Chlorophyll a fluorescence and growth of Neoregelia concentrica (Bromeliaceae) during acclimatization in response to light levels

Abstract

Tissue culturing is widely used for the clonal propagation of several plant species. However, high mortality rates may occur during the acclimatization phase due to the sudden, dramatic changes in light levels. This study evaluated the effect of light level during the acclimatization of Neoregelia concentrica (Vellozo) LB Smith using chlorophyll a fluorescence and growth analysis. N. concentrica plants were multiplied and rooted in vitro on Murashige and Skoog medium and then transferred to plastic trays with individual cells containing vermiculite. The treatments consisted of the ex vitro cultivation of plants under light levels of 30, 50, 70, and full sunlight (100% light) for 28 d. Chlorophyll a fluorescence measurements were taken at 0 (in vitro), 7, 14, 21, and 28 d of acclimatization, and growth trait analyses were made at 28 d. The high irradiance under full sunlight (100% light) induced photoinhibition and reduced the growth rate. Plants grown under partial light (30, 50, and 70%) were less inhibited. A 50% reduction in light level during N. concentrica acclimatization produced rapid plant recovery and higher growth rates than full sunlight.

High Temperature Affects Photosynthetic and Molecular Processes in Field‐Cultivated Vitis vinifera L. × Vitis labrusca L.

“…). M o and δ Ro are not only influenced by high‐temperature stress but can be affected by other factors arising from field cultivation, such as light , salt , or drought . In our experiment, “37°C” and “42°C” stood for pre‐temperature and post high‐temperature treatments, respectively, suggesting that temperature has a significant influence on the photosynthetic and molecular processes in grapevine.…”

Biocontrol Potential of Sclerotinia sclerotiorum and Physiological Changes in Soybean in Response to Butia archeri Palm Rhizobacteria

“…strain BA48R, the characteristics of the initial transient stages were similar to those observed in the pre-pathogen plants, although only the plants treated with B. cereus strain BA88R presented negative post-pathogen amplitude in the O-K stage, which indicates that this strain may have cushioned the damage caused by the pathogen on the photochemical reduction of quinone A (QA). Even so, the negative amplitudes recorded in the O-J and O-I stages indicate that these plants were unable to maintain their capacity to reduce QA photochemically, and thus did not have the kinetic properties necessary for the reduction/oxidation of the pool of plastoquinones [55]. The negative L band recorded in the plants treated with BA88R indicates that the thylakoid membranes were not affected, and were able to maintain the connectivity between the reaction centers of the PSII.…”

“…The negative L band recorded in the plants treated with BA88R indicates that the thylakoid membranes were not affected, and were able to maintain the connectivity between the reaction centers of the PSII. When the L band values are negative, the excitation energy is used more efficiency and the system is more stable [55][56][57].…”

Aclimatização de mudas micropropagadas de genótipos de gérbera

“…As mudas provenientes do cultivo in vitro são de pequeno tamanho (menos de 5 cm) quando transplantadas, de modo que necessitam aumentar entre 10 a 20 vezes o seu tamanho durante a aclimatização, antes de serem transferidas ao viveiro. Além disso, as raízes formadas in vitro podem não ser funcionais quando transplantadas e, sendo assim, novas raízes têm que se desenvolver e se tornar aptas para absorver água do substrato (MARTINS et al, 2015). ZHANG et al (2009) relatam a necessidade da aclimatização das mudas provenientes da micropropagação, pois mudas obtidas in vitro são sensíveis e tenras, uma vez que não desenvolvem a cutícula, resultando em alta transpiração, além da parede celular não apresentar rigidez suficiente para a sustentação, as folhas são delgadas, fotossinteticamente inativas, os estômatos não operam eficientemente, causando, assim, estresse hídrico nos primeiros dias após a retirada das mudas dos frascos.…”