Control of Colletotrichum coccodes on Tomato by Grafting and Soil Amendments

Eight trials were carried out in 2011 and 2012 in Northern Italy to evaluate the efficacy of grafting, compost and biofumigation with Brassica carinata against Colletotrichum coccodes on tomato. Four trials were carried out in commercial farms, and four trials were carried out in plastic tunnels at an experimental centre. The rootstocks ‘Armstrong’, ‘Arnold’, ‘Beaufort’, ‘Big Power’, ‘Brigeor’, ‘Emperador’, ‘King Kong’, ‘Spirit’ and ‘Superpro V295’ were tested. Host plants included several tomato F1 hybrids: ‘Amantino’, ‘Arawak’, ‘CLX 37438’, ‘Cauralina’, ‘CU 8301’, ‘CU 8506’, ‘DRK 7021’, ‘E 34431’, ‘E 50070’, ‘EXP’, ‘Gotico’, ‘Ingrid’, ‘ISI 61401’, ‘ISI 61402’, ‘Profitto’, ‘Punente’, ‘Rugantino’ and ‘Tomahawk’. Tomato roots from the control plots were 34 to 87% diseased in both naturally and artificially infested soil. Among the nineteen commercial tomato hybrids tested, in the presence of a very high disease pressure in a naturally infested soil, ‘Rugantino’ was the least affected by C. coccodes, showing 32% infected roots. ‘Tomahawk’ grafted onto ‘Arnold’, ‘Armstrong’ and ‘Superpro V295’ was significantly less affected by C. coccodes, while ‘Arawak’ grafted onto ‘Armstrong’, ‘Arnold’, ‘Emperador’ and ‘Beaufort’ provided very good control of root rot in the different trials. Compost addition and biofumigation with Brassica pellets were also tested with and without grafting. Soil amendment with compost, in the case of the ‘Arawak’ and ‘Tomahawk’, resulted in a slightly improved disease control only on non‐grafted plants. When grafting and biofumigation were combined in a soil naturally infested with C. coccodes and Meloidogyne arenaria, biofumigation did not improve C. coccodes control in comparison with grafting alone. In a naturally infested soil, compost alone and combined with biofumigation improved disease control only on non‐grafted ‘Tomahawk’ plants. In general, grafting by itself provided very good results in terms of disease control, which were not significantly improved by combination with compost and/or biofumigation.     

The Arabidopsis Myb genes MYR1 and MYR2 are redundant negative regulators of flowering time under decreased light intensity

Changes in the duration, quality and intensity of light affect flowering time. Compared with the effects of light duration and quality, less is known about the effects of light intensity on flowering. Here we describe two paralogous single Myb domain genes, MYB‐RELATED PROTEIN 1 (MYR1) and MYB‐RELATED PROTEIN 2 (MYR2), and their roles as repressors of responses to decreased light intensity in Arabidopsis. Homozygous myr1 myr2 double mutants flowered early under low light intensities. Additionally, myr1 myr2 mutants exhibited increases in petiole length, leaf angle and apical dominance. Genetic analyses involving mutants in the long‐day, gibberellin (GA) and phyB flowering pathways indicated that all aspects of the myr1 myr2 phenotype required GA biosynthesis. The early‐flowering phenotype of myr1 myr2 also required FLOWERING LOCUS T, and myr1 myr2 mutants showed an epistatic interaction with the phyB‐9 mutant. Over‐expression of MYR1 or MYR2 produced GA‐deficiency symptoms that were rescued by application of gibberellic acid (GA₃). Loss of MYR1 and MYR2 function was associated with a twofold increase in GA20ox2 expression and a 30% increase in GA₄ levels, while over‐expression of MYR2 led to a threefold decrease in GA20ox2 expression and a 50% decrease in GA₄ levels. Considered together, these results suggest that the ability of MYR1 and MYR2 to repress flowering and organ elongation is at least partly due to their negative effect on levels of bioactive GA.     

