期作間水芋全生育期光合成物質生產之比較

本試驗於1995及1996年分別於本省最適（1月）及較不適宜（7月）之栽種季節下種植水田檳榔心芋，自移植起每月各取樣一次，直到移植後第8個月收穫止，測定水芋生育全期植株各部位的乾物重、全氮與非構造性碳水化合物(TNC)濃度及含量的變化情形，以明瞭期作間產量差異的原因，並探討造成水芋產量降低的主要限制因子。水芋植株各部位在全生育期間皆以葉片的氮素濃度最高，而TNC濃度以球莖為最高，葉柄也具有貯存碳水化合物的功能。l月種植期在地上部生長旺盛期的溫度及日射量較高，故行光合作用的地上部營養器官能提供預貯光合成產物的能力強，同時於球莖快速膨大期轉移至球莖積儲之氮素轉流量較高，地上部可有較多的預貯TNC以供球莖充實，若不考慮呼吸作用之消耗，地上部營養器官TNC最高可貢獻13~19%之球莖TNC，因此收穫產量較高。而7月種植期產量降低的主要原因，為地上部生長旺盛期間的氣溫降低且日射量減少，導致光合成產量不足，同時其轉運分配至球莖的效率低且時間短，故乾物質及碳水化合物不足以提供移植後第6個月以後的球莖快速充實膨大所需，直到收穫止，其球莖乾重、氮素及TNC佔有全株之比例都未有明顯增加。

關鍵字

芋；種植期；乾物質；氮素；非構造性碳水化合物

並列摘要

Corms of wetland taro (Colocasia esculenta (L.) Schott) were planted in the most favorable (January) and less favorable (July) cropping seasons in the year 1995 and 1996 in Taiwan. Plants were randomly samples at one-month interval from planting to harvest (the 8(superscript th) months after planting). Data of dry weight, total nitrogen (N) and total nonstructural carbohydrates (TNC) concentration in different plant fractions was analyzed. The purpose of this study was to understand the causes of yield difference due to seasonal factors and to find out the major limited factors for low yield. It was detected that leaf contained the highest N concentration while corm contained the highest TNC concentration during the whole growth period for both cropping seasons, It was also found that petiole had the capability of storing carbohydrates. The dry weight of corm was higher on January planted plants than July planted plants for both two years. It was assumed that high temperature and high solar radiation during plants vigorous top-growth stage for January planted plants increased the capability of dry matter production in the aboveground vegetative organs along with higher amount of nitrogen transferring to the corm. Similarly, the contribution of TNC to corm bulking was found also high on January planted plants. The maximum possible contribution of total stored TNC to corm TNC at the corm rapid-bulking stage were up to 13~19% on January planted plants when the respiratory consumption was not considered. In conclusion, all the factors for higher photosynthetic production may result in the higher yield on January planted plants. On the other hands, declining temperature, solar radiation and shorter photoperiod caused poor photosynthetic production during vigorous top-growth stage in the aboveground vegetative organs. Therefore the less photosynthetic production transferring to the corm during vigorous top-growth stage may conduct to main cause of lower yield for July planted plants. It was thought that the production of dry matter and carbohydrates during the vigorous growth stage was not enough to meet the demanding for rapid corm bulking since the partition of total dry weight, N and TNC in corm has not significantly increased during the 6th months after planting to the harvest.

並列關鍵字

Taro ； Planting season ； Dry matter ； Nitrogen ； Total nonstructural carbohydrates

國際替代計量

期作間水芋全生育期光合成物質生產之比較

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