Evaluasi Cendawan Endofit Asal Tanaman Karet untuk Mengendalikan Colletotrichum gloeosporioides Patogen Penyakit Gugur Daun Colletotrichum

<p><em>Colletotrichum leaf fall disease caused by </em>Colletotrichum gloeosporioides<em> is an important disease in rubber plants. The </em>C. gloeosporioides<strong><em> </em></strong><em>Infection can reduce production by 7%-45%. Controlling the pathogen using endophytic fungi is very promising because it can suppress inoculum and pathogen colonization, induce plant resistance, and trigger plant growth. The study aimed to evaluate the endophytic fungus isolate from rubber to control </em>C. gloeosporioides<strong><em> </em></strong><em>as a pathogen that caused the rubber leaf fall disease. This research was carried out in the laboratory and greenhouse of the Indonesian Industrial and Beverage Crop Research Institute (IIBCRI), Sukabumi, from March to November 2018. The isolates used were endophytic fungi isolates from rubber plants, which were tested for their inhibition against </em>C. gloeosporioides<em> in vitro on rubber leaves and seedlings, and their mechanism. The variable observed were the inhibition rate, incubation periods, number of spots, disease severity, and plant growth. The results showed that the endophytic fungus could inhibit the growth of </em>C. gloeosporioides<em> about 64.17% - 86.67%. The high inhibitory activity (&gt;80%) in isolates CEPR.19, CEPR.6, CEBPM.21, DTJE.1, and DMJE27 were 86.67%; 83.33%; 83.33%; 82.92%, and 82.50%, respectively. The observations on seedlings obtained three potential fungal isolates to control </em>C. gloeosporioides<em> on rubber leaves, namely CEBPM.21, CEPR19, and DTJE.1 with suppression of disease severity about 68.57%; 67.88%, and 60.20% with their mechanisms of action inducing resistance, antibiosis, competition, and hyperparasites.</em><em></em></p>

Chemical Composition of Oroxylum indicum: A Review

Root bark of sonapatha is an astringent, tonic, anti-diarrhoeal, diuretic, anodyne, and is used to cure dropsy. It is an ingredient of ‘dashamoolarishta’ of Ayurvedic medicine. Stem bark is anti-rheumatic. An infusion of bark powder is diaphoretic. Tender fruits have spas- molytic, carminative, and stomachic properties, while seeds are purgative.it is a medium-sized, soft-wooded tree attaining a height of 10–16 m. Stem bark is dull brown in colour; leaves are broad, 60–120 cm in length and pinnately compound. Leaflets are ovate, wavy, and acuminate. Leaf fall occurs during winter season (January) each year. The tree is recognized by ternately bipinnate leaves. The root bark contains chrysin, baicalein, dehydrobaicalein, and orozylin. Stem bark possesses flavonoids such as oroxylin, baicalein, scutelarin and 7-rutinoside, chrysin, and p-coumaric acid. Heartwood yields β-sitosterol and isoflavone-prunetin. Root bark of sonapatha is an astringent, tonic, anti-diarrhoeal, diuretic, anodyne, and is used to cure dropsy. It is an ingredient of ‘dashamoolarishta’ of Ayurvedic medicine. Stem bark is anti-rheumatic. An infusion of bark powder is diaphoretic. Tender fruits have spas- molytic, carminative, and stomachic properties, while seeds are purgative. It is a medium-sized, soft-wooded tree attaining a height of 10–16 m. Stem bark is dull brown in colour; leaves are broad, 60–120 cm in length and pinnately compound. Leaflets are ovate, wavy, and acuminate. Leaf fall occurs during winter season (January) each year. The tree is recognized by ternately bipinnate leaves. The root bark contains chrysin, baicalein, dehydrobaicalein, and orozylin. Stem bark possesses flavonoids such as oroxylin, baicalein, scutelarin.

The palm leaves falling periods and characteristics of royal palm (Roystonea regia (Kunth) F.Cook) at IPB Dramaga Campus, Bogor, Indonesia

Royal palm is widely planted as an ornamental plant and becomes part of parks and open landscapes in urban areas, especially on the roadside and in an urban forest. The leaves have a large size that can potentially cause harm to people or property under or around the tree. Information regarding the falling period and the weight of palm leaves was necessary in terms of risk mitigation of tree management. The study was conducted on ten royal palm trees by observing the incidence of leaf fall every three days during the period of September 2019 to March 2020. The palm leaves comprise the leaf sheath and the petiole. The results showed that the number of royal palm leaves was about 12 leaves per tree. Royal palm at IPB Dramaga campus has a tree height of about 12 m and a diameter of 40 cm. The period of fall of palm leaves is 30 to 40 days; although it may not fall every period, it can even fall once in 6 months. The average weight of the fallen leaves is about 8.2 kg, with a moisture content of 85.2%. Information on the period and weight of royal palm leaf fall are very important as information on risk mitigation activities in plant management in the urban landscape.

