Search Results

You are looking at 1 - 4 of 4 items for :

  • Author or Editor: Hening Hu x
  • HortScience x
Clear All Modify Search
Authors: and

The effect of Zn deficiency on reproductive growth of `Stuart' pecan [Carya illinoensis (Wangenh.) C. Koch] was studied. At the most severe Zn-deficiency level, shoots were rosetted and produced neither. staminate nor pistillate inflorescences. At less severe Zn-deficiency levels, catkin length and weight decreased as Zn concentration in the leaf decreased. The number of fruits produced per shoot was reduced by Zn deficiency. Even though fruit abortion was not affected by Zn status of the shoot, fruit death and drying in situ increased with increasing Zn deficiency. Zinc deficiency dramatically suppressed fruit development and resulted in delayed and staggered shuck dehiscence.

Free access
Authors: and

Leaves of `Stuart' pecan [Carya illinoensis (Wangenh.) C. Koch] with various levels of Zn deficiency were analyzed for physiological indicators of leaf vigor. Leaf chlorophyll content, stomatal conductance, and net photosynthesis were adversely affected by Zn deficiency. In leaves with severe Zn deficiency, each of these indicators increased 3- to 5-fold with a doubling of leaf Zn concentration, but stabilized as leaf Zn approached the sufficiency range (14 μg·g-1). High intercellular CO2 associated with low net photosynthesis indicates that stomatal aperture was not the cause of the reduction of net photosynthesis under Zn deficiency.

Free access

Excessive soil and water boron (B) occur widely in California, often in conjunction with high soil salinity. Descriptions of the symptoms of B toxicity and quantification of its impact on Prunus species are not available. In these experiments we describe the impact of high B and saline conditions on uptake, distribution and growth depression in almond, peach, plum and peach/almond hybrid rootstocks

A series of experiments are described that indicate an important additive effect of B on sensitivity of Prunus species to salinity. Boron concentrations in excess of lppm in the irrigation solution, significantly impair plant growth under moderate (non-limiting) salinity conditions and lead to plant death at higher salinity levels. Symptoms of B toxicity in Prunus include stem necrosis and vascular occlusion. Unlike most other species, B does not appear to accumulate in the leaf margins and leaf symptoms are generally not observed. Differences in sensitivity of a range of Prunus species to B toxicity are described.

Initial results suggest that differences in rootstock sensitivity to B and salinity are the result of differential uptkake and partitioning of B, Na and Cl within the plant.

Free access

A 2-year field study was conducted to determine if foliar B applications prior to flowering increased fruit set in olive (Olea europaea L.) cv. Manzanillo. Boron solutions were applied (935 L·ha-1) at four concentrations (0, 246, 491, and 737 mg·L-1) to trees exhibiting no vegetative symptoms of B deficiency. Foliar B application increased both the percentage of perfect flowers and fruit set, but no effect on pollen germination was observed in either year. The increase in fruit set was not accompanied by a reduction in fruit size. The beneficial effects of foliar B application varied between years and were greater when fruit set was low. The results obtained here are in agreement with those observed in other tree species, in which foliar B applications made immediately prior to flowering or during the period of floral bud initiation significantly increased fruit set and yield. The physiological basis for this effect, however, remains unclear.

Free access