Effect of biofumigation and chemical fumigation on soil microbial community structure and control of pepper Phytophthora blight

Soil biofumigation with brassica plant residues has been shown to significantly suppress soilborne pathogen. However, little published data reported the impact of biofumigation on microbial community structure in pepper (Capsicum annuum L.) production systems under field conditions. Biofumigation with rapeseed (Brassica napus ‘Dwarf Essex’) meal and chemical fumigation with dazomet were tested to control the pepper disease caused by Phytophthora capsici. BF treatment showed the lowest disease incidence among these treatments. Effects on soil bacterial and fungal communities were assessed by denaturating gradient gel electrophoresis and the results showed that the biofumigation increased bacterial diversity and decreased fungal diversity. There was a negative correlation between soil bacterial diversity and disease incidence and a positive correlation between soil fungal diversity and disease incidence. Cloning of the microbial community showed that the microbial community structures were altered by biofumigation. Soil was also evaluated for their chemical properties. Biofumigation increased soil content of total N, NO₃ ^?–N, available P and available K. A significant correlation between soil microbial community structures and soil chemical properties was found. Overall, these results indicated that biofumigation reduced disease incidence of pepper through altering soil microbial community structures.     

Effect of Brassica Biofumigant Amendments on Different Stages of the Life Cycle of Phytophthora cinnamomi

The oomycete plant pathogen Phytophthora cinnamomi causes a highly destructive root rot that affects numerous hosts. Integrated management strategies are needed to control P. cinnamomi in seminatural oak rangelands. We tested how biofumigation affects crucial stages of the pathogen's life cycle in vitro, in infested soils under laboratory conditions and in planta. Different genotypes of three potential biofumigant plant species (Brassica carinata, Brassica juncea, Brassica napus) were collected at different phenological stages, analysed for their glucosinolate contents, and subsequently tested. The most effective genotypes against mycelial growth and sporangial production were further tested on the viability of chlamydospores in artificially infested natural soils and in planta on Lupinus luteus, a host highly susceptible to P.cinnamomi. Brassica carinata and B. juncea genotypes inhibited mycelial growth, decreased sporangial production, and effectively inhibited the viability of chlamydospores in soil, but only B. carinata decreased disease symptoms in plants. Effective genotypes of Brassica had high levels of the glucosinolate sinigrin. Biofumigation with Brassica plants rich in sinigrin has potential to be a suitable tool for control of oak root disease caused by P. cinnamomi in Spanish oak rangeland ecosystems.     

Microsatellite markers for genome analysis in Brassica. I. development in Brassica napus and abundance in Brassicaceae species

One hundred and twenty one microsatellites were identified by screening a λ phage library of Brassica napus. The distribution of these microsatellites within Brassicaceae species was estimated using 81 locus-specific primer pairs. Most of them (83%) amplified fragments either from Brassica oleracea or Brassica campestris, or from both species, whereas less than 30% detected loci in Brassica nigra. The same was true (30–35%) for more-distantly related crucifer species such as Diplotaxis ssp., Brassica tournefortii, Sinapis alba, Raphanus sativus and Eruca sativa. Only 16 microsatellite-specific primer pairs (19.8%) amplified fragments from Arabidopsis thaliana. Moreover, 61 of the primer pairs detecting 198 polymorphisms were used to estimate the extent of genetic diversity among 32 Brassica napus varieties and breeding lines. On average, four alleles per locus were observed. The spring and winter types of oilseed rape could be clearly distinguished by using the microsatellite markers in a cluster analysis. The results demonstrated the high efficiency of these markers for monitoring genetic diversity. Received: 14 April 2000 / Accepted: 3 July 2000     

Trichoderma spp. tolerance to Brassica carinata seed meal for a combined use in biofumigation

Biofumigation by Brassicaceae green manure or seed meal incorporation into soil is an ecological alternative to chemical fumigation against soil-borne pathogens, based on the release of glucosinolate-derived compounds. This study aimed at investigating the tolerance of the beneficial fungus Trichoderma to these compounds in view to combined utilization with Brassica carinata seed meal (BCSM). Forty isolates of Trichoderma spp. were tested in vitro for tolerance to toxic volatiles released by BCSM and in direct contact with the meal. They were found to be generally less sensitive than the assayed pathogens (Pythium ultimum, Rhizoctonia solani, Fusarium oxysporum), even if a fungistatic effect was observed at the highest dose (10 μmole of sinigrin). Most of them also were able to grow on BCSM and over the pathogens tested. A preliminary experiment of integrating BCSM with Trichoderma in soil was carried out under controlled conditions with the patho-system P. ultimum—sugar beet. BCSM incorporation increased pathogen population, but reduced disease incidence, probably due to indirect mechanisms. The greatest effect was achieved when BCSM was applied in combination with Trichoderma, regardless of meal ability to release isothiocyanate. These findings suggest that disease control can be improved by this integrated approach. This study also highlighted that a reduction of allyl-isothiocyanate concentration in soil could occur due to the activity of some Trichoderma isolates. This effect could protect resident or introduced Trichoderma isolates from depressing effects due to the biocidal compounds, but, on the other hand, could reduce the efficacy of biofumigation against target pathogens.     