First report of Golovinomyces sp. causing powdery mildew infection on Dyschoriste nagchana in Western Ghats of India

Dyschoriste nagchana Nees (Acanthaceae) is a perennial plant grows naturally in wet grassland, but is now often also found in secondary bushland and grassland, including lawns. In January2019, severe powdery mildew symptoms were observed on the leaves and stem of D. nagchana (Fig.1, a). The infection was found to be very severe at that time on plant and because of severe infestation premature leaf fall was also observed. The occurrence of powdery mildew in its anamorphic form on D. nagchana. was first observed in the ranges of hills in Western Ghats pertaining to district Satara viz Yavateshwar (17°41’02.91”N 73°56’58.15”E and Elevation 3419ft) and Varoshi (17°52’04.42” N 73°45’03.12” E and Elevation 2834ft). later on, disease incidence was noticed from different areas of said district.

Qualitative and Quantitative Indicators of Foliar Mass of Woody Plants in Urban Greenspaces According to the Level of Air Pollution

The purpose of this study is to conduct a comparative analysis of the leaf fall timing and parameters of fluctuating leaf asymmetry among two commonly used plant species for street landscaping in Detroit city, namely, American elm and American ash. The study was completed between summer and fall for the year 2019 in and around Detroit, US. Phenological leaf fall timing of elm and ash was studied, and the fluctuating asymmetry index of their leaves was estimated within the city limits (80 trees of ash and 40 of elm) and outside the city (control site, 20 trees of each species). Leaf fall in city ash trees was recorded from November 1st to 4th and 5-8 days prior to the leaf fall in elms (p ≤ 0.01). Elm trees in the control group shed their leaves 10 days later compared to the city trees, i.e., on average, on November 25th (p ≤ 0.01). Ash trees in the control group shed their leaves earlier than the elm control group, on November 11th (p ≤ 0.001). In the city streets, the average fluctuating asymmetry ranged from 0.065 to 0.086 (point 1), from 0.049 to 0.078 (point 2) and from 0.063 to 0.082 (control site, near the highway).

Drought effects on leaf fall, leaf flushing and stem growth in the Amazon forest: reconciling remote sensing data and field observations

Large amounts of carbon flow through tropical ecosystems every year, from which a part is sequestered in biomass through tree growth. However, the effects of ongoing warming and drying on tree growth and carbon sequestration in tropical forest is still highly uncertain. Field observations are sparse and limited to a few sites, while remote sensing analysis shows diverging growth responses to past droughts that cannot be interpreted with confidence. To reconcile data from field observations and remote sensing, we collated in situ measurements of stem growth and leaf litterfall from inventory plots across the Amazon region and other neotropical ecosystems. These data were used to train two machine-learning models and to evaluate model performance on reproducing stem growth and litterfall rates. The models utilized multiple climatological variables and other geospatial datasets (terrain, soil and vegetation properties) as explanatory variables. The output consisted of monthly estimates of leaf litterfall (R2= 0.71, NRMSE = 9.4 %) and stem growth (R2= 0.54, NRMSE = 10.6 %) across the neotropics from 1982 to 2019 at a high spatial resolution (0.1∘). Modelled time series allow us to assess the impacts of the 2005 and 2015 droughts in the Amazon basin on regional scales. The more severe 2015 drought was estimated to have caused widespread declines in stem growth (−1.8σ), coinciding with enhanced leaf fall (+1.4σ), which were only locally apparent in 2005. Regions in the Amazon basin that flushed leaves at the onset of both droughts (+0.9σ∼+2.0σ) showed positive anomalies in remotely sensed enhanced vegetation index, while sun-induced fluorescence and vegetation optical depth were reduced. The previously observed counterintuitive response of canopy green-up during drought in the Amazon basin detected by many remote sensing analyses can therefore be a result of enhanced leaf flushing at the onset of a drought. The long-term estimates of leaf litterfall and stem growth point to a decline in stem growth and a simultaneous increase in leaf litterfall in the Amazon basin since 1982. These trends are associated with increased warming and drying of the Amazonian climate and could point to a further decline in the Amazon carbon sink strength.

