大、小粒型落花生品種之生長特性比較－II、植株全氮與非構造性碳水化合物

Abstract

以小粒型落花生品種臺南選9號與大粒型品種Beni Bunch為材料，分春、秋作於田間進行試驗，始花後每週取樣，測定葉面積與比葉重，分析植株各器官全氮與非構造性碳水化合物(TNC)濃度，以比較兩型品種生理性狀的差異。試驗未能發現單位面積萊果與子粒產量之品種間及期作間差異，但單株產量以大粒型品種較高，葉面積則春作顯著超過秋作，但未能表現於乾物質與子粒生產 ，兩型品種可能具有不同的最適葉面積指數值。Beni Bunch品種營養器官中氮素濃度顯著高於臺南選9號，生育中期以後濃度降低的幅度較大，但種子含氮濃度則較低，顯示大、小粒型品種在氮素需求及利用效率方面的差異。植株愈早分化產生之子房柄的全氮與TNC濃度愈高，暗示同一時間不同生育階段之子房柄間有競爭養分作用存在，因而降低後期發生之子房柄形成成熟萊果的比率，導致落花生生殖效率低落。秋作植株營養器官TNC濃度高於春作，又以乾重超過全株總乾重40%的莖桿而言，TNC濃度以臺南選9號為高，而且Beni Bunch在生育中、後期TNC濃度降低較為明顯，顯示在光合成物供需平衡關係方面，小粒型品種的表現較優，亦可能與大粒型品種子粒充實具有關係。植株營養器官全氮與TNC濃度雖於子粒充實期間降低，但含量均有增加，亦即並無再轉移至子粒之現象發生;萊果壁則具有暫時性貯藏功能，所含養分可再轉移以供子粒充實之需。 The small-seed Spanish variety Tainan S. 9 and large-seed Virginia variety Beni Bunch were grown in the spring and fall crop seasons. Samplings were made after initial blooming for determinations of leaf area, specific leaf weight and concentrations of total N and total nonstructural carbohydrates (TNC) in different plant organs. Experimental results showed no difference in pod and seed yields per ha between varieties between crop seasons. Pod and grain yields per plant were higher for the large- seed Beni Bunch. Leaf area per plant was higher for Beni Bunch and the spring crop than for Taihan S. 9 and the fall crop, respectively. However, the effect of leaf area difference was not reflected on dry matter and grain yields, indicating the two types of varieties might have different optimal leaf area inde under field conditions. N concentrations in vegetative organs of Beni Bunch were consistently higher for Beni Bunch than for Tainan S. 9. Decreases in N concentrations during pod-filling was also significant for toe large-seed variety. These, along with low seed N concentration suggested that N requirement and utilization efficiency of Beni Bunch were different from those of Tainan S.9. Early-developed pegs had higher N and TNC concentrations than the late-developed pegs, indicating possible competition of nutrients between pegs of different maturity degrees. The resulting low reproductive efficiency of peanut plants was therefore suggested. Stem TNC concentration was significantly higher for Tainan S. 9 than for Beni Bunch. Decrease in stem TNC was also significant higher for Beni Bunch during late podfilling. It was hence presumed that in terms of the balance between photosynthetic production and demand, the small-seed variety was superior to the large-seed variety. Although there was a tendency that concentrations of N and TNC decreased in vegetative organs with the advance of plant development, the amount of the two nutrients increased as a result of dry matter increase. This facts showed that there was no net redistribution of N and TNC to the developing grains. Pod wall possessed the function of temporary storage and the stored material could be retranslocated to meet the demand of the developing seeds.