Non-flowering Shoots Research Articles

The resource balance of Milium effusum with emphasis on environmental resource supply.

Growth of the broad-leaved graminoid Milium effusum, occurring in shady deciduous forests, was matched with periods of high light influx through the tree canopy in spring and autumn. Fertile shoots grew faster than sterile shoots. Leaves on flowering shoots were fully developed when the budbreak started on the trees, whereas nonflowering shoots had fully developed leaves when the tree canopy closed. Leaf concentrations of N and P were high (6.1 and 0.74% respectively) in spring but decreased as the leaves expanded. Maximum pool sizes of N and P in whole tillers were reached about one month after the onset of spring growth, whereas maximum spring pools of K, Mg, and Ca were timed with peak biomass about one month later. The leaves lost nutrients during summer when no growth took place. Since leaching losses were negligible, nutrients were probably allocated from the leaves to support root growth. Autumn reallocation to winter stores was low. The pattern of growth and nutrient use suggests that light availability, i.e., the resource in relatively lowest supply, regulates the investment of the resource in highest supply, i.e., nutrients. This is consistent with previously reported observations on Eriophorum vaginatum, a graminoid of low nutrient - high light environments. This species utilizes nutrients efficiently at the expense of less efficient acquisition of carbon. We suggest that selection for efficient utilization of the resource in lowest relative supply has been a strong driving force behind the physiological adaptation of both species to their environments.

Kiwifruit: Effects of thinning on fruit size, vegetative growth, and return bloom

Abstract On well pollinated kiwifruit vines (Actinidia deliciosa (A. Chev.) C. F. Liang et A. R. Ferguson var. deliciosa cv. Hayward) a reduction in fruit numbers by flower thinning increased mean fruit weight. Thinning reduced total yield and yield of fruit in the preferred export sizes (i.e., fruit weight >90 g). Reducing fruit numbers to less than 330 per metre of T-bar row increased yield of fruit in the two large size grades only (> 132 g). Flower production was less on vines that had a high crop load the previous season. This reduction was primarily because of fewer flowers per flowering shoot. Percentage bud break and the proportion of non-flowering shoots were not affected. Up to threefold differences in fruit numbers per vine were produced by the thinning treatments but this did not significantly affect vegetative growth or the soluble solids content of fruit near harvest.

Graft-induced off-season flowering and fruiting in the mango (Mangifera indicaL.)

SummaryOff-season, summer flowering and winter fruiting was induced in mango cvs Dashehari and Totapari, which normally do not flower out of season, when their defoliated shoots were grafted onto the shoots of the off-season cv Royal Special. Graft transmission of the flowering stimulus was possible from March to the first week of May, which is the period when the donor shoots of Royal Special are themselves capable of flowering, after which only vegetative shoots emerged from the receptor scions and donor stocks. When defoliated scion shoots of cv Royal Special were grafted onto non-flowering shoots of cvs Dashehari and Totapari the scion failed to flower. Fruit set and development were markedly influenced by temperature. Most fruits were harvested from the May-grafted shoots, probably due to moderate temperatures during July and August. Very high temperatures from April to June were very detrimental to March- and April-graft-induced panicles. The quality of mature graft-induced off-season fruits was exc...

Increasing growing points and oil yields in lavender by growth regulator sprays

Immature plants ofLavandula angustifolia x L. latifolia (cv. Twickle Purple) were sprayed with Atrinal and P293 when the growing shoots bore four to six expanded leaves. Atrinal increased the number of inflorescences per plant by stimulating otherwise dormant axillary buds on the shoots of the current season. The number of nonflowering shoots arising on older wood was also increased. The number of florets and the fresh weight per inflorescence were reduced, but the number of florets per plant was increased overall. Oil content per plant was doubled without altering oil composition or floret structure. Flower stalks were shortened below and between the floral nodes. Atrinal sprays achieved a machine-harvestable canopy in 3-year-old plants. Untreated plants required a full year longer to develop similar canopies. P293 and manual disbudding were not as effective as Atrinal. It is suggested that such spray treatments have a useful potential in reducing the time required for the development of the mature canopy form, and so obtaining earlier financial returns on establishment costs.

The effect of duration of cold treatment on growth and flowering of liatris

Dry corms of Liatris spicata L. ‘Gloriosa’ (gay-feather) were stored at 3–5°C for 12, 10, 8, 6, 4 or 2 weeks, before being planted and forced outdoors at 21–25°C day temperatures and 10–14°C night temperatures. Low-temperature treatment at 3–5°C was necessary to obtain satisfactory shoot growth and flowering after planting. The rate of plant emergence, shoot growth and the percentage of flowering increased with increasing duration of cold treatment. The period from corm planting to flowering was inversely related to the duration of the cold treatment, optimum duration resulting in early flowering, more uniform flowering and an increase in length of the inflorescences. The non-cold-treated corms, or those which received inadequate low-temperature treatment, resulted in poor and slow plant emergence, many non-flowering shoots and very slow stem elongation for both flowering and non-flowering shoots.

Differential Orchard Fireblight Susceptibility of Young Apple Stions1

Abstract Marked variations in the number of fireblight infections were observed on 3-year old ‘Double Red Jonathan’ stions grafted on 8 size-controlling clonal rootstocks. The average number of fireblight infections per tree ranged from 33 with the MM 109 rootstock to 0 with the Alnarp 2 rootstock. The number of fireblight infections was correlated with the number of flower clusters on the stions (r= .70**) but was not correlated with stion vigor as expressed by trunk circumference (r=-.18). The number of fireblight infections on non-flowering shoots also was correlated with the number of flower clusters on the stion (r= .60**) but was not correlated with trunk circumference (r= -.20). The susceptibility of non-flowering shoots to fireblight was influenced by the number of flower clusters on the stion, but flowers were not an essential avenue of bacterial infection, even when present. Within the Merton-Mailing rootstock series, the number of flower clusters was not correlated with the size of the stion.

Differential Orchard Fireblight Susceptibility of Young Apple Stions1

Abstract Marked variations in the number of fireblight infections were observed on 3-year old ‘Double Red Jonathan’ stions grafted on 8 size-controlling clonal rootstocks. The average number of fireblight infections per tree ranged from 33 with the MM 109 rootstock to 0 with the Alnarp 2 rootstock. The number of fireblight infections was correlated with the number of flower clusters on the stions (r= .70**) but was not correlated with stion vigor as expressed by trunk circumference (r=-.18). The number of fireblight infections on non-flowering shoots also was correlated with the number of flower clusters on the stion (r= .60**) but was not correlated with trunk circumference (r= -.20). The susceptibility of non-flowering shoots to fireblight was influenced by the number of flower clusters on the stion, but flowers were not an essential avenue of bacterial infection, even when present. Within the Merton-Mailing rootstock series, the number of flower clusters was not correlated with the size of the stion.