Boron and calcium homeostasis affects trifoliate rootstock (poncirus trifoliata) root configuration and nutrient utilization

Abstract

One of the most important factors for plant growth is to balance the essential nutrients of a plant. The plant growth, root characteristics and element content of rootstock at different levels of boron (B) and calcium (Ca) were studied in hydroponics to evaluate the interactions between B and Ca in trifoliate rootstock [Poncirus trifoliata (L.) Raf.] through systematic analysis. The results showed that the treatments +B-Ca (10 μM B and 0 mM Ca), -B+Ca (0 μM B with 1.23 mM Ca), -B-Ca (0 μM B and 0 mM Ca) severely inhibited the root length, total root surface area (SA) and the proportion of the middle root (mid-root) of the trifoliate rootstock as compared to +B+Ca (10 μM B with 1.23 mM Ca as CK). The B deficient treatment considerably improved the absorption and utilization of Ca by rootstock. Compared to the control, the biomass of rootstock and B accumulation in -B+Ca or +B-Ca treatments were noticeably decreased. The Fourier-transform infrared analysis (FTIR) analysis demonstrated that Ca promoted B transport to the shoot by the form of B-polyols compounds. It was also observed from the principal component analysis (PCA) that the proportion of the mid-root in the root system might be the main factor for the absorption of the two essential nutrients. In summary, B and Ca absorption exhibited a negative correlation in trifoliate roots.