbachia plants growth and development. Among different inorganic fertilizer treatments, application of N:P:K (1:1:1) – 2 g per poly bag at 30 days interval (T1) significantly recorded maximum plant height (76.00 cm), growth rate in respect of plant height at 45, 90 and 135 days interval (2.01, 2.50 and 3.07 cm/day respectively), plant spread (E-W) (59.00 cm), stem diameter (37.63 mm) and number of leaves per plant (7.33).

Pesticide management and farmers perception of environmental and health issues due to pesticide use in the state of yucatán, mexico: A study case

Agriculture in the Yucatán Peninsula, Mexico, grew last year, and pesticide use problems have been reported; however, there is no information about the use and management of pesticides in farms. In this study, the main pesticides used by farmers were identified in two types of agriculture: open-air (milpa) (OA) and enclosed area (shade house and greenhouse) (EA), in order to evaluate their use and management and the related environmental and health perceptions of users. Surveys (38 questions) were applied to 39 farmers in the study area, which consisted of 14 localities in Yucatán State. The most cultivated products were habanero pepper (Capsicum chinense) for enclosed-areas and maize (Zea mays) for open-air agriculture. The use of 33 active ingredients was reported. Some of them have restrictions in México (i.e., dicofol and methamidophos). Paraquat was the most used of all pesticides reported. Organophosphorus pesticides (OP) were the most used. Farmers know about the environmental and health risks related to pesticide use; however, a lack of knowledge about the misuse of these products was evident. The surveys showed deficiencies in personal protection during application and incorrect disposal of empty containers and wastes. The analysis showed that the behavior of farmers about pesticide management and their perception of damage to health and the environment were multifactorial. The results conclude that farmers’ personal aspects (i.e., language, education) are the leading cause of problems associated with pesticide misuse and the lack of information and training, representing a risk for human health and the environment.

Growth dynamics of container seedlings of Eucalyptus grandis x Eucalyptus urophylla and Hymenaea courbaril L.

Growth analysis (GA) is used to quantify plant development based on morphophysiological changes. GA is a practical tool to evaluate nursery techniques to make them more efficient. The objective of this essay was to quantity measure morphophysiological growth variables of Eucalyptus grandis x Eucalyptus urophylla and Hymenaea courbaril (jatoba) container seedlings to characterize growth stages. The essay was conducted in a shade house located in the western state of Paraná. GA analyses were performed at 10-day intervals on seedlings of both species. When evaluating Hymenaea courbaril seedlings results indicated ​​increased values of height, diameter, root and shoot dry biomass up to 130 days after emergence (DAE). Seedling growth stage-based GA were 70, 100 and 130 DAE for the Eucalyptus hybrid and 50, 80, and 110 DAE for jatoba which presented accelerated, intermediate and reduced seedling growth.

STUDY OF EFFECTIVITY Bacillus thuringiensis BASED BIO-INSECTICIDE AGAINST Oryctes rhinoceros LARVAE AT SHADE HOUSE

Oryctes rhinoceros is an important pest in oil palm plantations. Adult stage of the beetle causes damage, however larval stage is very important to be controlled to break the cycle of life. An entomopathogenic bacterium Bacillus thuringiensis is one of biological agents to control these insects. Its toxic protein content provides specific insect targets as stomach poison. Objectives of the research was to study the impact of B. thuringiensis propagated in bio-urine enriched with 5 per cent molasses towards Oryctes larvae. The research was carried out in the shade house of Plant Protection Study Program, Faculty of Agriculture, Sriwijaya University from August to November 2021. Experiment was designed in a randomized complete block design with 7 treatments and 4 replications. A total of 20 ml of bio-insecticide was dissolved in 280 ml of water, sprayed evenly on the soil mixed with male palm flowers as feed of larvae. The treatments were 6 isolates of B. thuringiensis isolated from soil in oilpalm plantation, namely with codes: C14, C15, A15, OJ, BK, and LK as well. The results showed density of B. thuringiensis spores in bio-urine media was different in each isolate. The highest spore density in isolate code LK was 4.83 x 1010 spores/ml and the lowest (in isolate A15) was at 3.5 x 1010 spores/ml. Mortality rates were significantly different between isolate treatments starting from day 3 to day 12 of observation. C15 isolate lead the highest mortality rate of 100% on day 12 while other isolates showed mortality data below 100% (88-98%). Body weight and length showed significantly differences on days 0, 6 and 12 after application. Symptoms of infection begin with a change in skin color from white to brown, dark brown and black. Death is characterized by a soft body texture and wet rot.

