Ceratozamia aurantiaca, a new cycad species from Oaxaca, Mexico, is described. The endemic to lowland karst tropical rainforests of the northern mountains (Sierra Norte region). This related C. subroseophylla and robusta, together considered part robusta complex due their shared characteristics: robust, upright trunk; large long leaves with densely armed petioles linear subfalcate leaflets; meg...

'Candidatus Liberibacter asiaticus' (CaLas), a non-cultured member of the α-proteobacteria, is the causal agent of citrus Huanglongbing (HLB). Due to the difficulties of in vitro culture, antibodies against CaLas have not been widely used in studies of this pathogen. We have used an anti-OmpA polyclonal antibody based direct tissue blot immunoassay to localize CaLas in different citrus tissues ...

BACKGROUND AND AIMS Some frost-tolerant herbaceous plants droop and wilt during frost events and recover turgor and posture on thawing. It has long been known that when plant tissues freeze, extracellular ice forms. Distributions of ice and water in frost-frozen and recovered petioles of Trifolium repens and Escholschzia californica were visualized. METHODS Petioles of intact plants were cryo...

We report physiological, anatomical and molecular differences in two economically important grapevine (Vitis vinifera L.) cultivars cv. Grenache (near-isohydric) and Chardonnay (anisohydric) in their response to water-stress induced cavitation. The aim of the study was to compare organ vulnerability (petiole and stem) to cavitation by measuring ultrasonic acoustic emissions (UAE) and percent lo...

A simple and reliable protocol for plant regeneration from petioles of micropropagated plants of kiwifruit [Actinidia deliciosa (A. Chev) Liang and Ferguson, var. deliciosa ‘Hayward’] is described. Morphogenic callus was initiated by culturing petioles taken from in vitro-propagated plants. From the media tested, Cheng’s K(h) medium plus 0.1 μM IAA, 4.5 μM zeatin, and 2% sucrose was the best fo...

Nitrate-nitrogen in sugarbeet petioles is used to evaluate current N status of sugarbeet crops. Since the NO,-N changes rapidly during the season, better relationships are needed to interpret these data relative to sugarbeet N nutrition. Sugarbeets (Beta vulgaris, L.) were grown at four N fertilization rates and two irrigation levels to determine the root yield, sucrose percentage, sucrose yiel...

Maize ROUGH SHEATH2 (RS2) and Arabidopsis ASYMMETRIC LEAVES1 (AS1) are orthologous Myb-related genes required for leaf development and act as negative regulators of class 1 KNOTTED1-like homeobox (KNOX) genes in leaf primordia. Expression of RS2 in Arabidopsis fully complements as1 leaf phenotypes and represses the expression of the KNOX gene KNAT1 in leaves. Whereas loss of AS1 function in Ara...