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Experiments were carried out to evaluate the effect of seed treatment on germination of Cuscuta campestris. This may provide the possible ways to overcome the problem of dormancy in Cuscuta campestris. The experiments were conducted in the Laboratory of Crop Production and Horticulture, Modibbo Adama University of Technology, Yola, Adamawa State, Nigeria, using mechanical scarification and tetraoxosulphate (VI) acid (H2SO4). For the mechanical scarification the treatments were unscarified, scarified using sandpaper and scarified using gravel arranged in a completely randomized design (CRD) and replicated four times. For the tetraoxosulphate (VI) acid (H2SO4) scarification, the treatment of control, 9:1, 7:3, 1:1, 4:6, 3:7, 2:8 and 1:9 H2SO4 were laid out in a Split plot design and replicated three times. The mechanical scarification was not significant (P ≤ 0.05), a rapid increase of germination from day 3 to day 9 was observed, and the highest rate of germination percentage (14% - 22%) obtained on day 9. Tetraoxosulphate (VI) acid treatment of 4:6 concentrations significantly gave the highest C. campestris seeds germination percentage (40.07%) compared with the rest of the treatments, while the time of soaking the seeds in the tetraoxosulphate (VI) acid showed that soaking the seeds for 1 minute significantly gave the highest percentage germination (39.98%) of C. campestris compared with the 3 and 5 minutes soaking treatments. It can be concluded that sulphuric acid of 4:6 concentrations treatments has the potentiality to break dormancy of C. campestris seeds.

Dodders (Cuscuta spp. Family: Cuscutaceae) are distributed worldwide [

Germination is generally low and poor in annual holoparasites such as Cuscuta. Germination increases by scarification of seeds of many Cuscuta species [_{2}SO_{4}; while [

Two different experiments were conducted in the Laboratory of the Department of Crop Production and Horticulture, Modibbo Adama University of Technology, Yola, Adamawa State, Nigeria. These experiments were on mechanical scarification and concentrated tetraoxosulphate (VI) acid (H_{2}SO_{4}). Mechanical scarification was achieved by subjecting Cuscuta campestris seeds to only three methods of scarification as follows: unscarified, scarified using sandpaper and scarified using small sand gravels of an average of 4.4 mm in diameter. Sandpaper scarification was achieved in the following manner as described by Hutchison and Ashton (1979). Rubber paddles was attached to the shaft of a Virtus 45 hamogenizer from which the blades had been removed. Paddles were cut from rubber and attached to the shaft with epoxy cement. The shaft was inserted into a plastic jar line with sandpaper. Seeds were added and spun by the paddle. Small sand gravels were used by taking dried seeds and placed in metal container with gravels. The container was shaken vigorously for 3 to 5 minutes to enable the gravels cause abrase of the seed epicarp. The seeds were taken out of the gravel, dusted and then placed in Petri- dishes with laden Whatman filter papers (9.0 cm). One hundred and sixty seeds were placed in each of a set of ten Petri-dishes. The treatments were arranged in a completely randomized design (CRD) and replicated four times. Distilled water was added at 24 hour intervals and germination of the seeds was observed and recorded. Tetraoxosulphate (VI) acid (H_{2}SO_{4}) was used at different concentrations as treatments for 1, 3 and 5 minutes as follows: 1 mol H_{2}SO_{4} (90%), 3 mol H_{2}SO_{4} (70%), 5 mol H_{2}SO_{4} (50%), 6 mol H_{2}SO_{4} (40%), 7 mol H_{2}SO_{4} (30%), 8 mol H_{2}SO_{4} (20%) and 9 mol H_{2}SO_{4} (10%) with distilled water as the control. One hundred and sixty eight seeds of Cuscuta were taken and immersed in concentrated grade H_{2}SO_{4} in a conical flask for 1 minute [_{2}SO_{4} as the subplot effect.