The dynamic loss and gain of introns during the evolution of the Brassicaceae

Sequence comparison allows the detailed analysis of evolution at the nucleotide and amino acid levels, but much less information is known about the structural evolution of genes, i.e. how the number, length and distribution of introns change over time. We constructed a parsimonious model for the evolutionary rate of intron loss (IL) and intron gain (IG) within the Brassicaceae and found that IL/IG has been highly dynamic, with substantial differences between and even within lineages. The divergence of the Brassicaceae lineages I and II marked a dramatic change in the IL rate, with the common ancestor of lineage I losing introns three times more rapidly than the common ancestor of lineage II. Our data also indicate a subsequent declining trend in the rate of IL, although in Arabidopsis thaliana introns continue to be lost at approximately the ancestral rate. Variations in the rate of IL/IG within lineage II have been even more remarkable. Brassica rapa appears to have lost introns approximately 15 times more rapidly than the common ancestor of B. rapa and Schenkiella parvula, and approximately 25 times more rapidly than its sister species Eutrema salsugineum. Microhomology was detected at the splice sites of several dynamic introns suggesting that the non‐homologous end‐joining and double‐strand break repair is a common pathway underlying IL/IG in these species. We also detected molecular signatures typical of mRNA‐mediated IL, but only in B. rapa.     

Effects of Barium Stress in <i>Brassica juncea</i> and <i>Cakile maritima</i>: The Indicator Role of Some Antioxidant Enzymes and Secondary Metabolites

Soil contamination by toxic trace metal elements, like barium (Ba), may stimulate various undesirable changes in the metabolic activity of plants. The plant responses are fast and with, direct or indirect, generation of reactive oxygen species (ROS). To cope with the stress imposed by the ROS production, plants developed a dual cellular system composed of enzymatic and non-enzymatic players that convert ROS, and their by-products, into stable nontoxic molecules. To assess the Ba stress response of two Brassicaceae species (Brassica juncea, a glycophyte, and Cakile maritime, a halophyte), plants were exposure to different Ba concentrations (0, 100, 200, 300 and 500 μM). The plants response was evaluated through their morphology and development, the determination of plant leaves antioxidant enzymatic activities and by the production of plants secondary metabolites. Results indicated that the two Brassicaceae species have the ability to survive in an environment containing Ba (even at 500 μM). The biomass production of C. maritima was slightly affected whereas an increase in biomass B. juncea was noticed. The stress imposed by Ba activated the antioxidant defense system in the two species, noticed by the changes in the leaves activity of catalase (CAT), ascorbate peroxidase (APX) and guaicol peroxidase (GPX), and of the secondary metabolites, through the production of total phenols and flavonoids. The enzymatic response was not similar within the two plant species: CAT and APX seem to have a more important role against the oxidative stress in C. maritima while in B. juncea is GPX. Overall, total phenols and flavonoids production was more significant in the plants aerial part than in the roots, of the both species. Although the two Brassicaceae species response was different, in both plants catalytic and non-catalytic transformation of ROS occurs, and both were able to overcome the Ba toxicity and prevent the cell damage.     

A rich TILLING resource for studying gene function in <Emphasis Type="Italic">Brassica rapa</Emphasis>

Background  

The Brassicaceae family includes the model plant Arabidopsis thaliana as well as a number of agronomically important species such as oilseed crops (in particular Brassica napus, B. juncea and B. rapa) and vegetables (eg. B. rapa and B. oleracea).     

