0000000000043136
AUTHOR
James P. Syvertsen
Leaf starch and nutrient responses to stem girdling and drought stress with respect to understanding HLB (greening) symptoms in citrus
The most important problem in world citrus production is the bacterial disease Huanglongbing (HLB; greening) which is caused by a phloem-limited bacterium that is vectored by a phloem-feeding psyllid. The earliest visible symptoms of HLB in leaves are an asymmetrical chlorosis referred to as "blotchy mottle", thought to be from starch accumulation from a phloem dysfunction and a decline in root health. We tested the hypothesis that such visible symptoms are not unique to HLB by stemgirdling two year-old seedling trees of 'Cleopatra' mandarin and 'Swingle' citrumelo rootstocks in the greenhouse. Girdling induced a 4-fold greater starch concentration in leaves on well-watered trees while star…
Carbohydrate and Nutritional Responses to Stem Girdling and Drought Stress with Respect to Understanding Symptoms of Huanglongbing in Citrus
The most important worldwide problem in citrus production is the bacterial disease Huanglongbing (HLB; citrus greening) caused by a phloem-limited bacterium Candidatus Liberibacter asiaticus. The earliest visible symptoms of HLB on leaves are vein yellowing and an asymmetrical chlorosis referred to as “blotchy mottle,” thought to be the result of starch accumulation. We tested the hypothesis that such visible symptoms are not unique to HLB by stem girdling 2-year-old seedlings of two citrus rootstocks with and without drought stress in the greenhouse. After 31 days, girdling had little effect on shoot growth but girdling increased the relative growth rate of shoots in drought-stressed trees…