Growth， development and photosynthetic characteristics of five Amorphophallus bulbifer varieties （strains）

【Objective】The purpose of the study was to explore the change patterns of growth， photosynthetic efficiency and chlorophyll fluorescence of Amorphophallus bulbifer during different growth periods，and to provide theoretical basis for the selection and breeding of excellent germplasm resources and field production of A. bulbifer.【Method】Five A. bulbifer varieties（strains）（YR00，YR01，YR04，YR09 and GY02）were used as experimental materials to study the growth yield，chlorophyll content，photosynthetic parameters and chlorophyll fluorescence parameters at the head-changing， expansion and maturity stages，as well as yield and glucomannan content at the time of havesting，and indexes were subjected to the principal component analysis and comprehensive evaluation.【Result】The aboveground growth yield of A. bulbifer increased rapidly from the head-changing stage to the expansion stage，and then tended to be stable. Chlorophyll content increased first and then decreased. The net photosynthetic rate（P_n），stomatal conductance（G_s），transpiration rate （T_r） ，actual photosynthetic efficiency［Y（II）］，relative electron transfer rate（ETR）and photochemical quenching coefficient（qL）all showed a decreasing trend，while the variation trends of intercellular CO₂ concentration（C_i）and non-photochemical quenching（NPQ）were different among varieties. Among the five varieties，the aboveground biomass was YR01＞YR09＞YR04＞GY02＞YR00. YR01 and YR04 had lower P_n，Y（II），ETR，qL and higher NPQ in the early growth stage（from the head-changing stage to the maturity stage）to protect their own photosynthetic system from damage，and maintained high photosynthetic capacity to accumulate organic matter in the late growth stage（from the expansion stage to the maturity stage）. YR09 had strong photosynthetic capacity at early growth stage. The final bulb yield was YR01＞ YR09＞GY02＞YR04＞YR00. The glucomannan content was ranked as YR01＞YR04＞YR09＞YR00＞GY02. The comprehensive evaluation showed YR01＞YR09＞YR04＞GY02＞YR00.【Conclusion】There are significant differences in the growth， development and photosynthetic characteristics of different A. bulbifer varieties（strains），among which YR01 and YR09 have high growth yield，yield，glucomannan content and photosynthetic ability，which can be used as excellent germplasm resources for the promotion of A. bulbifer cultivation.