The Effects of Age and Root Formation on the Life‐Span of Excised Cotyledons of Cucurbita pepo

Abstract

Root initiation in Cucurbita cotyledons excised at various ages was studied in nutrient solution and water. The time required for root initiation depends on the age of the cotyledon and on the rooting medium. Nutrient solution favoured root formation. Maximum number of roots, maximal total root length, and maximum life-span were found with cotyledons excised at an age of 14 days. Excision earlier or later resulted in less roots, less total root length, and shorter life-span.

The Effect of Root Formation on the Levels of Protein, Chlorophyll, RNA, DNA and Carbohydrates in Excised Cotyledons of Cucurbita pepo

“…Chlorophyll content of attached cotyledons increased sharply up to 14 days after sowing and then decreased steeply ( Figure 2). The increase coincided with the complete expansion of cotyledons (Mohammad and Al-Mashhadani 1975). In cotyledons excised at 10 and 14 days after sowing, chlorophyll decreased up to 10 days after excision, followed by a gradual increase and reaching a maximum 44 and 52 days after planting, respectively.…”

“…Plants of Cucurbita pepo L. were raised in pots containing compost soil. Cotyledons were excised from the plants at 10, 14, 20 and 24 days after sowing and planted in nutrient solution as previously described (Mohammad and Al-Mashhadani 1975). In excised cotyledons, 10, 14, 20 and 24 days after sowing, root formation occurred 5, 3, 8 and 10 days after planting, respectively.…”

“…However, little information is available concerning the changes in such compounds in excised cotyledons except for mustard cotyledons (Lovell et al 1973). Mohammad and Al-Mashhadani (1975) found that rooting of excised cotyledons of Cucurbita pepo is possible and drastically changes the life-span ofthe organ. In relation to this physiological observation and the general lack of data mentioned above, it was decided to undertake a more detailed study of the changes in fresh weight, dry weight, protein, chlorophyll, RNA, DNA and carbohydrate levels.…”

Effect of root formation on 14C‐glycine uptake and incorporation into protein by attached and excised cotyledons of Helianthus annuus

“…Plants were raised in pots containing compost soil. Cotyledons were excised from the plants at 8, 12 or 20 days after sowing planted in nutrient solution as previously described (Mohammad and Al-Mashhadani 1975). Cotyledons were selected randomly and ten eotyledons were used in each determination.…”

“…Adventitious root formation in leaves and cotyledons delays senscence and extends the life-span of such leaves and cotyledons (Chibnal 1954, Mohammad andAl-Mashhadani 1975). The effect of roots in extending the life-span is probably due to the provision by roots of certain essential requirements for maintaining vigor of leaves and cotyledons (Gregory andSamantaria 1950, Lovelier al.…”