Effects of the Simulated Enhancement of Precipitation on the Phenology of Nitraria tangutorum under Extremely Dry and Wet Years

Plant phenology is the most sensitive biological indicator that responds to climate change. Many climate models predict that extreme precipitation events will occur frequently in the arid areas of northwest China in the future, with an increase in the quantity and unpredictability of rain. Future changes in precipitation will inevitably have a profound impact on plant phenology in arid areas. A recent study has shown that after the simulated enhancement of precipitation, the end time of the leaf unfolding period of Nitraria tangutorum advanced, and the end time of leaf senescence was delayed. Under extreme climatic conditions, such as extremely dry or wet years, it is unclear whether the influence of the simulated enhancement of precipitation on the phenology of N. tangutorum remains stable. To solve this problem, this study systematically analyzed the effects of the simulated enhancement of precipitation on the start, end and duration of four phenological events of N. tangutorum, including leaf budding, leaf unfolding, leaf senescence and leaf fall under extremely dry and wet conditions. The aim of this study was to clarify the similarities and differences of the effects of the simulated enhancement of precipitation on the start, end and duration of each phenological period of N. tangutorum in an extremely dry and an extremely wet year to reveal the regulatory effect of extremely dry and excessive amounts of precipitation on the phenology of N. tangutorum. (1) After the simulated enhancement of precipitation, the start and end times of the spring phenology (leaf budding and leaf unfolding) of N. tangutorum advanced during an extremely dry and an extremely wet year, but the duration of phenology was shortened during an extremely wet year and prolonged during an extremely drought-stricken year. The amplitude of variation increased with the increase in simulated precipitation. (2) After the simulated enhancement of precipitation, the start and end times of the phenology (leaf senescence and leaf fall) of N. tangutorum during the autumn advanced in an extremely wet year but was delayed during an extremely dry year, and the duration of phenology was prolonged in both extremely dry and wet years. The amplitude of variation increased with the increase in simulated precipitation. (3) The regulation mechanism of extremely dry or wet years on the spring phenology of N. tangutorum lay in the different degree of influence on the start and end times of leaf budding and leaf unfolding. However, the regulation mechanism of extremely dry or wet years on the autumn phenology of N. tangutorum lay in different reasons. Water stress caused by excessive water forced N. tangutorum to start its leaf senescence early during an extremely wet year. In contrast, the alleviation of drought stress after watering during the senescence of N. tangutorum caused a delay in the autumn phenology during an extremely dry year.

Ethylene-Mediated Modulation of Bud Phenology, Cold Hardiness, and Hormone Biosynthesis in Peach (Prunus persica)

Spring frosts exacerbated by global climate change have become a constant threat to temperate fruit production. Delaying the bloom date by plant growth regulators (PGRs) has been proposed as a practical frost avoidance strategy. Ethephon is an ethylene-releasing PGR found to delay bloom in several fruit species, yet its use is often coupled with harmful effects, limiting its applicability in commercial tree fruit production. Little information is available regarding the mechanisms by which ethephon influences blooming and bud dormancy. This study investigated the effects of fall-applied ethephon on bud phenology, cold hardiness, and hormonal balance throughout the bud dormancy cycle in peach. Our findings concluded that ethephon could alter several significant aspects of peach bud physiology, including accelerated leaf fall, extended chilling accumulation period, increased heat requirements, improved cold hardiness, and delayed bloom date. Ethephon effects on these traits were primarily dependent on its concentration and application timing, with a high concentration (500 ppm) and an early application timing (10% leaf fall) being the most effective. Endogenous ethylene levels were induced significantly in the buds when ethephon was applied at 10% versus 90% leaf fall, indicating that leaves are essential for ethephon uptake. The hormonal analysis of buds at regular intervals of chilling hours (CH) and growing degree hours (GDH) also indicated that ethephon might exert its effects through an abscisic acid (ABA)-independent way in dormant buds. Instead, our data signifies the role of jasmonic acid (JA) in mediating budburst and bloom in peach, which also appears to be influenced by ethephon treatment. Overall, this research presents a new perspective in interpreting horticultural traits in the light of biochemical and molecular data and sheds light on the potential role of JA in bud dormancy, which deserves further attention in future studies that aim at mitigating spring frosts.

DIAGNOSIS PENYAKIT GUGUR DAUN KARET (Hevea brasiliensis Muell. Arg.)

One of the causal of the low rubber production is the presence of plant diseases. Important diseases in rubber plants generally cause symptoms of leaf fall, due to Colletotrichum spp., Corynespora sp., and Oidium sp. Currently, there is an incidence of new rubber leaf fall disease with symptoms that are different from the diseases previously found in rubber plantations. This disease is widespread in Sumatra, Kalimantan, and Southeast Asia. There are many suspicions about the pathogens that cause the disease, but there is no precise diagnosis. Therefore, an accurate diagnosis is needed as a basis for determining an effective and efficient disease control strategy. This research was carried out to determine the causal agents of leaf fall disease with symptoms of round leaf spots that can cause leaf fall. Diagnosis was carried out by isolating the pathogen from several rubber clones, inoculating the pathogen to healthy rubber plants, identifying morphologically and molecularly, and re-isolating from inoculated plants. The results of Koch's postulates and morphological and molecular identification determined that the causal agents of leaf fall disease at rubber plants with round spots was the fungus Pestalotiopsis microspora.