The rhizosphere is the site of organic deposition and the generator of habitat and resource heterogeneity for soil organisms. Plants can modify their rhizosphere through nutrient, moisture and O2 uptake from the rhizosphere, rhizo‐deposition and production of root exudates. As a result, rhizosphere chemical (pH, nutrient solubility, O2, CO2 and other chemicals), physical (moisture and aeration), and biological (soil pathogens, beneficial microorganisms and allelopathy) characteristics will be changed or modified. Rhizosphere microorganisms have positive or negative effects on plant growth and morphology by affecting the plant hormone balance, plant enzymatic activity, nutrient availability and toxicity, and competition with other plants. Plants modify the rhizosphere and as a result will modify the community.

Successful in vitro multiplication of Capparis spinosa was achieved on Murashige and Skoog (MS) medium supplemented with benzyl amino purine (BAP) at 0.8 mg/L. The highest shoot length (35.6 mm) was obtained with the use of 0.4 mg/L BAP and 0.2 mg/L 1-naphthaleneanacetic acid (NAA). Kinetin at 2.0 mg/L produced a multiplication rate of 9.7 microshoots per explants with an average shoot length of 21.3 mm. In vitro rooting was successfully achieved on MS media supplemented with different concentration of indole-3-butyric acid (IBA), indole acetic acid (IAA) or NAA at various concentrations. However, rooting did not occur in the absence of IBA, IAA or NAA. A total of 85% survival was achieved when rooted explants acclimatized ex vitro using a mixture of 1 perlite: 1 peat. In another experiment, in vitro C. spinosa were successfully stored without serious losses by using MS medium supplemented with an appropriate concentration of osmoticum (sucrose, sorbitol, mannitol or glucose) at various concentration (0, 3, 6, 9 or 12%). Two types of plant material were used (in vitro plantlets and in vitro plantlets without tips). The results obtained show that the two type of plant material could be successfully maintained in vitro and optimum treatments were identified for each plant material. Further studies are still needed on medium term conservation to enhance the survival percentages of different plant material type.

Background Tomatoes (Solanum lycopersicon L.) are one of the main daily consumed vegetables in the human diet. Tomato has been classified as moderately sensitive to salinity at most stages of plant development, including seed germination, seedling (vegetative), and reproduction phases. In this study, we evaluated the performance and response of 39 tomato landraces from Jordan under salt stress conditions. Furthermore, the landraces were also genetically characterized using simple sequence repeat (SSR) markers. Results The studied morphological-related traits at the seedling stage were highly varied among landraces of which the landrace number 24 (Jo970) showed the best performance with the highest salt tolerance. The total number of amplification products produced by five primers (LEaat002, LEaat006, LEaat008, LEga003, LEta019) was 346 alleles. Primer LEta 019 produced the highest number of alleles (134) and generated the highest degree of polymorphism (100%) among landraces in addition to primers (LEaat002, LEaat006, LEaat008). The lowest dissimilarity among landraces ranged from 0.04 between accessions 25 (Jo969) and 26 (Jo981) and the highest dissimilarity (1.45) was found between accessions 39 (Jo980) and both 3 (Jo960) and 23 (Jo978). The dendrogram showed two main clusters and separated 30 landraces from the rest 9 landraces. High genetic diversity was detected (0.998) based on the average polymorphism information. Therefore, the used SSRs in the current study provide new insights to reveal the genetic variation among thirty-nine Jordanian tomato landraces. According to functional annotations of the gene-associated SSRs in tomatoes, a few of SSR markers gene-associated markers, for example, LEaat002 and LEaat008 markers are related to MEIS1 Transcription factors genes (Solyc07g007120 and Solyc07g007120.2). The LEaat006 is related to trypsin and protease inhibitor (Kunitz_legume) gene (Solyc03g020010). Also, the SSR LEga003 marker was related to the Carbonic anhydrase gene (Solyc09g010970). Conclusions The genetic variation of tomato landraces could be used for considering salt tolerance improvement in tomato breeding programs.

Salinity is an abiotic stress that reduces the seed germination and productivity of tomatoes. Magnetic treatment has been shown to have a positive effect on the seed germination, seedling growth, and productivity of various crop species. Therefore, three experiments were conducted to evaluate whether treating saline water or seeds with a magnetic field can improve the seed germination and productivity of tomatoes (Solanum lycopersicum) under salinity stress. To evaluate seed germination and seedling growth in response to a magnetic field, two laboratory experiments were carried out by passing four saline water solutions of NaCl (0, 5, 10, and 15 dS/m) through a magnetic field (3.5–136 mT) or exposing tomato seeds to the same magnetic field for 20 min before sowing. In a greenhouse experiment, plants were irrigated with different magnetically-treated and untreated saline water solutions to evaluate plant growth. Magnetic treatment of water or seeds improved seed germination percentage, speed of germination (lower mean time to germination), and seedling length and dry weight in the two laboratory experiments, especially under salinity stress of 5 and 10 dS/m. As the salinity level increased, germination performance and plant growth were significantly decreased. Irrigating tomato plants with magnetically-treated water improved plant height, stem diameter, and fruit yield per plant compared to untreated water, especially under salinity of 0 and 5 dS/m. In conclusion, magnetic treatment of saline water or seeds improved germination performance, plant growth, and fruit yield of tomatoes under saline conditions.

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