Plastic Responses in Growth, Morphology, and Biomass Allocation of Five Subtropical Tree Species to Different Degrees of Shading

We investigated how different degrees of shading affected growth, morphology, and biomass allocation in seedlings from two coniferous and three broadleaved species. The experiment was conducted in a shade house over a 1-year period. Our results showed that under increasing shade, seedlings from most species exhibited lower total biomass, net assimilation rates, relative growth rates, root mass ratios, and root/shoot ratios. In contrast, the slenderness quotients, leaf area ratios, and specific leaf areas increased with increasing shade. For coniferous species, growth traits were relatively more plastic (responsive to shade) than morphology or biomass allocation traits, whereas for broadleaved species, growth and biomass allocation were the most shade-sensitive traits. When comparing coniferous versus broadleaved species, the former had a higher growth plasticity index and lower allocation plasticity than the latter. Root biomass and stem mass ratio were the most and least plastic traits in response to shading. Our results indicate that shade differentially affects coniferous and broadleaved species in terms of their growth, morphology, and biomass allocation. These findings have important implications for the establishment and maintenance of mixed-species stands.

Rapid Identification of Western Flower Thrips, Frankliniella occidentalis (Thysanoptera: Thripidae) in Shade Houses in Western Cape of South Africa

The western flower thrips (WFT), Frankliniella occidentalis (Pergande) (Thripidae: Thysanoptera), is one of the most economically important pests in shade houses. However, their identification is usually difficult, with them being easily confused with other thrips species. Accurate, rapid and reliable identification of insect pests is a crucial first step in implementing an efficacious management program. In this study the identity of F. occidentalis was verified, using molecular methods using the mtCOI gene sequences. Molecular analysis of thrips specimens collected from chrysanthemums and blueberries in the Western Cape Province, South Africa revealed the presence of Frankliniella. occidentalis and four other thrips species. Two of the five the specimens were F. occidentalis and one of the specimens was identified as Gynaikothrips ficorum. The remaining specimens were identified only to a generic level as Pseudophilothrips sp and to an ordinal level as Thrips sp. Failure to identify the two specimens to specific levels might have resulted from lack of sequences of identified thrips species in the molecular data bases. Considering the speed, specificity as well as sensitivity of the method, mtCOI sequences can be used as a swift and efficient method for western flower thrips identification and detection of new thrips pest invasion.

Biological control of Sclerotinia minor attack on pyrethrum plants by Trichoderma harzianum in glasshouse experiment

Abstract. Ramona Y, Darmayasa IBG, Line MA. 2022. Biological control of Sclerotinia minor attack on pyrethrum plants by Trichoderma harzianum in glasshouse experiment. Biodiversitas 23: 3264-3269. The aim of this research was to elucidate the efficacy of Trichoderma harzianum (isolate Td22) grown in a ratio of 2:8 millet seeds and wood fiber waste (WFW) compost mixture to suppress Sclerotinia minor infection in pot trails on the pyrethrum plants (in 0.5 L pots). The pots were filled with soil and mixed with Td22-grown WFW compost to obtain a concentration of 5% v/v. The S. minor (fungal pathogen) previously grown in millet seeds amounted at 2.0 g per pot, was then evenly inoculated at 2 cm below the surface of potting mix. Soil without compost amendment, amended with pathogen only, or without pathogen inoculation served as controls. All pots were acclimatized for 4 days in a shade house prior to transplanting (4 seedlings per pot) of pyrethrum seedlings (aged of 3 weeks). Eight replications per treatment were run for 8 weeks. The results showed that 5% v/v compost-grown Td22 provided 78% protection to pyrethrum plants at week 8. Each surviving plant in Td22-treated pots also showed significantly higher average dry weight (p<0.05) than those planted in S. minor control treatment, indicating that Td22 has a potential to be developed as a novel fungal antagonist or a plant growth-promoting fungus.

First Report of Citrus Virus A in Texas Associated with Oak Leaf Patterns in Citrus sinensis.