Biochemical changes induced in seeds of <Emphasis Type="Italic">Brassicaceae</Emphasis> wild species during ageing

The aim of the present study was to determine whether the loss of seed germination capacity and vigour in seeds of four wild Brassicaceae species (Brassica repanda, Moricandia arvensis, Rorippa nasturtium-aquaticum and Sinapis alba) during ageing at 45°C and 90% relative humidity was related to changes in lipid peroxidation and membrane integrity. For all of the species, ageing reduced the final germination percentage and increased the length of time required to reach 50% of final germination (T ₅₀). Large differences in longevity were observed among the species. The times required for viability to be reduced to 80 and 50% of maximum germination (P80 and P50) were the lowest for B. repanda, and these values were two times longer for M. arvensis and R. nasturtium-aquaticum and five times longer for S. alba compared with B. repanda. A loss of seed viability was not associated with malondialdehyde accumulation, suggesting that lipid peroxidation did not cause seed deterioration under these conditions. However, the conductivity test effectively detected seed deterioration in these wild Brassicaceae species, and membrane permeability correlated with both germination and vigour loss. This correlation may provide a valuable mean for early detection of seed viability in wild Brassicaceae species.     

Carbon sequestration in soil in a semi‐natural Miscanthus sinensis grassland and Cryptomeria japonica forest plantation in Aso,Kumamoto, Japan

Although Miscanthus sinensis grasslands (Misc‐GL) and Cryptomeria japonica forest plantations (Cryp‐FP) are proposed bioenergy feedstock systems, their relative capacity to sequester C may be an important factor in determining their potential for sustainable bioenergy production. Therefore, our objective was to quantify changes in soil C sequestration 47 years after a Misc‐GL was converted to a Cryp‐FP. The study was conducted on adjacent Misc‐GL and Cryp‐FP located on Mt. Aso, Kumamoto, Japan. After Cryp‐FP establishment, only the Misc‐GL continued to be managed by annual burning every March. Mass C and N, δ¹³C, and δ¹⁵N at 0–30 cm depth were measured in 5 cm increments. Carbon and N concentrations, C:N ratio, δ¹³C, and δ¹⁵N were measured in litter and/or ash, and rhizomes or roots. Although C input in Misc‐GL by M. sinensis was approximately 36% of that in Cryp‐FP by C. japonica, mean annual soil C sequestration in Misc‐GL (503 kg C ha^?1 yr^?1) was higher than that in Cryp‐FP (284 kg C ha^?1 yr^?1). This was likely the result of larger C input from aboveground litter to soil, C‐quality (C:N ratio and lignin concentration in aboveground litter) and possibly more recalcitrant C (charcoal) inputs by annual burning. The difference in soil δ¹⁵N between sites indicated that organic C with N had greater cycling between heterotrophic microbes and soil and produces more recalcitrant humus in Misc‐GL than in Cryp‐FP. Our data indicate that in terms of soil C sequestration, maintenance of Misc‐GL may be more advantageous than conversion to Cryp‐FP in Aso, Japan.     

Mustard biofumigation disrupts biological control by Steinernema spp. nematodes in the soil

Mustard green manures or seed meal high in glucosinolates, which produce a natural biofumigant upon incorporation into the soil, form an alternative to synthetic fumigants. However, the non-target impacts of these biofumigants in the field are unclear. We examined the effectiveness of soil incorporation of Brassica carinata seed meal both in controlling the plant-parasitic Columbia root-knot nematode (Meloidogyne chitwoodi), and on the biological control exerted by the entomopathogenic nematodes Steinernema feltiae and Steinernema riobrave on root-knot nematodes and the Colorado potato beetle (Leptinotarsa decemlineata). Singly, both the seed meal and Steinernema spp. reduced root-knot nematode damage to potato tubers and increased marketable tuber yields. However, there was a negative interaction between the two bioagents such that their combination did not further improve suppression of plant-parasitic nematodes. Thus, mustard seed meal applications harmful to the target root-knot nematode also disrupted the ability of Steinernema spp. to act as biocontrol agents. Further, we observed modest disruption of the biological control of potato beetles following biofumigation. But, the potato beetles were less likely to lay eggs on potato plants grown in mustard-amended soil, suggesting a counteracting benefit of mustard application. Multiple, complementary controls must be integrated to replace the very effective pest suppression typical of synthetic soil fumigants. Our study suggests significant interference between biofumigation and biocontrol agents in the soil, presenting challenges in combining these two environmentally friendly approaches to managing plant-parasitic nematodes and other pests.     

