Study on the Photosynthetic Characteristics of Early Flowering Chionanthus retusus Variety ‘Chunxue’

PurposeTo study the photosynthetic characteristics of early flowering Chionanthus retusus ‘Chunxue’ and common C. retusus, providing a theoretical basis for improving variety cultivation and utilization.

MethodTaking the early flowering C. retusus ‘Chunxue’ as the research object, and the common C. retusus growing under the same conditions as the control. The net photosynthetic rate (P_n), intercellular CO₂ concentration (C_i), stomatal conductance (G_s), transpiration rate (T_r) and light response curve of the two C. retusus from May to October were measured by LCpro-SD portable photosynthetic instrument.

ResultsThe P_n of early flowering C. retusus ‘Chunxue’ and common C. retusus reached the maximum value in May and July, with the value of 22.11 and 20.30 μmol/(m²·s), respectively. From May to October, the P_n of early flowering C. retusus ‘Chunxue’ was larger than that of common C. retusus, the P_n of early flowering C. retusus ‘Chunxue’ in August and common C. retusus in July and August showed a bimodal curve, accompanied by photosynthetic lunch break; and the other months were single peak curve. The diurnal variation of C_i of the two C. retusus decreased first and then increased, the diurnal variation of G_s decreased in general, and the diurnal variation of T_r decreased first and then increased and decreased again. The minimum light compensation of early flowering C. retusus ‘Chunxue’ and common C. retusus from May to October were 21.87 and 24.95 μmol/(m²·s), the maximum light saturation points were 1531.22 and 1450.77 μmol/(m²·s), respectively.

ConclusionUnder the same environmental conditions, early flowering C. retusus ‘Chunxue’ has stronger adaptability to light intensity than common C. retusus, and it is more suitable for planting in areas with strong light.