Abstract
Excessive Ca is toxic to plants thus significantly affects plant growth and species distribution in Ca-rich karst areas. To understand how plants survive high Ca soil, laboratory experiments were established to compare the physiological responses and internal Ca distribution in organ, tissue, cell, and intracellular levels under different Ca levels for Lysionotus pauciflorus and Boea hygrometrica, two karst habitant Gesneriaceae species in Southwest China. In the controlled condition, L. pauciflorus could survive as high as 200 mM rhizospheric soluble Ca, attributed to a series of physiological responses and preferential storage that limited Ca accumulation in chloroplasts of palisade cells. In contrast, B. hygrometrica could survive only 20 mM rhizospheric soluble Ca, but accumulated a high level of internal Ca in both palisade and spongy cells without disturbance on photosynthetic activity. By phenotype screening of transgenic plants expressing high Ca-inducible genes from B. hygrometrica, the expression of BhDNAJC2 in A. thaliana was found to enhance plant growth and photosynthesis under high soluble Ca stress. BhDNAJC2 encodes a recently reported heat shock protein (HSP) 40 family DnaJ-domain protein. The Ca-resistant phenotype of BhDNAJC2 highlights the important role of chaperone-mediated protein quality control in Ca tolerance in B. hygrometrica. Taken together, our results revealed that distinctive mechanisms were employed in the two Gesneriaceae karst habitants to cope with a high Ca environment.
Highlights
Crops and vegetables with high Ca contents are potential sources of dietary Ca for human use (Dayod et al, 2010)
For L. pauciflorus and B. hygrometrica, photographic and physiological records were only documented for five concentrations, 2.5, 20, 60, 100, and 200 mmol·L−1, because all leaves of L. pauciflorus dropped when plants were treated with 350–900 mmol·L−1 Ca(NO3)2 and no leaf was available for physiological measurement
To investigate the capacity of karst plants to survive high Ca environment, plants and rhizospheric soils of 10 species that were commonly found in Southwest China karst areas, including 3 ferns (C. fortunei, P. multifida and S. moellendorffii), 2 grasses (E. comosum and O. undulatifolius), and 5 dicots (C. tomentosa, E. adenophorum and three species of Gesneriaceae, e.g., B. hygrometrica, L. pauciflorus, and P. rufescens), were collected from their natural habitats and determined for total Ca contents
Summary
Crops and vegetables with high Ca contents are potential sources of dietary Ca for human use (Dayod et al, 2010). The progress has been limited, essentially because that excessive intracellular calcium causes toxicity to plants. Though Ca is an essential macronutrient for plants with key structural and signaling roles (Dayod et al, 2010; Gilliham et al, 2011), excessive intracellular Ca can precipitate with phosphates, prevent seed germination, disturb photosynthesis, reduce growth rate and form tiny yellowish or gold spots of fruits (Chan et al, 2003; White and Broadley, 2003). Finding a way to control plants Ca and accumulation without disturbing normal growth and survival under high Ca condition is a key step for generation of plants with high Ca contents
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