Data were collected on germination percentage (%) of Cuscuta. Cuscuta campestris that germinated days after placing on Petri-dish were observed at an interval of 3 days for 2 weeks. Data collected were analyzed using analysis of variance (ANOVA) as described by [

_{2}SO

_{4}) and Soaking Time on Germination of Cuscuta campestris

The effects of tetraoxosulphate (VI) acid, soaking time and the interaction between tetraoxosulphate (VI) acid and soaking time on the germination of C. campestris seed was significant on day 3, 6, 9 and the combined mean for Trials I and II with the exception of day 6 in the Trial II and soaking time in the Trial I of day 6, Trial II of day 3, 6, 9 and the combined mean of day 3 (

Germination percentage (%) | |||||||||
---|---|---|---|---|---|---|---|---|---|

Day 3 | Day 6 | Day 9 | |||||||

Treatment | Trial I | Trial II | Mean | Trial I | Trial II | Mean | Trial I | Trial II | Mean |

Tetraoxosulphate (VI) Acid(TOS) | |||||||||

Control | 3.51^{a1} | 1.13^{ab} | 2.32^{a} | 4.70^{a} | 1.32^{a} | 3.01^{a} | 75.99^{a} | 3.65^{a} | 39.82^{a} |

9:1 H_{2}SO_{4} | 0.33^{c} | 0.40^{b} | 0.36^{c} | 0.46^{e} | 0.73^{a} | 0.60^{d} | 57.14^{c} | 0.99^{b} | 28.07^{c} |

7:3 H_{2}SO_{4} | 0.47^{c} | 0.99^{ab} | 0.73^{c} | 0.73^{e} | 0.86^{a} | 0.80^{cd} | 74.40^{a-c} | 1.06^{ b} | 37.73^{ab} |

1:1 H_{2}SO_{4} | 0.40^{c} | 1.39^{a} | 0.90^{bc} | 0.60^{e} | 0.93^{a} | 0.76^{d} | 72.55^{a-c} | 0.79^{ b} | 36.67^{a-c} |

4:6 H_{2}SO_{4} | 1.79^{b} | 0.93^{ab} | 1.36^{b} | 2.58^{b} | 0.93^{a} | 1.75^{b} | 78.68^{a} | 5.62^{a} | 40.07^{a} |

3:7 H_{2}SO_{4} | 0.79^{c} | 0.79^{ab} | 0.79^{c} | 1.92^{bc} | 0.73^{a} | 1.33^{bc} | 67.19^{a}^{-}^{c} | 1.59^{ b} | 34.39^{a-c} |

2:8 H_{2}SO_{4} | 0.66^{c} | 0.66^{ab} | 0.66^{c} | 0.99^{de} | 0.66^{a} | 0.83^{cd} | 66.73^{a-c} | 0.80^{b} | 33.76^{a-c} |

1:9 H_{2}SO_{4} | 0.53^{c} | 0.66^{ab} | 0.60^{c} | 1.66^{cd} | 1.19^{a} | 1.42^{b} | 59.86^{bc} | 2.32^{ab} | 31.09^{bc} |

SE (±) | 0.23 | 0.34 | 0.22 | 0.24 | 0.34 | 0.22 | 4.66 | 0.80 | 3.32 |

Soaking time (T) | |||||||||

1 minute | 1.61^{a} | 0.67^{a} | 1.14^{a} | 2.58^{a} | 0.87^{ab} | 1.73^{a} | 78.26^{a} | 1.69^{a} | 39.98^{a} |

3 minutes | 0.60^{b} | 1.22^{a} | 0.91^{a} | 1.12^{b} | 1.22^{a} | 1.17^{a} | 64.12^{a} | 1.79^{a} | 32.95^{b} |

5 minutes | 0.97^{ab} | 0.72^{a} | 0.85^{a} | 1.42^{b} | 0.67^{ b} | 1.04^{b} | 64.83^{a} | 1.27^{a} | 33.05^{b} |

SE (±) | 0.38 | 0.55 | 0.36 | 0.39 | 0.55 | 0.36 | 7.62 | 2.28 | 3.00 |

Interaction (TOSXT) | ^{*2} | Ns | Ns | ^{* } | Ns | ^{* } | Ns | Ns | ^{* } |

^{1}Means in the same column followed by the same letter(s) are not significantly different from each other according to Duncun’s Multiple Range Test (DMRT) at 5% level of probability. ^{*}Significantly different at 5% level of probability. NS = not significantly different at 5% level of probability.

