A forum for discussion of potential collaborations with regards to plant growth and culture – i.e. propagation, root growth, water management, weed control, PGRs, plant nutrition, etc.
Investigating the Effect of Pecan Rootstock on Rhizosphere Soil and Root Microbial Communities - Xinwang Wang Enhancing Urban Food Production: A Multi-Omics Investigation of Microbe-Mediated Soil Improvement and Plant Nutrition in New York City Farms - Yejin Son The Effect of Reclaimed Water on Young Blueberry Seedling Root Architecture Using Rhizotron Technique - Yasmeen Saleem Root Characterization Analysis of Navajo Peach Seedlings - Reagan Wytsalucy Characterizing Root Dynamics and Phenology of Hops in a Subtropical Climate Using an In-situ Root Imaging System - Alvaro J. Bautista Effects of Reclaimed Water on Blueberry Seedling Growth and Root Morphology - Yasmeen Saleem
Pecans (Carya illinoinensis), the most valuable native North American nut crop, are commonly propagated through grafting to maintain desired traits from parent trees. Successful pecan cultivation relies on scion varieties, rootstocks, and soil conditions. This study investigated the microbial abundance and diversity in soils and roots of a southern rootstock (87MX5-1.7) and a northern provenance ('Peruque') in a rootstock test orchard, both grafted with a 'Pawnee' scion cultivar in the USDA ARS Pecan Breeding program. The 16S ribosomal RNA of bacteria and ITS of fungi were sequenced and annotated into trophic and nutrient-related groups to characterize the rhizosphere microbiota. The results showed fungal dominance over bacteria, with Peruque roots having a higher relative abundance of saprotroph fungi compared to 87MX5-1.7, while 87MX5-1.7 exhibited higher levels of nitrogen fixation-related bacteria. Despite no significant difference in diversity index, the presence of symbiotrophs, especially the ectomycorrhizal fungi, exhibited distinct ectomycorrhizal fungi, which may lead to a divergent pathway of nutrient translocation between these two rootstocks. The study suggests rootstocks from different origins shape rhizosphere microbiota differently, affecting nutrient uptake and potentially nut yield. Exploring rootstock-fungi combinations could enhance grafting success and ultimately increase nut yield.
Urban agriculture (UA) is an emerging food production system in which farmers grow crops within cities. However, many urban farmers face challenges with their compost soils, including poor soil structure and low nutrient availability. This study aimed to utilize beneficial microbes, such as arbuscular mycorrhizal fungi (AMF) and phosphorus solubilizing bacteria (PSB), to address soil aggregation and biological phosphorus (P) cycling in UA soils while also assisting urban farmers in generating higher economic returns. We cultivated Bush Champion II Hybrid Tomatoes (an indeterminate tomato cultivar) in three organic urban farms in New York City in 2022 under four different treatments: 1) Control tomatoes, which were not treated with PSB or AMF; 2) Tomatoes treated with PSB; 3) Tomatoes treated with AMF; and 4) tomatoes treated with PSB and AMF. Our hypothesis posited that the positive interactions of PSB and AMF would synergistically enhance soil phosphorus cycling and carbon accumulation and, thereby, promote plant growth and nutrition. Our findings indicate that the combined application of AMF and PSB increased the overall abundance of soil microbiomes, as measured by flow cytometry. There was also an increase in the production of soil-aggregating proteins and soil acid phosphatase activity. Additionally, the nutrient uptake by tomatoes, including calcium (Ca), potassium (K), and phosphorus (P), was enhanced. We also employed omics approaches using deep sequencing metagenomics and metaproteomics to generate meaningful insights into how AMF and PSB interacted with soil native microbial populations and defined soil microbiome functions. Our findings offer novel insights into the characteristics and functions of soil microbiomes in UA soils. This knowledge will contribute to advancing the potential of beneficial microbes in enhancing food production within urban agriculture systems.
