کدوی تخم کاغذی

In order to investigate the effect of nitrogen and plant spacing on phenological characteristics, morphology, and fruit yield in pumpkin (Cucurbita pepo L.), an experiment was conducted at the farm of Agriculture Faculty, Azarbaijan Shahid Madani University, during 2013. The study was performed as factorial in a complete randomized block design with three replications. The treatments consisted of nitrogen at five levels (0, 50, 100 and 200 Kg ha-1) and plant spacing with a square array at three levels (30, 60 and 90 cm). According to the results, the planting time until flowering and fruiting was longer in the treatment of 200 kg N. The number of nodes, sub-branches, and leaves per plant was higher in the planting space of 90 cm along with 200 Kg ha-1 nitrogen. The higher plant length and fruit yield were recorded for the planting space of 60 cm along with 150 Kg ha-1 nitrogen. The highest leaf dry weight was related to the 200 Kg ha-1 nitrogen. The use of 150 Kg ha-1 nitrogen caused to the highest number of male and female flowers, fruit fresh weight, number of seeds per fruit. The higher leaf dry weight, male and female flowers, and fruits per plant were obtained in the planting space of 90 cm. Finally, the application of 150 Kg ha-1 nitrogen and planting space of 60 cm led to the highest number of fruits and fruit yield in unit area.

Oilseed pumpkin is an introduced medicinal plant, the seeds as well as some other organs of which are being utilized in treating an array of human diseases in Iran. Considering the plant's significance in the health product's industry on the one hand, and the countrywide drought stresses and a lack of information on mineral nutrition of the oilseed pumpkin, the present study was aimed to study the impact of irrigation regime as well as N application on chlorophyll (Chl) content, gas exchange properties, proline content, yield and yield components of this useful medicinal plant. A 5-replicate split plot, randomized complete block experiment was conducted at the Lavark Research Farm, College of Agriculture, Isfahan University of Technology-Isfahan, Iran in 2009. Three irrigation regimes based on evaporation from a Class-A Standard Evaporation Pan including irrigation after 65 mm (I1=control), 95 mm (I2¬= moderate water deficit) and 130 mm (I3= severe water deficit) were assigned as the main plots. Three nitrogen (N) application rates including zero N (N1= control), 120 N (N2) and 220 N (N3) kg ha-1 of N as urea were chosen as subplots. Leaf Area Index (LAI), gas exchange attributes, Chl and proline content, fruits/plant, seeds/fruit, 1000-seed weight, fruit and seed yields, oil content as well as yield were evaluated. I1¬ and I3 irrigation levels with 2.11 and 1.46 and N3 and N1 nitrogen levels with 2.50 and 1.16 produced the highest and lowest LAI, respectively. Water deficit stress and lowered N application led to significant decreases in leaf Chl content. Water deficit led to decreases in the net photosynthetic rate (A) and leaf stomatal conductance (gs) but it led to increases in internal CO2 concentrations (Ci). While A and gs increased with N application rate, Ci decreased with an increase in N application. Proline content increased with both increases in water deficit stress and N application rate. I3 irrigation level led to 23, 33, 5, 51, 52 and 55 percent decreases in the traits of: fruits/plant, seeds/fruit, 1000-seed weight, seed and fruit yield as well as oil yield, respectively, as compared with the I1 level. N3 level of nitrogen application resulted in 28, 22, 27, 9 and 33 percent decreases in fruits/plant, fruit and seed yield, oil percent as well as oil yield, respectively, as compared with the N1 level. It could be concluded that the negative impact of water deficit stress on yield and its components in oilseed pumpkin is mainly through the decreases in the photosynthetic surfaces, photosynthetic rate and as well as Chl content. Furthermore, application of 220 kg ha-1 of N may lead to increases in LAI, Chl and A, though the latter increases, seemingly, enhance the growth of vegetative organs rather than the reproductive ones and grain yield components.