treatments significantly had the lowest percentage germination of C. campestris seeds compared with the control (3.51%), while in Trial II, 1:1 H_{2}SO_{4} treatment significantly had higher germination percentage of 1.39 C. campestris seeds which were at par with all the other treatments except 9:1 H_{2}SO_{4} treatment (_{2}SO_{4} and control treatment significantly gave the highest germination percentage of 78.68 and 75.99 Cuscuta seeds than the 9:1 H_{2}SO_{4} and 1:9 H_{2}SO_{4} treatment, but was comparable with the rest of the tetraoxosulphate (VI) acid treatments (_{2}SO_{4} treatments recorded the highest germination percentage of 3.65% and 5.62% C. campestris seeds respectively, which were at par with 1:9 H_{2}SO_{4} treatment. The combined mean for both trials similarly, showed that the 4:6 H_{2}SO_{4} and the control recorded significantly higher germination percentage of 40.07 and 39.82, respectively C. campestris seeds when compared to the 9:1 H_{2}SO_{4} and 1:9 H_{2}SO_{4} treatments but were at par with the other H_{2}SO_{4} treatments (

The soaking time revealed that in Trial I on day 3 and 6 the 1 minute soaking treatment significantly had the highest germination of C. campestris seeds than the 3 and 5 minutes soaking treatments (

The interaction between tetraoxosulphate (VI) acid treatments and the soaking time was significant on C. campestris seeds germination only at day 3 and 6 of Trials I, though for the combined only on day 6 and 9 significance were only observed (

The interaction between tetraoxosulphate (VI) acid and soaking time showed that the germination of Cuscuta campestris seeds was significantly affected in Trial I on day 3 (_{2}SO_{4} treatments and soaking time had significantly the lowest germination of C. campestris seeds compared with the control treatment (

Germination of Cuscuta campestris seeds were significantly affected by the interaction between tetraoxosulphate (VI) acid and soaking time in Trial I on day 6 (

Similarly, the 4:6 and 3:7 H_{2}SO_{4} treatments at 1 minute soaking time had the highest germination of Cuscuta seeds compared with the rest of the interaction treatments (

Treatment | Soaking time (minutes) | ||
---|---|---|---|

1 | 3 | 5 | |

Control | 4.76^{a} | 2.38^{cd} | 3.37^{b} |

9:1 H_{2}SO_{4} | 0.40^{g-j} | 0.00^{h-j} | 0.60^{f-j} |

7:3 H_{2}SO_{4} | 0.80^{e-g} | 0.20^{g-j} | 0.40^{g-j} |

1:1 H_{2}SO_{4} | 0.40^{g-j} | 0.80^{e-g} | 0.00^{h-j} |

4:6 H_{2}SO_{4} | 2.98^{bc} | 0.40^{g-j} | 1.99^{c-e} |

3:7 H_{2}SO_{4} | 1.59^{d-f} | 0.40^{g-j} | 0.40^{g-j} |

2:8 H_{2}SO_{4} | 0.80^{e-g} | 0.20^{g-j} | 0.99^{e-g} |

1:9 H_{2}SO_{4} | 1.19^{e-g} | 0.40^{g-j} | 0.00^{h-j } |

SE (±) 0.38 |

Treatment | Soaking time (minutes) | ||
---|---|---|---|

1 | 3 | 5 | |

Control | 5.75^{a} | 4.56^{b} | 3.77^{b} |

9:1 H_{2}SO_{4} | 0.80^{def} | 0.00^{ef} | 0.60^{d-f} |

7:3 H_{2}SO_{4} | 1.59^{cd} | 0.20^{d-f} | 2.58^{c} |

1:1 H_{2}SO_{4} | 0.60^{d-f} | 0.99^{de} | 0.20^{d-f} |

4:6 H_{2}SO_{4} | 3.97^{b} | 0.99^{de} | 2.78^{c} |

3:7 H_{2}SO_{4} | 3.97^{b} | 0.79^{d-f} | 1.00^{de} |

2:8 H_{2}SO_{4} | 1.59^{cd} | 0.40^{d-f} | 0.99^{de} |

1:9 H_{2}SO_{4} | 2.38^{c} | 1.00^{ de} | 1.59^{cd} |

SE (±) 0.46 |

exception of 4:6 H_{2}SO_{4} and 3:7 H_{2}SO_{4} treatment at 1 minute soaking time compared with the control treatment which gave the highest germination (

