Phosphorus ameliorates crop productivity, photosynthesis, nitrate reductase activity and nutrient accumulation in coffee senna (Senna occidentalis L.) under phosphorus-deficient soil

Figures & data

Figure 1.  Structural formula of anthraquinone.

Figure 2.  Effect of five phosphorus levels (P_0, P_1, P_2, P₃ and P₄) on fresh and dry weights per plant, total chlorophyll and carotenoid contents and nitrate reductase activity of coffee senna (Senna occidentalis L.) studied at 120, 270 and 300 DAS (means of three replicates). Duncan's Multiple Range Test (DMRT) was employed to separate the means with letters in the column (p≤0.05).

Table 1 Effect of five phosphorus levels (P_0, P_1, P_2, P₃ and P₄) on yield attributes and seed protein and anthraquinone glycosides contents of coffee senna (Senna occidentalis L.) studied at 330 DAS (means of three replicates).

	Treatments (mg P per kg soil)
Attributes	P0	P1	P2	P3	P4	LSD at 5%
Number of pods per plant	51.2d	54.7c	58.8b	72.3a	73.0a	3.2
Number of seeds per pod	45.0	45.3	45.7	46.0	45.0	NS
100-seed weight (g)	1.84	1.84	1.86	1.87	1.84	NS
Seed yield per plant (g)	39.64d	44.97c	47.08b	53.71a	53.86a	2.05
Seed protein content(%)	30.26d	31.30c	32.21b	34.14a	34.17a	0.831
Total anthraquinone glycosides content (%)	1.34	1.34	1.36	1.37	1.37	NS
Means within a column followed by the same letter are not significantly different (p≤0.05); NS = non-significant.

Figure 3.  Changes in transpiration rate, stomatal conductance and net photosynthetic rate in 270-days old plants of coffee senna (Senna occidentalis L.) subjected to five levels of phosphorus (P₀, P₁, P₂, P₃ and P₄, respectively). Duncan's Multiple Range Test (DMRT) was employed to separate the means with letters in the column (p ≤ 0.05).

Figure 4.  Effect of five phosphorus levels (P_0, P_1, P_2, P₃ and P₄) on leaf-NPK and Ca content of coffee senna (Senna occidentalis L.) studied at 120, 270 and 300 DAS (means of three replicates). Duncan's Multiple Range Test (DMRT) was employed to separate the means with letters in the column (p≤0.05).