Paclobutrazol and Its Use in Fruit Production:A Review

There are documentary records referring to paclobutrazol(PBZ)as a growth bioregulator that inhibits the gibberellin synthesis and its application increases yields in fruit and vegetable crop productions.Its agronomic management includes it as an emerging technology to reduce vigour,promote flower induction and flower development in fruit trees with increased economic returns.Its use is banned in some countries because of concerns about residues that can cause harmful effects on the environment.Therefore,the aim of this article was to collect,analyse and summarise relevant information on the use of PBZ in fruit tree production and its possible risks to the environment.The results obtained indicated that the application of PBZ can be effective in solving some problems related to flowering if it is applied in the right amount and at the right time.However,it is necessary to elucidate the physiological processes with which it is associated and its response to be taken into account to increase yield.PBZ is currently used in fruit trees such as mango,lime,apple and guava,increasing their productivity.However,some studies have shown its residual effect on the environment.Therefore,PBZ is a viable strategy,because it presents a series of advantages in the production of fruit trees.However,it is vital to generate protocols that seek its regulation with a rational and sustainable approach.

Pathways of Phosphorus Absorption and Early Signaling between the Mycorrhizal Fungi and Plants

This review highlights the key role that mycorrhizal fungi play in making phosphorus(Pi)more available to plants,including pathways of phosphorus absorption,phosphate transporters and plant-mycorrhizal fungus symbiosis,especially in conditions where the level of inorganic phosphorus(Pi)in the soil is low.Mycorrhizal fungi colonization involves a series of signaling where the plant root exudates strigolactones,while the mycorrhizal fungi release a mixture of chito-oligosaccharides and liposaccharides,that activate the symbiosis process through gene signaling pathways,and contact between the hyphae and the root.Once the symbiosis is established,the extraradical mycelium acts as an extension of the roots and increases the absorption of nutrients,particularly phosphorus by the phosphate transporters.Pi then moves along the hyphae to the plant root/fungus interface.The transfer of Pi occurs in the apoplectic space;in the case of arbuscular mycorrhizal fungi,Pi is discharged from the arbuscular to the plant’s root symplasm,in the membrane that surrounds the arbuscule.Pi is then absorbed through the plant periarbuscular membrane by plant phosphate transporters.Furthermore,plants can acquire Pi from soil as a direct absorption pathway.As a result of this review,several genes that codify for high-affinity Pi transporters were identified.In plants,the main family is Pht1 although it is possible to find others such as Pht2,Pht3,Pho1 and Pho2.As in plants,mycorrhizal fungi have genes belonging to the Pht1 subfamily.In arbuscular mycorrhizal fungi we found L1PT1,GiPT,MtPT1,MtPT2,MtPT4,HvPT8,ZmPht1,TaPTH1.2,GmosPT and LYCes.HcPT1,HcPT2 and BePT have been characterized in ectomycorrhizal fungi.Each gene has a different way of expressing itself.In this review,we present diagrams of the symbiotic relationship between mycorrhizal fungi and the plant.This knowledge allows us to design solutions to regional problems such as food production in soils with low levels of Pi.