Crossfit analysis: a novel method to characterize the dynamics of induced plant responses

Background  

Many plant species show induced responses that protect them against exogenous attacks. These responses involve the production of many different bioactive compounds. Plant species belonging to the Brassicaceae family produce defensive glucosinolates, which may greatly influence their favorable nutritional properties for humans. Each responding compound may have its own dynamic profile and metabolic relationships with other compounds. The chemical background of the induced response is therefore highly complex and may therefore not reveal all the properties of the response in any single model.     

First evidence of the occurrence of Turnip mosaic virus in Ukraine and molecular characterization of its isolate

A total of 54 samples of Brassicaceae crops showing symptoms of mosaic, mottling, vein banding and/or leaf deformation were collected in Kyiv region (northern central part of Ukraine) in 2014–2015. A half of collected samples was found to be infected with Turnip mosaic virus (TuMV), and TuMV was detected in samples from Brassica oleracea var. capitata (cabbage), Raphanus sativus, Brassica juncea, Raphanus sp., Sinapis alba, Camelina sativa and Bunias orientalis (weed). The full‐length sequence of the genomic RNA of a Ukrainian isolate (UKR9), which was isolated from cabbage, was determined. Recombination analysis of UKR9 isolate showed that this isolate was an interlineage recombinant of world‐Brassica and Asian‐Brassica/Raphanus phylogenetic groups. This study shows for the first time the occurrence of TuMV in Ukraine.     

Plant Screening for Chromium Phytoremediation

Thirty-six plant species of different agronomic importance, size, dry matter production, and tolerance to heavy metals were evaluated for Cr(III) and Cr(VI) uptake and accumulation as influenced by rate, form, source, and chelate application to a Cr-contaminated soil. There was a significant difference in the degree of tolerance, uptake, and accumulation of Cr among plant species. Sunflower (Helianthus annuus) was the least tolerant to Cr, and Bermudagrass (Cynodon dactylon) and switchgrass (Panicum virgatum) were the most tolerant. Indian mustard (Brassica juncea, cv 426308) and sunflower accumulated more Cr than other agricultural plant species. There was no inhibition of growth and little Cr accumulation in the presence of Cr(III) in soil, but most of the plant species that were treated with Cr(VI) hyperaccumulated Cr and died. EDTA chelate added to soil enhanced Cr(III) accumulation in some plants. The phytoremediation potential of the plant species tested was limited because Cr was accumulated in the plant roots and a high concentration in the shoots was toxic to plants. The difference in behavior between Cr(III) and Cr(VI) and their importance in soil and environment contamination should be the basis for remediation strategies.

     

Increased plant growth and copper uptake of host and non-host plants by metal-resistant and plant growth-promoting endophytic bacteria

The effects of inoculation with two metal-resistant and plant growth-promoting endophytic bacteria (Burkholderia sp. GL12 and Bacillus megaterium JL35) were evaluated on the plant growth and Cu uptake in their host Elsholtzia splendens and non-host Brassica napus plants grown in natural Cu-contaminated soil. The two strains showed a high level of ACC deaminase activities. In pot experiments, inoculation with strain GL12 significantly increased root and above-ground tissue dry weights of both plants, consequently increasing the total Cu uptake of E. splendens and Brassica napus by 132% and 48.2% respectively. Inoculation with strain JL35 was found to significantly increase not only the biomass of B. napus, consequently increasing the total Cu uptake of B. napus by 31.3%, but Cu concentration of E. splendens for above-ground tissues by 318% and roots by 69.7%, consequently increasing the total Cu uptake of E. splendens by 223%. The two strains could colonize the rhizosphere soils and root interiors of both plants. Notably, strain JL35 could colonize the shoot tissues and significantly increase the translocation factors and bioaccumulation factors of E. splendens. These results suggested that Burkholderia sp. GL12 and B. megaterium JL35 were valuable bacterial resource which had the potential in improving the efficiency of Cu phytoextraction by E. splendens and B. napus in a natural Cu-contaminated soil.     

