The Effect of Polyamines and Silver Thiosulphate on Micropropagation of Date Palm Followed by Genetic Stability Assessment

There are some limitations in the practical applications of in vitro date palm tissue culture, such as low multiplication efficiency, low rooting rate, and high mortality experienced by in vitro raised plantlets during laboratory to soil transfer. This study’s objective was to investigate the effect of the two types of polyamines (putrescine "PUT" and spermidine" SPD") in combination with silver thiosulfate (STS) on the growth and development and genetic stability of cultures of Quntar cultivar. Media supplemented with 75 mg L−1 SPD in combination with 10 mgL−1 STS gave the highest percentage of callus producing buds (83.34%) and average bud formation (16.3) per jar. The addition of PUT and STS to the medium was most effective in root formation and the number of roots per shoot, where the best result 91.67% and 6.37 roots per shoot, respectively, were obtained using 75 mgL−1 PUT and 10 mgL−1 STS, resulting in fast-growing plantlets during acclimatization phase, reaching 90% of plant survival. The genetic fidelity assessment of plants derived from micropropagation was confirmed by RAPD analysis. Four operon primers were used, and all of them showed amplified unambiguous (OPA02, OPC-04, OPD-07, and OPE-15). All generated bands were monomorphic and had no variation among the tissue culture-derived plants tested. Accordingly, these results indicate that adding polyamines and silver thiosulfate to the nutrient medium of date palm cv. Quntar is beneficial in improving shoot organogenesis, rooting, and production of genetically stable date palm plants.

Caracterização hidrodinâmica e térmica de um solo de Mata Atlântica

As Caracterizações hidrodinâmica e térmica do solo são indispensáveis para subsidiar pesquisas relacionadas a análise dos processos de interação solo-planta-atmosfera. Deste modo, o intuito desta pesquisa é realizar a caracterização hidrodinâmica e térmica de um solo que compõe um fragmento de Mata Atlântica, localizado no bairro de Dois Irmãos, Recife, Pernambuco, Brasil. Para tanto, foram realizados ensaios laboratoriais de granulometria e ensaios de infiltração utilizando-se uma coluna de solo. Para obtenção dos parâmetros hidrodinâmicos seguiu-se a metodologia Beerkan Estimation of Soil Transfer (BEST), enquanto que as propriedades térmicas do solo foram obtidas a partir de modelos propostos por De Vries (1963). Após estes procedimentos, o solo em análise foi classificado como franco arenoso. Verificou-se que o BEST forneceu valores coerentes para os parâmetros de forma e de normalização das curvas de retenção da água no solo e de condutividade hidráulica. Com relação às propriedades térmicas do solo observou-se uma significativa variação com o aumento da umidade, ficando evidente que a água no solo desempenha um papel determinante na dinâmica da propagação do calor. Os valores das propriedades hidrodinâmicas e térmicas do solo, fornecidos pelos diferentes métodos empregados, encontraram-se dentro da faixa estabelecida na literatura.

Predição do escoamento superficial e consequentes alagamentos em centros urbanos

Os alagamentos são um problema em vários centros urbanos decorrentes da descaracterização natural do solo e do aumentando do escoamento superficial. A caracterização hidrodinâmica dos solos pode ser realizada por ensaios de campo ou laboratoriais visando a predição destes alagamentos. Sendo assim, objetivou-se estimar o escoamento superficial de água no solo por meio de simulações utilizando o Hydrus-1D, para explicar os alagamentos que ocorrem numa área urbana. Para obtenção dos parâmetros hidrodinâmicos seguiu-se a metodologia do Beerkan of Estimation Soil Transfer (BEST) realizada em laboratório com colunas de acrílico e dois solos distintos, enquanto que as simulações do escoamento superficial foram feitas com Hydrus-1D. Por meio das curvas de infiltração verificou-se que o solo menos arenoso possui uma capacidade de infiltração menor. A primeira simulação mostrou que o escoamento superficial cumulativo foi de 355,67 mm dia-1 enquanto que na segunda simulação o escoamento superficial acumulado foi de 362,03 mm dia-1. A realização dos ensaios de infiltração apenas na superfície do perfil do solo podem acarretar em resultados imprecisos, uma vez que a discrepância entre os valores simulados do escoamento superficial chegam a 105,14%. Deste modo, para uma estimativa de escoamento superficial mais precisa são necessários sucessivos ensaios de infiltração em diferentes profundidades.

