Search Results

You are looking at 1 - 10 of 732 items for :

  • Refine by Access: All x
Clear All
Free access

Martin M. Williams II

Yield of all types of corn, including sweet corn, is the result of processes that accumulate plant biomass (the “source”) and processes that allocate plant biomass to the ear (the reproductive “sink”). Yield can be limited by the source or sink

Free access

Ben Hong Wu, Hai Qiang Huang, Pei Ge Fan, Shao Hua Li, and Guo Jie Liu

the source organs, such as by shading leaves, and by treatments affecting the sink organs, such as by removing fruit ( Syvertsen et al., 2003 ). Fruit is the most important assimilate sink in fruit trees. It was reported that the dry matter of fruit

Free access

Marlene Ayala, Lorena Mora, and Joaquín Torreblanca

photoassimilates (mainly carbohydrates; CH 2 O) and nitrogen (N) demands imposed by developing sinks (i.e., buds, flowers, fruits, and leaves). Spur leaves develop rapidly in spring (i.e., 30–40 d after full bloom; DAFB), whereas ES leaves continue growing during

Free access

Rebecca L. Darnell, Nicacio Cruz-Huerta, and Jeffrey G. Williamson

percentage of ovaries that exhibit swelling ( Aloni et al., 1999 ; Polowick and Sawhney, 1985 ) and the extent of ovary swelling ( Cruz-Huerta et al., 2011 ) increase. Increased source-sink ratio also increases the proportion of swollen ovaries. Flower fresh

Free access

Victor N. Njiti, Qun Xia, Leonna S. Tyler, Lakeisha D. Stewart, Antione T. Tenner, Chunquan Zhang, Dovi Alipoe, Franklin Chukwuma, and Ming Gao

importance, including encroachment that can increase harvest cost and reduce harvest efficiency ( Smith and Wright, 1994 ) and increase photoassimilate sink capacity of non-economical (vegetative) plant parts ( Renter and Stassen, 1998 ). Although several

Full access

Thomas E. Marler and Gil N. Cruz

seeds. However, the role of source vs. sink relations could not be determined from this study, and the declines in seed carbohydrates could have been a consequence of declines in whole-tree health and not due to direct seed infestations per se. The seed

Free access

Guohai Xia, Lailiang Cheng, Alan Lakso, and Martin Goffinet

, 2000 ), which further decreases source (leaves) to sink (fruit) ratio. However, large-sized ‘Gala’ fruit is preferred over small fruit at a significant premium on the market. This has prompted growers to strive for large fruit size. Apple fruit size

Open access

Rui Wang, Yuqing Gui, Tiejun Zhao, Masahisa Ishii, Masatake Eguchi, Hui Xu, Tianlai Li, and Yasunaga Iwasaki

sucrose, to sink organs such as young leaves, roots, stems, flowers, and fruits for their utilization. Sucrose is the main sugar that moves through the phloem from leaves (source) to provide soluble carbohydrates to developing flowers (sink). The

Free access

Susanna Marchi, Luca Sebastiani, Riccardo Gucci, and Roberto Tognetti

Net photosynthesis, dark respiration, chlorophyll and carbohydrate content, and leaf and shoot growth of deciduous peach [Prunus persica (L.) Batsch] saplings, grown in greenhouse conditions, were measured to assess changes in carbon balance during leaf development. The 6th, 12th, and 16th leaf node were measured from the first flush at the base through expansion to maturity (the first node being the oldest). Shoot and leaves expanded following a sigmoid pattern in all nodes. The shape of the logistic curve did not vary between the 6th and the 16th leaf node, while the 12th leaf node showed a steeper response, suggesting that the latter reached 50% expansion relatively earlier. Photosynthesis varied with leaf development as young leaves had low CO2 assimilation rates that were reflected in their chlorophyll concentration. Net daily CO2 assimilation was negative in young expanding leaves. The sink-source transition, defined to be the time when the increase in daily carbohydrate exchange rate exceeded the daily increase in leaf carbohydrate content, occurred before full leaf expansion. The transition from import to export was attained 11-12 days after budbreak (corresponding to 41% to 45% of full leaf expansion) for the 6th leaf, about 7-9 days after (38% to 52% of full expansion) for the 12th leaf and after 9-10 days (32% to 38% of full expansion) for the 16th leaf. Below 30% to 50% of full expansion leaves might not respond to assimilate requirements from sinks, being sinks themselves.

Free access

Robyn McConchie and N.Suzanne Lang

A major postharvest problem of Protea neriifolia is premature leaf blackening. Carbohydrate stress, due to floral sink demand, may lead to cellular disorganization and leaf blackening. Leaf blackening, nonstructural carbohydrates, ethylene, carbon exchange rates, stomatal conductance and lipid peroxidation were measured on leaves of vegetative and floral stems preharvest, and during a 7 day dark postharvest period. Postharvest treatments were: 0 or 0.5% sucrose in the vase solution, 20% sucrose pulse, or floral decapitation. Leaf blackening was significantly reduced in vegetative stems and floral stems in the 20% pulse treatment, in comparison to all other treatments. Ethylene production and lipid peroxidation were not associated with leaf blackening in any treatment and leaf respiration rates declined for all treatments over time. The magnitude and rate of leaf blackening was inversely related to leaf starch concentrations, with greatest carbohydrate depletion occurring within 24 h of harvest (by 75-85%). Leaf starch from the 20% pulse treatment increased by 300%, in contrast to declining starch concentrations in all other treatments. The data suggest that the flowerhead functions as the major sink for carbohydrate depletion leading to subsequent leaf blackening.