Studies on Accumulation and Distribution of Dry Matter,Nitrogen,Phosphorus,and Potassium in Rhizome Lotus(Nelumbo nucifera Gaertn)

Accumulation and distribution of dry matter,nitrogen(N),phosphorus(P),and potassium(K) in rhizome lotus(Nelumbo nucifera Gaertn) were studied by pot experiment for two years.Results showed that,in seeding stages,accumulation of photosynthesis products in leaves was the main growing process.After swollen stem formation,dry matter in leaves,petioles,and rhizomes were distributed to the swollen rhizomes,during which yield formation was the main process.Total dry matter accumulation showed a "slow-quick-stable" changing tendency,and was significantly correlated to the total accumulation of N,P,and K.The ratio of total N,P,and K accumulation in the plant was 1:0.12:1.31.Between 97 d-160 d after transplanting was the key stage for yield formation,during which not only N,P,and K in leaves,petioles and rhizomes were distributed to the swollen rhizomes together with dry matter transport,but also more soil N,P,and K were absorbed by roots and directly transported to the swollen rhizomes.The N,P and K absorbed from soil were 69.8%,79.2%,and 75.0% of the total accumulation rates in the period respectively.At 160 d,the accumulation of dry matter,N,P,and K in the swollen rhizomes contained 81.1%,85.1%,88.8%,and 80.2% of the total accumulation in the lotus plant,respectively.