In 2018, Navarro et al. (2018a, b) identified two new negative sense coguviruses in citrus, citrus concave gum-associated virus (CCGaV) and citrus virus A (CiVA). Since then, the members of the genus Coguvirus have been also detected in other plant species (Xin et al. 2017; Wright et al. 2018; Svanella-Duma et al. 2019). In 2016, leaf flecking with oak leaf patterns were observed in five plants among embryo-rescued navel orange (NO) (Citrus sinensis (L.) Osbeck) trees grafted on C22 (C. sunki x Poncirus trifoliata) rootstock, maintained in a shade house. Madam Vinous (MV) sweet orange trees graft-inoculated with blind buds from the symptomatic NO plants developed the same symptoms in the new growth. These symptoms were similar to those on the citrus concave gum (CG) source tree of the California isolate CG301, one of the standard citrus disease isolates used as a positive control for biological indexing (Roistacher et al. 2000). None of the trees with oak leaf symptoms tested positive with reverse transcription (RT)-PCR for a panel of viruses and viroids commonly infecting citrus (Table S1) . In this study, CG301 leaf RNA-Seq data was used as a platform to identify any viral agent(s) associated with the oak leaf symptoms observed in the symptomatic NO trees (Fig. S1). Of ~162.8 million paired-end CG301 RNA-Seq reads (150 bp), de novo assembly of ~9.6 million reads, not mapped to C. sinensis genome (v.1.1), yielded 5,375 contigs. BLASTn using NCBI virus database (txid 10239) identified two contigs, #49 (6,715 nt) and #20 (2,764 nt), which exhibited ~96% sequence identity, respectively, to RNA1 and 2 of CiVA isolate W4 (MG764565; MG764566) and 71-73% identity to that of CCGaV isolate CGW2 (KX960112; KX960111). 5'-Nuclease assay developed based on contig #20 detected coguviral sequences in the five symptomatic NO and graft-inoculated MV trees as well as in CG301 but not in 44 asymptomatic field trees located near the shade house where the symptomatic NO trees had been kept. A full genomic sequence of the coguviruses present in CG301 and a symptomatic NO tree was reconstructed by RT-PCR. Both CG301 and NO isolate have a 6689 nt long negative sense RNA1 (MT922052; MK689372) encoding RNA-dependent RNA polymerase (RdRp) and a 2739 nt long ambisense RNA2 (MT922053; MK689373) encoding movement protein (MP) and nucleocapsid protein (NP). The isolate CG301 and NO share ~96% nucleotide sequence identity. The genome of both CG301 and NO isolate share 95.4-97.8 % sequence identity to that of CiVA isolate W4 and 70-72.9 % sequence identity to CCGaV isolate CGW2. BLASTp showed that RdRp of CG301 and NO isolate have 96.3-97.7 % sequence identity to CiVA W4 RdRp and ~77 % to CCGaV CGW2 RdRp. These data indicated the presence of CiVA in the symptomatic NO trees and in the concave gum source tree CG301. Recent reports of CiVA in South Africa and Greece indicated a potential wider distribution of CiVA in various citrus growing regions that may be associated with two graft-transmissible citrus diseases, citrus concave gum and impietratura disease (Roistacher et al. 2000; Velázquez et al. 2019; Beris et al. 2021; Bester et al. 2021). Although the source of CiVA in the symptomatic NO trees and the degree of CiVA prevalence in Texas had not been determined yet, a possible involvement of vector(s) or other means of spread (e.g. seed transmission) cannot be ruled out (Timmer et al. 2017). The current study demonstrated the need for further studies to determine the level of threat of coguviruses for citrus production in Texas.

Palm Species Traits Determine Soil Nutrient Effects on Seedling Performance

Environmental gradients influence plant establishment, survival, and functional traits. Along the Panama Canal Isthmus there is a strong rainfall gradient with an underlying mosaic of soil types ranging in soil nutrient availability. In this region, tree species distribution patterns are correlated with soil phosphorus availability and rainfall patterns, but how understory plant species such as palms relate to these factors is less clear. We hypothesized that due to greater resource use efficiency and optimal biomass allocation, specialist species will have greater seedling performance growing in home soil and sites compared to species not occurring there. To test this hypothesis, we used two specialist species (Chamaedorea tepejilote and Geonoma congesta) and two generalist species (Geonoma cuneata var. cuneata and Chamaedorea pinnatifrons), and for these four species we measured traits on seedlings and assessed their performance in shade house and field transplant experiments using five soils. Soils were sourced from five sites which varied in nutrient availability and rainfall, and were distributed along lowland tropical forests of the Panama Canal Isthmus. In the shadehouse experiment, leaf functional traits were determined by species rather than soil nutrient availability. However, in the shadehouse experiment, seedling biomass allocation, and relative growth rate were determined by interactions between species and soil, with weak support for home-site advantage for one of the species. In the field transplant experiment, seedling survival was strongly related to dry season water availability. However, species tended to have high survival at home sites and other sites with higher dry season rainfall. Together, results from these experiments suggest that understory palm species seedling performance are determined by species-specific responses to the combination of soil nutrient and water availability. This indicates that while soil nutrients influence seedling biomass allocation, dry season water availability determines both specialist and generalist seedling survival and therefore distributions along the soil nutrient and moisture gradient.

