SUMMARY: Abiotic stress‐induced reactive carbonyl species (RCS) accumulation in plants stimulates oxidative stress by DNA adduct formation, protein carbonylation, and antioxidant pool depletion, triggering senescence or programmed cell death. RCS accumulation under abiotic stress has rarely been studied in halophytic plants that are adapted to highly saline environments. In the current study, exposure to UV‐C irradiation resulted in a higher RCS accumulation in the halophytic Sarcocornia fruticosa ecotypes VM and EL than in Salicornia brachiata (SB) and Arthrocnemum macrostachyum (AM). Accordingly, SB and AM recovered better, whereas VM and EL showed significant damage 14 days after UV‐C application. Reduced aldehyde oxidase (AO) activity, recently shown to detoxify carbonyl aldehydes in Arabidopsis plants, is likely responsible for the significantly higher RCS accumulation and damage in the VM and EL plants. As evidence for this, the VM plants exposed to exogenously applied 3 mM of malondialdehyde or 3 mM of benzaldehyde exhibited decreased AO activity, which resulted in the accumulation of endogenous RCS and severe damage, including mortality. In contrast, the AM plants were able to detoxify RCS by AO activity enhancement, exhibiting recovery after 25 days. These results highlight the role of RCS accumulation in VM and EL plant tissue damage, while improved AO activity, which resulted in improved RCS detoxification in SB and AM, promoted better recovery.

Salinity negatively influences crop growth, but several salt-tolerant plant species (halophytes) are viable crops. Sarcocornia fruticosa (ecotypes EL and VM) is currently cultivated, but there is demand for new crop candidates and higher biomass production. Salicornia brachiata Roxb. and Arthrocneum macrostachyum L. are considered novel crops, and to realize their potential, their response to salinity and nitrogen nutrition was compared to S. fruticosa ecotypes. Experiments revealed that higher N supplemented with lower NaCl significantly increased fresh and dry shoot biomass. Lower biomass was obtained at lower nitrogen supplemented with elevated NaCl, whereas total soluble solids content positively correlated with NaCl fertigation in both Sarcocornia ecotypes. Protein content increased with a lower nitrogen supply. Anthocyanins and oxygen radical absorbance capacity were highest in S. fruticosa EL and A. macrostachyum at higher NaCl supply. The results show that halophytes have a variety of strategies to cope with high NaCl, even between ecotypes of the same species. Notably, repetitive harvesting of S. brachiata delayed flowering enabling year-round biomass production. Additionally, S. brachiata accumulated higher biomass than Sarcocornia VM when grown in a greenhouse at higher radiation than in a growth room and strongly supports its inclusion as a cash-crop halophyte.

In the present scenario, the ever-growing human population, a decreasing availability of land resources and loss of agricultural productivity are the major global concerns, and these possess a challenge for scientific community. To feed the increasing world population, an increase in the crop productivity with available land resources is one of the essential needs. Crop productivity can be increased by engineering the crop plants for tolerance against various environmental stresses and improving the yield attributes, especially photosynthetic efficiency. Nanomaterials have been developed with new functional properties like improved solar energy harvest. With these nanomaterials, nanobionic plants were developed by the facilitated kinetic trapping of nanomaterials within photosynthetic organelle, that is, chloroplast. The trapping of nanomaterials/nanotubes improved chloroplast carbon capture, that is, photosynthesis by improving chloroplast solar energy harnessing and electron transport rate. Besides improving photosynthesis, nanotubes like poly(acrylic acid) nanoceria (PAA-NC) and single-walled nanotube-nanoceria (SWNT-NC) decrease the amount of reactive oxygen species (ROS) inside extracted chloroplast and influence the sensing process in plants, and these are beneficial for a number of physiological processes. The nanobionic approach to engineer plant functions would lead to an era of plant research at the interface of nanotechnology and plant biology. In this chapter, nanobionic approach, transfer of nanomaterial to plants and their offspring and its potential applications to improve photosynthesis will be discussed.