Effect of Azotobacter chroococcum on in vitro pineapple plants’ growth during acclimatization

Abstract

Pineapple is one of the most important tropical fruits, but the availability of planting material is insufficient to agricultural demands. Therefore, several pineapple micropropagation protocols have been developed. However, acclimatization of in vitro plants continues to take a prolonged period. Biofertilizers have been found as safe alternatives to improve the agricultural performances of many crops. This study highlights some of the effects of the application of Azotobacter chroococcum (INIFAT5 strain) on in vitro pineapple plants during acclimatization. The bacteria were sprayed immediately after transplanting to the ex vitro environment; the plants were then sprayed every 4 wk. A control group of plants was established. Subsequently, after 5 mo, the evaluated variables included fresh and dry plant weight, plant height (cm), and root length (cm). The anatomy of middle-aged leaves and roots was also studied: transversal thickness and width of cuticle, epidermis, hypodermis, aquiferous parenchyma, and photosynthetic parenchyma. Thickness of root exoderm, external cortex, internal cortex, and stele were also evaluated. In general, the INIFAT5 strain improved the plant development. Results showed that the bacteria significantly provoked changes in the plant fresh weight, the thickness of the leaf abaxial and adaxial cuticles, and the root exoderm width. Contrastingly, A. chroococcum did not affect the thickness of the leaf photosynthetic parenchyma.

Interrelated effects of mycorrhiza and free‐living nitrogen fixers cascade up to aboveground herbivores

“…González et al. ), making herbivore attacks more difficult or energy consuming. Rhizobia or Pseudomonas colonization may also change volatile emission of plants, affecting the host plant choice of herbivorous beetles (Ballhorn et al.…”

Influence of Watering Solution and Phenotype on the Growth of <i>in Vitro</i> Propagated Pineapple (Smooth Cayenne Cultivar) Plantlets during Acclimatization

“…The plantlets produced in the laboratory request a progressive adaptation to the natural environment. Hence, it is important to search the strategies to improve the acclimatization protocol of pineapple in vitro plantlets [18] [19]. The ultimate stage of acclimatization, which is poorly controlled, can lead to high mortality rates in pineapple [20].…”

Growth of pineapple plantlets during acclimatisation can be monitored through automated image analysis of the canopy

“…The final stage of micropropagation, i.e. acclimatisation, presents a challenge in the case of pineapple since plants grow at a very slow rate during this process, which increases the time needed to release the plants and has associated cost implications (13)(14)(15). Several strategies have been employed to promote faster and more efficient acclimatisation of pineapple plants, including the use of nitrogen-fixing microorganisms (16) and modifications in light supply, irrigation and fertilisation (17)(18)(19).…”