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Adenosine applied daily to the root zone of 'Super Sweet 100' cherry tomato plants (Solanum lycopersicum) in 5 kg of soil mix in 9.5-L plastic pots over a 75-day growing period (3.25 µg/plant) significantly increased total fruit number per plant 1.9- and 2.3-fold and fruit diameter 1.6- and 1.7-fold compared to untreated control plants in two separate experiments, respectively. A single annual foliar application of adenosine (58 g/ha) to 'Fina Sodea' Clementine mandarin (Citrus reticulate) trees in a commercial orchard when fruit were 25 mm in diameter (July, during exponential fruit growth) significantly increased 3-year cumulative yield of fruit of packing carton sizes large (57.2-63.5 mm transverse diameter) and jumbo (63.5-69.9 mm) as both kilograms and number of fruit per tree, without reducing total yield in any year of the study, compared to untreated control trees. The result was a net increase of 5.1 11-kg cartons of commercially valuable large fruit per tree. Two foliar applications of adenosine (58 g/ha) alone, or with triiodobenzoic acid (58 g/ha), to 'Hass' avocado (Persea Americana) trees in a commercial orchard prior to periods of exponential fruit growth in summer (July) and in spring (January) of the high-yield on-crop year resulted in a net increase of 4,424 and 5,750 kg of large size fruit (213-269 g/fruit) per hectare, respectively, with no reduction in total yield in the treatment year or following year compared to untreated control trees. The two treatments increased 2-year cumulative yield of large size fruit by 4,908 and 7,163 kg per ha, respectively. Adenosine has significant potential to increase grower income by increasing fruit size without reducing total yield or fruit quality.

Effect of water stress on Citrus photosynthesis characteristic was studied by using Yamasitaka,Newhall orange,Shatian pomelo as materials.The results showed:chlorophyll content of Citrus is significantly decreased by water stress,there are positive relationship between relative water content of soil and the volume of chlorophyll-a/chlorophyll-b.There are positive relationship between relative water content of soil and net photosynthetic rate(Pn) and transpiration rate,when there is a negative relationship with stoma resistance.Under well water condition,the diurnal variation of net photosynthetic rate of Shatian pomelo,Yamasitaka,and Newhall orange present bimodal curve,but the value and appeared time of peak are different among three varieties.Under water stress,the diurnal variation of Pn of Shatian pomelo show one peak while Yamasitaka,Newhall orange present two peaks.The diurnal variation of Pn of Yamasitaka present bimodal curve,under well water,60%PC and 40%PC treatments.However under 20%PC treatment,Yamasitaka show single curve.

SummaryThe objective of this study was to quantify the effects of high GA3 concentrations applied through trunk injection on the developmental fate of buds of young (glasshouse study) and mature (field study) `Hass' avocado (Persea americana Mill.) trees. The goal of this research was to determine whether a high dose of GA3 could be used to promote vegetative growth, reduce flowering intensity and fruit set and to even out alternate bearing. In both studies, GA3 injections were made at bud swell, prior to bud break. For young trees, injections of 25 or 50 mg GA3 per tree caused precocious inflorescence development and anthesis three weeks earlier than in control trees. GA3 injections did not affect the number of vegetative shoots produced but increased the number of indeterminate inflorescences, at the expense of determinate ones. Increased bud abscission resulting from the GA3 treatments reduced total inflorescence number. Mature trees in a commercial orchard injected with GA3 at 1.0 or 2.5.g per tree on...

Young, fully expanded leaves of 'Hass' avocado on clonal 'Duke 7' rootstock, 2 years from budding, were used to assess changes in leaf NH3-NH4 content. Foliar application of 1.5 g low biuret urea per tree failed to increase the leaf NH3-NH4 content: compare 23.6 ± 5.8 versus 20.1 ± 5.7 μg NH3-NH4 per g fr. wt. leaf tissue (x ± STD. DEV., N = 3 trees per treatment) from trees treated with and without urea, respectively (Nevin and Lovatt, 1989). Foliar application of 1.5 g of low biuret urea per tree to 5-yearold rooted cuttings of the 'Washington' navel orange of comparable size increased the leaf NH3-NH4 content of the trees subjected to 4, 6, or 8 weeks of low temperature 1.7-, 2.2-, and 1.2-fold, respectively.