Abstract
Low soil moisture and N in the fynbos are a major constraint to plant growth and N2 fixation in legumes, including Aspalathus species. The 15N and 13C natural abundance techniques were used to study N nutrition and plant water relations in different Aspalathus species sampled from 13 study sites in the fynbos. The results showed that A. acuminata shoots recorded lower δ15N values at Kalbaskraal, Worcester Langerug and Roundebosch, resulting in higher %Ndfa at those sites relative to Elim, which registered greater δ15N values. However, A. hispida shoots showed the lowest δ15N at Elim and Dutoitskloof than Yzerfontein, and Silwerstroomstrand, resulting in high %Ndfa at Elim. Of A. cordata, A. astroites, A. hispida, and A. wildenowiana collected from Dutoitskloof differed in δ15N and %Ndfa. A. cordata and A. astroites shoots showed lower δ15N, leading to higher %Ndfa than A. wildenowiana, which exhibited greater shoot δ15N. Of four Aspalathus species (A. cordata, A. carnosa, A. capensis and A. juniperina) sampled from Silvermine, A. cordata revealed the lowest δ15N and hence the highest %Ndfa. Conversely, A. carnosa recorded the highest shoot δ15N and the lowest %Ndfa. At Kokrivier, shoot δ15N was much greater in A. zeyheri and lowest in A. incurvifolia, resulting in higher %Ndfa in the latter than the former. The Aspalathus species differed in water-use efficiency or shoot δ13C values, which ranged from −30.35‰ to −26.93‰. Rainfall, soil moisture deficit and altitude were the major determinants of shoot δ13C values, but how these factors influence shoot δ13C of plants remains to be determined.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: 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.