Topsoil Transfer from Natural Renosterveld to Degraded Old Fields Facilitates Native Vegetation Recovery

The transfer of soils from intact vegetation communities to degraded ecosystems is seen as a promising restoration tool aimed at facilitating vegetation recovery. This study examined how topsoil transfer from intact renosterveld to degraded old fields improves vegetation diversity, cover, and composition. Transferred topsoil were overlaid on 30 quadrats, each measuring 1 m2, in May 2009. Eight years following the initial soil transfer, vegetation diversity in the soil transfer site showed an increase towards the natural site compared to the old field site where no soil transfer was administered. Both species richness and cover for trees and shrubs in the soil transfer site increased towards the natural site, though this was not the case for herbs and grasses. One-way analysis of similarity (ANOSIM) showed significant (R = 0.55) separation in community composition between sites. The study concludes that soil transfer from intact renosterveld to degraded old fields is a promising restoration technique because it increases species diversity and cover and facilitates vegetation recovery. A significant restoration implication of this study is that soil transfer introduces key renosterveld native tree and shrub species that can facilitate successful restoration and act as restoration foci or nurse plants.

A general BEST method predicting soil hydraulic parameters for any type of water retention and hydraulic conductivity curves

<p>Soil hydraulic characterization is crucial to describe the retention and transport of water in soil, but current methodologies limit its spatial applicability. This work presents a cost-effective general Beerkan Estimation of Soil Transfer parameters (BEST) methodology using single ring infiltration experiments to derive soil hydraulic parameters for any type of unimodal water retention and hydraulic conductivity functions. The proposed method relies on the BEST approach. The novelty lies in the use of Kosugi hydraulic parameters without need for textural information. Kosugi functions were chosen because they are based on physical principles (log-normal distribution for pore size distributions). A link between the Kosugi parameters (i.e., relationship between <em>σ</em> and <em>h</em><sub>kg</sub>) was introduced to reduce the number of parameters estimated and to avoid the need for information on the soil texture. This simplifies the procedures and avoids sources of errors related to the use of pedotransfer functions as for the previous BEST methods. Lastly, the method uses a quasi-exact formulation that is valid for all times, instead of the approximate expansions previously used, avoiding related inaccuracy and allowing the use of any infiltration data encompassing or not both transient and steady states. The new BEST methods were tested against numerically generated data for several contrasting synthetic soils, and the results show that these methods provide consistent hydraulic functions close to the target functions. The new BEST method is accurate and can use any type of water retention and hydraulic conductivity functions (Fernández-Gálvez et al., 2019).</p><p> </p><p> </p><p><strong>Reference</strong></p><p>Fernández-Gálvez, J., Pollacco, J.A.P., Lassabatere, L., Angulo-Jaramillo, R., Carrick, S., 2019. A general Beerkan Estimation of Soil Transfer parameters method predicting hydraulic parameters of any unimodal water retention and hydraulic conductivity curves: Application to the Kosugi soil hydraulic model without using particle size distribution data. Adv. Water Resour. 129, 118–130. https://doi.org/10.1016/j.advwatres.2019.05.005</p>

Testing sustained soil-to-soil contact as an approach for limiting the abiotic influence of source soils during experimental microbiome transfer

ABSTRACT Experimental separation of the biotic and abiotic components of soil will help in understanding the role of taxonomy and composition in soil microbiome function. The most common approach to soil microbiome transfer involves direct dilution of a non-sterile source soil into sterile recipient soils, introducing both microorganisms and soil compounds, leaving abiotic and biotic factors confounded. Here, we contrast microbiome transfer into sterile recipient soils through (i) direct soil transfer at two dilutions and (ii) a new approach, sustained contact between source and recipient soils. Sustained soil-to-soil contact retains separation between source and recipient soils, allows for multiple colonization events and increases confidence that microorganisms observed in recipient soils are active and growing. Each approach produced distinct microbiomes in recipient soils after 1 and 6 weeks of incubation, indicating that transfer method impacts microbial composition. The extent to which recipient microbiomes resembled source microbiomes varied by soil type, although in general, direct soil transfer appeared to most closely approximate source microbiomes. However, irrespective of transfer method, most bacterial sequences in recipient soils were from organisms transferred through all methods. We discuss the merits of each method for controlled soil microbiome studies.