Journal Article

Shoot tip necrosis of in vitro plant cultures: a reappraisal of possible causes and solutions

Driver, John A., Gulyás, Andrea, Dobránszki, Judit, Landín, Mariana, Hidvégi, Norbert, Teixeira da Silva, Jaime A., Gallego, Pedro Pablo, Mendler-Drienyovszki, Nóra, Márton, László, Nezami-Alanagh, Esmaeil, Wicaksono, Adhityo, Barreal, María E., Magyar-Tábori, Katalin, Kher, Mafatlal M.

2020

Overview

Main conclusion Shoot tip necrosis is a physiological condition that negatively impacts the growth and development of in vitro plant shoot cultures across a wide range of species. Shoot tip necrosis is a physiological condition and disorder that can arise in plantlets or shoots in vitro that results in death of the shoot tip. This condition, which can spread basipetally and affect the emergence of axillary shoots from buds lower down the stem, is due to the cessation of apical dominance. STN can occur at both shoot multiplication and rooting stages. One of the most common factors that cause STN is nutrient deficiency or imbalance. Moreover, the presence or absence of plant growth regulators (auxins or cytokinins) at specific developmental stages may impact STN. The cytokinin to auxin ratio within an in vitro plant can be modified by varying the concentration of cytokinins used in the culture medium. The supply of nutrients to in vitro shoots or plantlets might also affect their hormonal balance, thus modifying the occurrence of STN. High relative humidity within culture vessels and hyperhydricity are associated with STN. An adequate supply of calcium as the divalent cation (Ca 2+ ) can hinder STN by inhibiting the accumulation of phenolic compounds and thus programmed cell death. Moreover, the level of Ca 2+ affects auxin transport and ethylene production, and higher ethylene production, which can occur as a result of high relative humidity in or poor ventilation of the in vitro culture vessel, induces STN. High relative humidity can decrease the mobility of Ca 2+ within a plant, resulting in Ca 2+ deficiency and STN. STN of in vitro shoots or plantlets can be halted or reversed by altering the basal medium, mainly the concentration of Ca 2+ , adjusting the levels of auxins or cytokinins, or modifying culture conditions. This review examines the literature related to STN, seeks to discover the associated factors and relations between them, proposes practical solutions, and attempts to better understand the mechanism(s) underlying this condition in vitro.

• Publisher: Springer Berlin Heidelberg,Springer Nature B.V
• Subject: Agriculture / Antioxidants - chemistry / Antioxidants - pharmacology / Apical dominance / Apoptosis / Auxins / Biomedical and Life Sciences / Boron - metabolism / Boron - pharmacology / calcium / Calcium - metabolism / Calcium - pharmacology / Calcium ions / Calcium transport / cations / Cell culture / Cell Death / culture media / Culture Media - chemistry / Culture Media - pharmacology / Cytokinins / death / Developmental stages / Ecology / Ethylene / ethylene production / Forestry / Genotype / Growth regulators / Humidity / hyperhydricity / Life Sciences / Literature reviews / Multiplication / Necrosis / Nitrogen - metabolism / nutrient deficiencies / Nutrient deficiency / Nutrients / Phenolic compounds / Phenols / Physiology / Plant growth / Plant Growth Regulators - metabolism / Plant Growth Regulators - pharmacology / Plant Sciences / Plant Shoots - cytology / Plant Shoots - drug effects / Plant Shoots - growth & development / Plantlets / programmed cell death / Relative humidity / Review / Rooting / shoot tips / Shoots / Tissue Culture Techniques - methods / Ventilation / Vessels