Note: * mean significant different at 0.05 level; ** mean significant
different at 0.01 level.
Correlation Analysis with
Geographic Factors
Meanwhile,
from the results of correlation analysis of oil content and major fatty
acid fractions of A. truncatum seed kernel with geographic
factors (Table 6), it can be seen that the oil content of seed kernel
showed highly significant positive correlation with annual mean
temperature, January mean temperature, July mean temperature and annual
precipitation, and highly significant negative correlation with
altitude, indicating that A. truncatum in the southern plain area
of China, which is at a lower elevation, with higher temperatures and
sufficient precipitation, is more a seed source of high oil content, and
its climatic conditions are are more suitable for the accumulation ofA. truncatum seed oil. Among the saturated fatty acids, both
palmitic acid and stearic acid showed significant positive correlation
with altitude, palmitic acid showed highly significant negative
correlation with January mean temperature and frost-free period, and
stearic acid only showed significant negative correlation with
frost-free period; among the unsaturated fatty acids, eicosapentaenoic
acid showed highly significant positive correlation with altitude, oleic
and linoleic acid showed significant positive correlation with altitude,
and the correlation between saturated fatty acids and unsaturated fatty
acids and altitude was similar, and the content increased with the
increase of altitude. The correlation between saturated fatty acids and
unsaturated fatty acids with altitude was similar, and the content
increased with increasing altitude; α-linolenic acid showed a highly
significant positive correlation with longitude, while eicosapentaenoic
acid and erucic acid showed a strong negative correlation with mean
annual temperature, erucic acid also had a strong negative correlation
with January mean temperature, meanwhile, neuronic acid showed highly
significant negative correlation with mean annual temperature, mean
January temperature, annual precipitation and frost-free period,
indicating that the relative content of neuronic acid was lower in the
seed source with high temperature and sufficient precipitation; and
there was a significant or highly significant negative correlation
between the frost-free period and the main saturated fatty acid
fractions, which indicated that the relative content of fatty acid
fractions of A. truncatum was more in the case of lower
temperature and shorter growing period.
In summary, the oil content of A. truncatum seed kernels was more
affected by latitude, temperature and precipitation, and altitude,
temperature and precipitation were the main reasons for the geographic
variations of fatty acid fractions, and the results of the correlation
analyses also reflected A. truncatum ’s habit of preferring cooler
and wetter temperatures, and being more drought-tolerant.
Table 6. Correlation
analysis between seed kernel oil content, main fatty acid components and
geographical factors of Acer truncatum