# Comparison of Biochemical Constituents and Contents in Floral Next of _Castanae_ spp.
## 2 Results
### Correlation between Nectar Characteristics and Meteorological Factors  
As a result of analyzing the Spearman correlation between the properties of nectar and weather conditions, eight correlations were confirmed (Table 2). Temperature and relative humidity were not correlated with nectar volume per catkin. In contrast, temperature showed a strong correlation with nectar concentration (0.772) and free sugar content (0.716), and relative humidity showed a negative correlation with nectar concentration (\(-0.729\)) and free sugar content (\(-0.729\)). The nectar volume per catkin was correlated with nectar concentration (\(-0.631\)), free sugar content (\(-0.681\)), and nectar sugar content per catkin (0.556). Also, the nectar concentration was strongest correlated with free sugar content (0.907).  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Characteristics** & **CCK** & **CCJ** & **CDA** & **CMC** & **CSE** & **H Test \({}^{*}\)** \\ \hline Flowering date & June 19–21 & June 19–21 & June 19–21 & June 19–21 & June 25–27 & June 27–29 & \\ NVC (\(\mu\)L/catkin) & \(20.9\pm 7.6\)\({}^{\text{b}}\) & \(42.7\pm 10.8\)\({}^{\text{a}}\) & \(8.7\pm 2.4\)\({}^{\text{c}}\) & \(11.0\pm 3.0\)\({}^{\text{b}}\) & \(10.7\pm 3.4\)\({}^{\text{b}}\) & \(p=0.000\) \\ NC (Brix) & \(22.8\pm 8.0\)\({}^{\text{c}}\) & \(34.2\pm 12.5\)\({}^{\text{bc}}\) & \(40.3\pm 6.2\)\({}^{\text{b}}\) & \(61.8\pm 5.9\)\({}^{\text{a}}\) & \(43.8\pm 14.6\)\({}^{\text{bc}}\) & \(p=0.000\) \\ FSC (\(\mu\)g/\(\mu\)L) & \(22.6\pm 9.4\)\({}^{\text{c}}\) & \(40.1\pm 14.8\)\({}^{\text{bc}}\) & \(52.3\pm 14.6\)\({}^{\text{b}}\) & \(82.5\pm 16.8\)\({}^{\text{a}}\) & \(56.9\pm 15.2\)\({}^{\text{bc}}\) & \(p=0.000\) \\ Sucrose (\%) & \(3.7\pm 1.2\)\({}^{\text{c}}\) & \(7.9\pm 4.7\)\({}^{\text{b}}\) & \(13.4\pm 1.5\)\({}^{\text{a}}\) & \(15.9\pm 4.9\)\({}^{\text{a}}\) & \(3.2\pm 0.9\)\({}^{\text{c}}\) & \(p=0.000\) \\ Glucose (\%) & \(21.5\pm 1.4\)\({}^{\text{bc}}\) & \(20.5\pm 1.3\)\({}^{\text{c}}\) & \(33.7\pm 0.5\)\({}^{\text{a}}\) & \(22.6\pm 0.5\)\({}^{\text{b}}\) & \(32.7\pm 1.0\)\({}^{\text{a}}\) & \(p=0.000\) \\ Frutcose (\%) & \(74.8\pm 1.9\)\({}^{\text{a}}\) & \(71.7\pm 3.5\)\({}^{\text{b}}\) & \(52.9\pm 1.3\)\({}^{\text{d}}\) & \(61.5\pm 5.4\)\({}^{\text{c}}\) & \(64.1\pm 1.7\)\({}^{\text{c}}\) & \(p=0.000\) \\ S/H ratio & \(0.04\pm 0.02\)\({}^{\text{c}}\) & \(0.13\pm 0.10\)\({}^{\text{b}}\) & \(0.15\pm 0.01\)\({}^{\text{a}}\) & \(0.17\pm 0.06\)\({}^{\text{a}}\) & \(0.02\pm 0.00\)\({}^{\text{c}}\) & \(p=0.000\) \\ SCPC \({}^{1}\) (mg/catkin) & \(0.45\pm 0.2\)\({}^{\text{b}}\) & \(1.35\pm 0.5\)\({}^{\text{a}}\) & \(0.43\pm 0.1\)\({}^{\text{b}}\) & \(0.93\pm 0.4\)\({}^{\text{a}}\) & \(0.31\pm 0.1\)\({}^{\text{b}}\) & \(p=0.000\) \\ \hline \hline \end{tabular} Data represent the mean \(\pm\) SD (\(n=9\)). \({}^{*}\) Kruskal-Wallis H test. The different letters within a row indicate significant differences among _Castanae_ spp. based on Kruskal-Wallis H test with [PERSON]’s multiple comparison tests (\(p<0.05\)). 1 multiply secreted nectar volume (\(\mu\)l/flower) and free sugar content per unit volume (\(\mu\)g/\(\mu\)L). Abbreviations; NVC, nectar volume per catkin (\(\mu\)L/catkin); NC, nectar concentration (Brix); FSC, free sugar content (\(\mu\)g/\(\mu\)L); S/H ratio, sucrose/hexose ratio; SCPC, sugar content per catkin (mg/catkin); CCK, _C. crenata_ (Korean cultivar \(\text{Mipung}\)); CCJ, _C. crenata_ (Japanese cultivar ‘Ungi’); CDA, _C. dentata_ (American chestnut); CMC, _C. mollissina_ (Chinese chestnut); CSE, _C. sativa_ (European chestnut).  
\end{table}
Table 1: Comparison to nectar volume, free sugar content, composition of sugar, and sugar content per catkin in floral nectar of _Castanaea_ spp.