The Evaluation of Different Concentrations of Moringa leaf extract on Vegetative and Reproductive Performance of Tomatoes

This study sought to evaluate the effects of different concentrations of M-L-E on the vegetative and reproductive performance of tomatoes. A pot study was conducted for a period of 13 weeks under a shade house. This experiment design was a Completely Randomized Design (CRD) with five replicates and four treatments. The treatments were -T1 (control using 15:15:15), T2 (moringa extract at 25%), T3 (moringa extract at 50%) and T4 (moringa extract at 75%).

Effect of Glyphosate and Carbaryl Applications on Okra (Abelmoschus esculentus) Biomass and Arbuscular Mycorrhizal Fungi (AMF) Root Colonization in Organic Soil

Pesticide application in horticultural crops has recently multiplied to increase crop yields and boost economic return. Consequently, the effects of pesticides on soil organisms and plant symbionts is an evolving subject of research. In this short-term study, we evaluated the effects of glyphosate (herbicide) and carbaryl (insecticide) on okra biomass and AMF root colonization in both shade house and field settings. An additional treatment, the combination of glyphosate and carbaryl, was applied in the field trial. Soil and root samples were collected three times during the experiment: 30 days after planting (before first spray, or T0), 45 days after planting (before second spray, or T1), and at full maturity (at 66 days after planting, or T2). Our results indicate that glyphosate and combined treatments were most effective in controlling weeds and produced almost 40% higher okra biomass than the control. There was a ~40% increase in AMF root colonization in glyphosate-treated plots from T0 to T1. This result was likely due to high initial soil P content, high soil temperature, and low rainfall, which aided in the rapid degradation of glyphosate in the soil. However, at T2 (second spray), high rainfall and the presence of excess glyphosate resulted in a 15% reduction in AMF root colonization when compared to T1. We found carbaryl had little to negligible effect on AMF root colonization.

Biochemical and Histological Insights into the Interaction Between the Canker Pathogen Neofusicoccum parvum and Prunus dulcis.

The number of reports associated with wood dieback caused by fungi in the Botryosphaeriaceae in numerous perennial crops worldwide has significantly increased in the past years. In this study, we investigated the interactions between the canker pathogen Neofusicoccum parvum and the almond tree host (Prunus dulcis), with an emphasis on varietal resistance and host response at the cell wall biochemical and histological levels. Plant bioassays in a shaded house showed that among the four commonly planted commercial almond cultivars ('Butte', 'Carmel', 'Monterey', and 'Nonpareil'), there was no significant varietal difference with respect to resistance to the pathogen. Gummosis was triggered only by fungal infection, not by wounding. A two-dimensional nuclear magnetic resonance and liquid chromatography determination of cell wall polymers showed that infected almond trees differed significantly in their glycosyl and lignin composition compared with healthy, noninfected trees. Response to fungal infection involved a significant increase in lignin, a decrease in glucans, and an overall enrichment in other carbohydrates with a profile similar to those observed in gums. Histological observations revealed the presence of guaiacyl-rich cell wall reinforcements. Confocal microscopy suggested that N. parvum colonized mainly the lumina of xylem vessels and parenchyma cells, and to a lesser extent the gum ducts. We discuss the relevance of these findings in the context of the compartmentalization of decay in trees model in almond and its potential involvement in the vulnerability of the host toward fungal wood canker diseases.

Improved native understorey establishment in mine waste rock in Australia’s wet–dry tropics

Re-establishment of understorey in mine waste can be challenging because of its physical, chemical and microbiological characteristics. This project investigated amelioration treatments for establishing native understorey in waste rock at Ranger uranium mine, including the addition of fine sand, fertiliser, surface litter, incorporated organic matter, or a combination of sand, fertiliser and litter. Trials were established in a shade house and in situ on a waste-rock landform. Several grass and legume species had seedling emergence and growth being monitored. In situ, surface litter generally had twice as many seedlings emerge as did the other treatments and had the tallest mean height for most species, likely because it created a microclimate that retained moisture and moderated temperature. In the shade house, no treatment had significantly greater emergence than the control (except Acacia gonocarpa F.Muell. with surface litter). Fertiliser application resulted in significantly taller plants in the shade house but had no effect in situ, which suggests that under well watered conditions, plant growth in waste rock is affected by nutrient deficiency, whereas in field conditions, water supply is the main growth-limiting factor. When establishing native understorey on waste rock in hot and seasonally wet–dry climates, applying surface litter with seeds may improve initial establishment.