Vegetative and Reproductive Growth and Yield of Plukenetia volubilis Plants in Responses to Foliar Application of Plant Growth Regulators

Abstract

<jats:p><jats:italic>Plukenetia volubilis</jats:italic> Linneo, a tropical recurrent woody oilseed plant native to South America, was successfully introduced in China. A field experiment was conducted to determine the effect of the dry-season foliar sprays once every 2 weeks with 50 μ<jats:sc>m</jats:sc> water or five different plant growth regulators (PGRs) viz., gibberellic acid (GA<jats:sub>3</jats:sub>), kinetin (KIN), indole-3-acetic acid (IAA), abscisic acid (ABA), and salicylic acid (SA) on the growth and yield of <jats:italic>P. volubilis</jats:italic> plants in Xishuangbanna, southwest China. Results showed that PGRs affected the leaf stomatal conductance (<jats:italic>g</jats:italic><jats:sub>S</jats:sub>) and water-use efficiency (WUE<jats:sub>i</jats:sub>), rather than the net photosynthetic rate (P<jats:sub>N</jats:sub>). The phenological development of <jats:italic>P. volubilis</jats:italic> plants, including the time of flowering and maturity, and the dynamic pattern of fruit ripening, was not altered by PGR treatments. ABA and SA resulted in highest fruit set, seed oil content, and total fruit or seed oil yield, whereas GA<jats:sub>3</jats:sub>, IAA, and KIN were effective in increasing seed size. The nonstructural carbohydrates (NSC) are related to subsequent abscission or retention of the developing fruit, which was indicated by the positive relationship between carbohydrate concentration and fruit set across PGR treatments. The positive influences of PGRs on the total fruit yield (increased 4.3% to 15.2%) and total seed oil yield (increased 4.9% to 24.9%) per unit area throughout a growing season were found when compared with the control, depending to a great extent on the balance between vegetative and reproductive growth during the reproductive stage. This study suggests that PGRs, especially for ABA and SA, can become a valuable tool for promoting the seed oil yield of <jats:italic>P. volubilis</jats:italic> plants while maintaining high seed quality in the field.</jats:p>

Yield and resource use efficiency of Plukenetia volubilis plants at two distinct growth stages as affected by irrigation and fertilization

“…Irrigation and fertilization did not affect the pattern of fruit ripening of P. volubilis plants, which is in accordance with our previous studies 19 , 25 , 26 , 38 . This may be because a woody plant’s phenology with no requirement for vernalisation within a growing season is largely determined by its responses to temperature and photoperiod 39 , 40 .…”

“…growth) and maintenance processes (e.g. respiration), associations between changes in carbohydrate concentration and plant growth rate could help to explain whether source–sink dynamics influence the pattern of physiological acclimation of P. volubilis plants to a fluctuating environment 37 , 38 .…”

“…1 ). Carbohydrate availability can influence yield by adjusting the fruit number to the metabolite supply of the plant through the premature abscission of flowers and developing fruits 35 , 38 . However, it has also been reported that the status of carbohydrates is not a yield determinant of large tree crops, such as cacao 44 and olive tree 45 .…”

Grafting as a strategy to increase flowering of cassava

“…The transition from the vegetative to the reproductive stage depends on both endogenous (hormones) and environmental (temperature and photoperiod) signaling, determined by the differentiation of the apical meristem, where the cells undergo changes in development ( Bernier and Périlleux, 2005 ). This change of the apical meristem can be induced by the exogenous application of growth regulators such as auxins, gibberellins, abscisic acid and ethylene ( Yang et al, 2016 ). In addition, flowering is initiated from the floral signs, also called floral or florigen stimulus.…”

Source–Sink Manipulations Differentially Affected Carbon and Nitrogen Dynamics, Fruit Metabolites and Yield of Sacha Inchi Plants

“…Since P. volubilis plants have extremely small root biomass fraction (ca. 6%) and store only very little NSC in roots [27,34], vegetative aboveground tissues have to assume these functions. NSC contents across plant tissues on diurnal and seasonal scales are generally assumed to be indicative of the C balance, i.e., the difference between C supply (photosynthesis) and demand (export and growth) [5,8,31].…”