Southwest Native American Tribes, such as the Navajo, Hopi, and Pueblo, have grown peaches at least since the early 1600’s, making them a nutritionally and culturally important food source. Historic management practices consisted of reduced irregular irrigation of sandy to sandy loam soils with no fertilizer additions, no pruning, and no fruit thinning. Recent research indicates germinated peach seedlings from seed sourced from a Navajo orchard in Utah are more drought resistant when compared to direct seeded ‘Lovell’ seedlings, and container transplanted ‘Lovell’ seedlings. The purpose of this study was to characterize the Navajo seedlings’ root distribution after direct seeding to better understand their rooting dynamics with regular irrigation and no pruning. All trees were direct seeded in May 2018 and destructively sampled in May 2022. Three trees from each Navajo and ‘Lovell’ treatment were destructively harvested to determine above ground biomass. Root distribution (location relative to the trunk and depth in the soil profile) was determined using a soil core sampling technique. Soil cores were taken in a radial array around the tree, and tree roots (small, medium, large) were separated from the soil cores in the field, before drying and weighing. After the cores were extracted, the remaining root system was excavated, air dried for 10 days, then weighed and photographed. The main effect and interactions of tree type, sampling location, and depth were tested by analysis of variance. The Navajo seedlings had a more extensive root system, including more roots in the grass alleyways, than Lovell seedlings indicating a more competitive root system. There were also qualitative differences in root types between Navajo and ‘Lovell’ in the occurrence of lateral primary roots, sinker roots or fibrous roots. The results of this research will be utilized to determine the Navajo seedlings’ potential for becoming a viable rootstock for the fruit industry.
In Florida's subtropical climate, photoperiod manipulation facilitates a unique production system for hops (Humulus lupulus L.), an important crop for the brewing industry, with two growth cycles per year. The spring season spans from mid-February to early June, immediately followed by the fall season, which concludes in late November. With contrasting climatic conditions, plant phenology, yield, and cone quality differ dramatically between the two growing seasons. To gain insights into the roles of roots in the seasonal differences in plant phenology and performance, we characterized root dynamics and phenology of 'Cascade' hops grown in West Central Florida using an in-situ root imaging system. The soil at the study site was Myakka fine sand with 97% sand. Plants were grown on a 4.5 m V-trellis system, and data were collected over 2 years upon transplanting. Minirhizotron tubes were installed at varying distances (0, 30, and 60 cm) from the planting hill perpendicularly to the row to capture biweekly root images up to a depth of 84 cm. These images were processed using WinRhizo Tron software to measure various root morphological parameters, including total root length, projected area, surface area, volume, and the longest root. Notably, hop roots showed rapid elongation, reaching a depth of 84 cm, and expanding up to 60 cm from the hill center within one month after establishment under subtropical conditions. However, the primary, larger in diameter tap roots exhibited signs of decay after 5 months, culminating in complete mortality within 15 months following their establishment. Interestingly, the phenological stage of cone development induces a proliferation of new root growth, although temporary, with these ephemeral roots having a lifespan limited to approximately 3 months. These results can provide insights into the shoot-root interactions and help improve fertilizer, water, and ground cover recommendations, ultimately optimizing hop production in Florida's unique subtropical system.
A high percentage of agricultural production depends highly on groundwater irrigation. Groundwater depletion has been putting significant pressure on global water resources and food production. Using reclaimed water (RW) as an alternative source of irrigation water for crop production can mitigate the huge demand on groundwater resources. Blueberry plants are characterized by their preference for acidic soil conditions with a shallow, salt-sensitive root system. The alkaline and saline nature of RW necessitates an understanding of its suitability as irrigation water for blueberry production. We conducted a greenhouse rhizotron experiment to characterize root morphological responses of ‘Arcadia’ blueberry seedlings to RW. Four irrigation water treatments were implemented: 100% well water (WW), 100% deionized water (DW), a blend of 50% DW/50% RW, and 100% RW. These treatments were applied to rhizotron boxes filled with 50% sand and 50% pine bark mixed uniformly by volume. Root morphological variables, stem diameter, plant height, canopy projected area, and plant physiological variables were examined biweekly. Soil and plant tissue nutrient contents and plant biomass were examined at the end of the experiment. Water quality was slightly alkaline with pH values of 7.8 for 100% WW and 100% DW, and 7.7 for 100% RW. Electrical Conductivity (EC) values varied among the treatments, with 0.428 dS/m for 100% WW, 0.338 dS/m for 100% DW, and 0.769 dS/m for 100% RW. Initial soil mix pH at the beginning of the experiment was 6.8. Our preliminary findings indicate no significant difference in root elongation, plant above-ground biomass and leaf chlorophyll index among the four irrigation treatments (p > 0.05). A significant difference was observed between DW and WW for plant stem diameter and height (p > 0.05), possibly attributed to blueberry plants’ sensitivity to salt. The soil mix pH had risen to 7.8 for all the treatments at the end of the experiment. Our preliminary interpretation suggests that 100% RW does not adversely affect young blueberry plants growth parameter over the short-time period of the experiment. That indicates that RW can be a promising alternative of irrigation. Existing literature indicates that blueberry plants have the ability to adopt to irrigation water EC level of up to 2 dS/m, while the measured EC of 100% RW was 0.77 dS/m, it appears that the blueberry plants didn’t reach to the stress level that could significantly affect their growth parameters. We believe the experiment duration was insufficient to observe the high pH symptoms.