The effect of different host plants on the reproduction and longevity of Nysius natalensis

Nysius natalensis Evans (Hemiptera: Orsillidae) is a pest of sunflower in South Africa. Adults invade sunflower fields from their weedy hosts which occur inside crop fields and on surrounding headlands. The host plant suitability for survival and reproduction as well as the effect of within‐generation host switching was studied on different wild host plants and sunflower. Life history parameters used to assess host plant suitability were F₁ adult survival, pre‐oviposition period, fecundity, and longevity. Nymphs and adults were provided with stems and seeds of five host plants, viz., Amaranthus hybridus L. (Amaranthaceae), Portulaca oleracea L. (Portulacaceae), Chenopodium album L. (Chenopodiaceae), Conyza albida Spreng. (Asteraceae), and sunflower, Helianthus annuus L. (Asteraceae). Nymphs were reared on crushed seed of the five plant species. After completion of the nymphal stage, emerging adults of each host plant group were provided with seed of a different host plant species for food. Adults did not survive long on stems only and very few eggs were laid. Seeds of the host plant species were shown to be an essential source of nutrients for N. natalensis reproduction, whereas the vegetative plant parts were unsuitable. Nymphal food and host‐plant switching between the nymphal and adult stages significantly affected the pre‐oviposition period. Nymphal and adult food source also affected female longevity. The number of eggs laid was not influenced by nymphal food, but was influenced by adult food and the switch between nymphal and adult food. The comparative attractiveness of sunflower and wild host plants for oviposition was also investigated and showed that females preferred to lay eggs on wild host plants, compared with sunflower. These results may explain why N. natalensis will lay their eggs on sunflower after weeds in the vicinity are controlled, or senesce toward the end of the growing season.     

Screening of oilseed rape and other brassicaceous genotypes for susceptibility to Ceutorhynchus pallidactylus (Mrsh.)

Production of oilseed rape, Brassica napus L., is affected by various insect pests. The cabbage stem weevil, Ceutorhynchus pallidactylus (Mrsh.) (Col.: Curculionidae), is one of the most damaging pests in Northern and Central Europe that requires regular control measures. Host plant resistance is a key factor in integrated pest management systems. To evaluate a large number of genotypes for their susceptibility to infestation by C. pallidactylus, new screening techniques were developed for testing both, the amount of feeding and the number of eggs deposited by adult C. pallidactylus on accessions of Brassicaceae under controlled conditions. In no‐choice screening tests, the leaf area consumed by adult cabbage stem weevil was quantified on a wide spectrum of 107 brassicaceous genotypes (B. napus, Brassica rapa L. and Brassica oleracea L. cultivars, breeding lines, resynthesized rapeseed lines and wild Brassicaceae). In comparison to feeding on the standard cultivar ‘Express’, the average leaf area consumed by C. pallidactylus on nine oilseed rape cultivars, four resynthesized rapeseed lines and five other accessions [B. oleracea, Camelina alyssum (Mill.) and Lunaria annua L.] was significantly reduced by 44–90%. In dual‐choice screening tests for the evaluation of oviposition preferences on 42 genotypes, female C. pallidactylus laid significantly fewer eggs into plants of two oilseed rape cultivars, five resynthesized rapeseeds and three accessions of B. oleracea and Brassica fruticulosa Cyrillo, respectively, than into plants of the standard cv ‘Express’. Results of both laboratory screening tests were confirmed by results of additional field testing.     

Trace elements bioavailability to winter wheat (Triticum aestivum L.) grown subsequent to high biomass plants in a greenhouse study

Multielement-contaminated agricultural land requires the adaptation of agronomic practices to meet legal requirements for safe biomass production. The incorporation of bioenergy plants with, at least, moderate phytoextraction capacity into crop rotations with cereals can affect trace elements (TE) phytoavailability and, simultaneously, constitute economic revenues for farmers outside the food or forage sector. Hence, in a crop rotation pot study sunflower (Helianthus annuus L.), modified for high biomass and TE accumulation by chemical mutagenesis, was compared to winter oilseed rape (Brassica napus L.) as pre-crop. On two agricultural soils with different TE loads, the crops´ potential for phytoextraction and for impacts on TE uptake by subsequent winter wheat (Triticum aestivum L.) was studied. The results showed that rape tolerated high-level mixed contamination with metals (Cd, Pb and Zn) and As more than sunflower. In both soils, labile metals concentration increased and soil acidity remained high following sunflower. Furthermore, enhanced grain As accumulation in subsequent wheat was observed. By contrast, soil acidity and Cd or Zn accumulation of subsequent wheat decreased following rape. In the short term, moderate phytoextraction was superimposed by nutrient use or rhizosphere effects of pre-crops, which should be carefully monitored when designing crop rotations for contaminated land.