Atriplex canescens (Pursh) Nutt. una especie multifuncional de las zonas semiáridas de Norteamérica: una revisión

Atriplex canescens es una especie nativa ampliamente distribuida en las zonas semiáridas de Norteamérica, desde el norte de México hasta el oeste de Estados Unidos de América. La presente revisión de la información publicada sobre esta especie durante los últimos 25 años pretende mostrar su taxonomía, distribución geográfica, hábitat, usos actuales y potenciales, así como las amenazas para su hábitat. Los resultados evidenciaron que el uso más amplio de A. canescens es el forrajero, en la alimentación de ganado bovino, caprino y ovino. También, destacó su empleo en la rehabilitación de suelos degradados, la captura de carbono, la prevención de la erosión y la fitorremediación de suelos contaminados por desechos industriales. Además, tiene un amplio potencial en el campo biotecnológico, como control biológico, biocombustible y fuente de genes tolerantes a la sequía y salinidad; asimismo, el consumo de flores, frutos, hojas y raíces de A. canescens ha sido muy importante para las comunidades indígenas. Sin embargo, a pesar de su amplia distribución enfrenta algunas amenazas, como el cambio de uso de suelo, la competencia con especies invasoras y la reducción de la conectividad entre poblaciones naturales. En síntesis, A. canescens es un taxón con una gran diversidad de usos, por lo que es necesario generar conocimiento para su manejo sustentable y conservación.

Green Remediation And Physiological Responses of Plants To Metal-Contaminated Soils In Jinchang Mining Areas, Western Desert, China

Jinchang mining area, as a metal mine with a long history of arid and semi-arid mining in western China, has brought a great risk of heavy metal pollution to the local environment. In this experiment, tailings, slag and native soil are mixed in equal proportions for the pot experiment settings. 9 species of sand plants unique to the arid region of the western inland were planted to screen the varieties with green remediation value. After six months of plant growth, the concentration of Zn in the plant was the highest, ranging from 103.27 to 467.63mg/kg, followed by Cu, ranging from 25.07 to 200.35mg/kg. In the early stage (2 months), POD was the main defense, and in the later stage (4\6 months), SOD and CAT were the main defense, accompanied by unknown proteins up-regulated. The results of net photosynthetic rate showed that it was inhibited by metal stress in the early stage, and it was high in the late stage to provide material basis for the accumulation and secretion of adaptable and resistant substances. Seven species of plants, such as Suaeda glauca, Bassia scoparia, Halogeton glomeratus, Kalidium foliatum, Medicago falcata, Atriplex canescens, Artemisia desertorum can be used as enrichment materials for Zn and Cu. While, Atriplex canescens has the highest metal enrichment potential, and can be used as a planting variety to enrich Cd, Ni and Pb in a broad spectrum of metals including Zn and Cu. This study lays a solid scientific foundation for green remediation of contaminated soil in arid desert area of western China.

Phenacoccus solenopsis (cotton mealybug).

This mealybug species has the ability to increase rapidly in population size and spread to cover vast areas where host plants occur, in a relatively short period of time. It has been reported from over 200 hosts. Since the original description of P. solenopsis from Atriplex canescens in New Mexico, USA in 1898, no reports on its presence were reported until 1967 (McKenzie, 1967; McDaniel, 1975). Later, Fuchs et al. (1991) reported small, sporadic populations on cotton in Runnels County, Texas, USA in 1988 that spread 75 to 200 miles from the original site with contiguous populations by 1990. With the increase in international trade over the last few decades, this invasive pest has been collected and identified on host material at international ports and in greenhouses outside its native range (Jansen, 2004). As such, P. solenopsis has become established in the Afrotropical, Australasian, Nearctic, Neotropical, and Oriental regions.

Germination and Seedling Growth Responses of Zygophyllum fabago, Salsola kali L. and Atriplex canescens to PEG-Induced Drought Stress

In arid and semi-arid regions, planting drought-tolerant species is the most useful strategy in the reclamation of degraded soils. In the present study, we evaluated the effect of simulated drought by polyethylene glycol (PEG-6000) on seed germination and seedling growth of three desert plants such as Atriplex canescens, Salsola kali and Zygophyllum fabago. Seeds were subjected to water stress to drought stress by PEG at five stress levels (0, −1, −4, −8, −12, −14 bars). Germination of Z. fabago was completely inhibited at an osmotic potential of −8, −10 and −12 bars and the germination of A. canescens was inhibited only at −14 bar. In contrast, S. kali responded positively to high levels of stress and our results showed the highest final germination percent (71.75, 54 and 18.25%) under three-drought stress −8, −12 and −14 bars, respectively. In addition, increasing PEG concentration adversely affected the germination rate and seedling vigor index as well as the root and shoot length of species. Under high stress levels, S. kali achieved a higher germination rate and seedling vigor index compared to Z. fabago and A. canescens. Among species, S. kali was the only one able to develop roots and shoots at −14 bar. Therefore, S. kali could be considered as a promising plant for the rehabilitation of degraded soils at risk of desertification.