On day 9, the germination of C. campestris seeds was significantly affected by the interaction between tetraoxosulphate (VI) acid and soaking time of the combined mean of Trials I and II (_{2}SO_{4}, 1:1 H_{2}SO_{4} and 4:6 H_{2}SO_{4} at 1 minute soaking time (

Mechanically scarified seed with sandpaper continuously gave higher germination percentage of the combined mean followed by gravel and the least from the unscarified seeds (control) though not significant. Probably, this showed that C. campestris seeds were more scarified with sandpaper than the rest of the mechanical treatments which had less potential of breaking the dormancy of the seed. Similarly, [

Treatment | Soaking time (minutes) | ||
---|---|---|---|

1 | 3 | 5 | |

Control | 3.37^{a} | 3.28^{a} | 2.38^{b} |

9:1 H_{2}SO_{4} | 0.70^{d-g} | 0.60^{d-g} | 0.50^{d-g} |

7:3 H_{2}SO_{4} | 1.39^{c-e} | 0.60^{d-g} | 0.40^{d-g} |

1:1 H_{2}SO_{4} | 0.60^{d-g} | 1.19^{c-f} | 0.50^{d-g} |

4:6 H_{2}SO_{4} | 2.38^{b} | 1.39^{c-e} | 1.49^{cd} |

3:7 H_{2}SO_{4} | 2.38^{b} | 0.70^{d-g} | 0.90^{c-g} |

2:8 H_{2}SO_{4} | 1.10^{c-g} | 0.40^{d-g} | 0.99^{c-g} |

1:9 H_{2}SO_{4} | 1.89^{bc} | 1.19^{c-f} | 1.19^{c-f} |

SE (±) 0.36 |

Treatment | Soaking Time (minutes) | ||
---|---|---|---|

1 | 3 | 5 | |

Control | 45.34^{a} | 37.70^{bc} | 36.42^{bc} |

9:1 H_{2}SO_{4} | 38.39^{b} | 23.12^{f} | 25.80^{ef} |

7:3 H_{2}SO_{4} | 44.74^{a} | 32.14^{cd} | 36.31^{bc} |

1:1 H_{2}SO_{4} | 43.35^{a} | 36.51^{bc} | 30.16^{de} |

4:6 H_{2}SO_{4} | 44.91^{a} | 37.40^{bc} | 37.90^{b} |

3:7 H_{2}SO_{4} | 30.56^{de} | 39.09^{b} | 33.53^{cd} |

2:8 H_{2}SO_{4} | 37.70^{bc} | 26.99^{e} | 36.61^{bc} |

1:9 H_{2}SO_{4} | 34.82^{ce} | 30.77^{d} | 27.68^{e} |

SE (±) 3.00 |

At the end of the trials combined means showed that tetraoxosulphate (VI) acid treatment of 4:6 concentration significantly gave the highest C. campestris seeds germination compared with the control and the rest of the treatments. Combined mean for the time of soaking the seeds in tetraoxosulphate (VI) acid revealed that the seeds soaked for 1 minute had the highest germination of C. campestris compared with the 3 and 5 minutes treatments. This indicates that the longer the soaking time the seed coat is ruptured the faster rate of germination, however, prolonged immersion may be injurious to the seeds as the acid may rapture vital parts of the embryo. This is in line with the findings of [_{2}SO_{4}) for 3 minutes gave the highest germination of 50%, but none of the seeds germinated after soaking for 5 minutes.

It can be concluded that tetraoxosulphate (VI) acid of 4:6 concentrations treatments has the potentiality to break dormancy of C. campestris seeds to germinate.

A. B. Mustapha,N. A. Gworgwor,B. B. Jakusko, (2015) Effect of Mechanical and Chemical Scarification on Germination of Dodder (Cuscuta campestris Yunck.) Seed. World Journal of Engineering and Technology,03,31-36. doi: 10.4236/wjet.2015.33B006